diff --git a/apps/openmw/mwworld/scene.cpp b/apps/openmw/mwworld/scene.cpp
index bfd21d5e27..ca19383d15 100644
--- a/apps/openmw/mwworld/scene.cpp
+++ b/apps/openmw/mwworld/scene.cpp
@@ -282,6 +282,9 @@ namespace MWWorld
             mPhysics->remove(ptr);
         }
 
+        const auto cellX = (*iter)->getCell()->getGridX();
+        const auto cellY = (*iter)->getCell()->getGridY();
+
         if ((*iter)->getCell()->isExterior())
         {
             const ESM::Land* land =
@@ -291,14 +294,15 @@ namespace MWWorld
                 );
             if (land && land->mDataTypes&ESM::Land::DATA_VHGT)
             {
-                const auto cellX = (*iter)->getCell()->getGridX();
-                const auto cellY = (*iter)->getCell()->getGridY();
                 if (const auto heightField = mPhysics->getHeightField(cellX, cellY))
                     navigator->removeObject(reinterpret_cast<std::size_t>(heightField));
                 mPhysics->removeHeightField(cellX, cellY);
             }
         }
 
+        if ((*iter)->getCell()->hasWater())
+            navigator->removeWater(osg::Vec2i(cellX, cellY));
+
         navigator->update(player.getRefData().getPosition().asVec3());
 
         MWBase::Environment::get().getMechanicsManager()->drop (*iter);
@@ -326,11 +330,12 @@ namespace MWWorld
 
             const auto navigator = MWBase::Environment::get().getWorld()->getNavigator();
 
+            const int cellX = cell->getCell()->getGridX();
+            const int cellY = cell->getCell()->getGridY();
+
             // Load terrain physics first...
             if (cell->getCell()->isExterior())
             {
-                int cellX = cell->getCell()->getGridX();
-                int cellY = cell->getCell()->getGridY();
                 osg::ref_ptr<const ESMTerrain::LandObject> land = mRendering.getLandManager()->getLand(cellX, cellY);
                 const ESM::Land::LandData* data = land ? land->getData(ESM::Land::DATA_VHGT) : 0;
                 if (data)
@@ -368,6 +373,18 @@ namespace MWWorld
             {
                 mPhysics->enableWater(waterLevel);
                 mRendering.setWaterHeight(waterLevel);
+
+                if (cell->getCell()->isExterior())
+                {
+                    if (const auto heightField = mPhysics->getHeightField(cellX, cellY))
+                        navigator->addWater(osg::Vec2i(cellX, cellY), ESM::Land::REAL_SIZE,
+                            cell->getWaterLevel(), heightField->getCollisionObject()->getWorldTransform());
+                }
+                else
+                {
+                    navigator->addWater(osg::Vec2i(cellX, cellY), std::numeric_limits<int>::max(),
+                        cell->getWaterLevel(), btTransform::getIdentity());
+                }
             }
             else
                 mPhysics->disableWater();
diff --git a/apps/openmw/mwworld/scene.hpp b/apps/openmw/mwworld/scene.hpp
index e1144d97a2..c8578fc354 100644
--- a/apps/openmw/mwworld/scene.hpp
+++ b/apps/openmw/mwworld/scene.hpp
@@ -6,6 +6,7 @@
 
 #include <set>
 #include <memory>
+#include <unordered_map>
 
 namespace osg
 {
@@ -27,6 +28,11 @@ namespace Loading
     class Listener;
 }
 
+namespace DetourNavigator
+{
+    class Water;
+}
+
 namespace MWRender
 {
     class SkyManager;
diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index a7bda8c0be..bb8bd9615a 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -168,42 +168,6 @@ namespace MWWorld
       mLevitationEnabled(true), mGoToJail(false), mDaysInPrison(0),
       mPlayerTraveling(false), mPlayerInJail(false), mSpellPreloadTimer(0.f)
     {
-        mPhysics.reset(new MWPhysics::PhysicsSystem(resourceSystem, rootNode));
-
-        DetourNavigator::Settings navigatorSettings;
-        navigatorSettings.mBorderSize = Settings::Manager::getInt("border size", "Navigator");
-        navigatorSettings.mCellHeight = Settings::Manager::getFloat("cell height", "Navigator");
-        navigatorSettings.mCellSize = Settings::Manager::getFloat("cell size", "Navigator");
-        navigatorSettings.mDetailSampleDist = Settings::Manager::getFloat("detail sample dist", "Navigator");
-        navigatorSettings.mDetailSampleMaxError = Settings::Manager::getFloat("detail sample max error", "Navigator");
-        navigatorSettings.mMaxClimb = MWPhysics::sStepSizeUp;
-        navigatorSettings.mMaxSimplificationError = Settings::Manager::getFloat("max simplification error", "Navigator");
-        navigatorSettings.mMaxSlope = MWPhysics::sMaxSlope;
-        navigatorSettings.mRecastScaleFactor = Settings::Manager::getFloat("recast scale factor", "Navigator");
-        navigatorSettings.mMaxEdgeLen = Settings::Manager::getInt("max edge len", "Navigator");
-        navigatorSettings.mMaxNavMeshQueryNodes = Settings::Manager::getInt("max nav mesh query nodes", "Navigator");
-        navigatorSettings.mMaxVertsPerPoly = Settings::Manager::getInt("max verts per poly", "Navigator");
-        navigatorSettings.mRegionMergeSize = Settings::Manager::getInt("region merge size", "Navigator");
-        navigatorSettings.mRegionMinSize = Settings::Manager::getInt("region min size", "Navigator");
-        navigatorSettings.mTileSize = Settings::Manager::getInt("tile size", "Navigator");
-        navigatorSettings.mMaxPolygonPathSize = static_cast<std::size_t>(Settings::Manager::getInt("max polygon path size", "Navigator"));
-        navigatorSettings.mMaxSmoothPathSize = static_cast<std::size_t>(Settings::Manager::getInt("max smooth path size", "Navigator"));
-        navigatorSettings.mTrianglesPerChunk = static_cast<std::size_t>(Settings::Manager::getInt("triangles per chunk", "Navigator"));
-        navigatorSettings.mEnableWriteRecastMeshToFile = Settings::Manager::getBool("enable write recast mesh to file", "Navigator");
-        navigatorSettings.mEnableWriteNavMeshToFile = Settings::Manager::getBool("enable write nav mesh to file", "Navigator");
-        navigatorSettings.mRecastMeshPathPrefix = Settings::Manager::getString("recast mesh path prefix", "Navigator");
-        navigatorSettings.mNavMeshPathPrefix = Settings::Manager::getString("nav mesh path prefix", "Navigator");
-        navigatorSettings.mEnableRecastMeshFileNameRevision = Settings::Manager::getBool("enable recast mesh file name revision", "Navigator");
-        navigatorSettings.mEnableNavMeshFileNameRevision = Settings::Manager::getBool("enable nav mesh file name revision", "Navigator");
-        if (Settings::Manager::getBool("enable log", "Navigator"))
-            DetourNavigator::Log::instance().setSink(std::unique_ptr<DetourNavigator::FileSink>(
-                new DetourNavigator::FileSink(Settings::Manager::getString("log path", "Navigator"))));
-        mNavigator.reset(new DetourNavigator::Navigator(navigatorSettings));
-
-        mRendering.reset(new MWRender::RenderingManager(viewer, rootNode, resourceSystem, workQueue, &mFallback, resourcePath, *mNavigator));
-        mProjectileManager.reset(new ProjectileManager(mRendering->getLightRoot(), resourceSystem, mRendering.get(), mPhysics.get()));
-        mRendering->preloadCommonAssets();
-
         mEsm.resize(contentFiles.size());
         Loading::Listener* listener = MWBase::Environment::get().getWindowManager()->getLoadingScreen();
         listener->loadingOn();
@@ -232,6 +196,43 @@ namespace MWWorld
 
         mSwimHeightScale = mStore.get<ESM::GameSetting>().find("fSwimHeightScale")->mValue.getFloat();
 
+        mPhysics.reset(new MWPhysics::PhysicsSystem(resourceSystem, rootNode));
+
+        DetourNavigator::Settings navigatorSettings;
+        navigatorSettings.mBorderSize = Settings::Manager::getInt("border size", "Navigator");
+        navigatorSettings.mCellHeight = Settings::Manager::getFloat("cell height", "Navigator");
+        navigatorSettings.mCellSize = Settings::Manager::getFloat("cell size", "Navigator");
+        navigatorSettings.mDetailSampleDist = Settings::Manager::getFloat("detail sample dist", "Navigator");
+        navigatorSettings.mDetailSampleMaxError = Settings::Manager::getFloat("detail sample max error", "Navigator");
+        navigatorSettings.mMaxClimb = MWPhysics::sStepSizeUp;
+        navigatorSettings.mMaxSimplificationError = Settings::Manager::getFloat("max simplification error", "Navigator");
+        navigatorSettings.mMaxSlope = MWPhysics::sMaxSlope;
+        navigatorSettings.mRecastScaleFactor = Settings::Manager::getFloat("recast scale factor", "Navigator");
+        navigatorSettings.mSwimHeightScale = mSwimHeightScale;
+        navigatorSettings.mMaxEdgeLen = Settings::Manager::getInt("max edge len", "Navigator");
+        navigatorSettings.mMaxNavMeshQueryNodes = Settings::Manager::getInt("max nav mesh query nodes", "Navigator");
+        navigatorSettings.mMaxVertsPerPoly = Settings::Manager::getInt("max verts per poly", "Navigator");
+        navigatorSettings.mRegionMergeSize = Settings::Manager::getInt("region merge size", "Navigator");
+        navigatorSettings.mRegionMinSize = Settings::Manager::getInt("region min size", "Navigator");
+        navigatorSettings.mTileSize = Settings::Manager::getInt("tile size", "Navigator");
+        navigatorSettings.mMaxPolygonPathSize = static_cast<std::size_t>(Settings::Manager::getInt("max polygon path size", "Navigator"));
+        navigatorSettings.mMaxSmoothPathSize = static_cast<std::size_t>(Settings::Manager::getInt("max smooth path size", "Navigator"));
+        navigatorSettings.mTrianglesPerChunk = static_cast<std::size_t>(Settings::Manager::getInt("triangles per chunk", "Navigator"));
+        navigatorSettings.mEnableWriteRecastMeshToFile = Settings::Manager::getBool("enable write recast mesh to file", "Navigator");
+        navigatorSettings.mEnableWriteNavMeshToFile = Settings::Manager::getBool("enable write nav mesh to file", "Navigator");
+        navigatorSettings.mRecastMeshPathPrefix = Settings::Manager::getString("recast mesh path prefix", "Navigator");
+        navigatorSettings.mNavMeshPathPrefix = Settings::Manager::getString("nav mesh path prefix", "Navigator");
+        navigatorSettings.mEnableRecastMeshFileNameRevision = Settings::Manager::getBool("enable recast mesh file name revision", "Navigator");
+        navigatorSettings.mEnableNavMeshFileNameRevision = Settings::Manager::getBool("enable nav mesh file name revision", "Navigator");
+        if (Settings::Manager::getBool("enable log", "Navigator"))
+            DetourNavigator::Log::instance().setSink(std::unique_ptr<DetourNavigator::FileSink>(
+                new DetourNavigator::FileSink(Settings::Manager::getString("log path", "Navigator"))));
+        mNavigator.reset(new DetourNavigator::Navigator(navigatorSettings));
+
+        mRendering.reset(new MWRender::RenderingManager(viewer, rootNode, resourceSystem, workQueue, &mFallback, resourcePath, *mNavigator));
+        mProjectileManager.reset(new ProjectileManager(mRendering->getLightRoot(), resourceSystem, mRendering.get(), mPhysics.get()));
+        mRendering->preloadCommonAssets();
+
         mWeatherManager.reset(new MWWorld::WeatherManager(*mRendering, mFallback, mStore));
 
         mWorldScene.reset(new Scene(*mRendering.get(), mPhysics.get()));
diff --git a/apps/openmw_test_suite/detournavigator/navigator.cpp b/apps/openmw_test_suite/detournavigator/navigator.cpp
index aa7906008a..84aa344744 100644
--- a/apps/openmw_test_suite/detournavigator/navigator.cpp
+++ b/apps/openmw_test_suite/detournavigator/navigator.cpp
@@ -48,6 +48,7 @@ namespace
             mSettings.mMaxSimplificationError = 1.3f;
             mSettings.mMaxSlope = 49;
             mSettings.mRecastScaleFactor = 0.017647058823529415f;
+            mSettings.mSwimHeightScale = 0.89999997615814208984375f;
             mSettings.mMaxEdgeLen = 12;
             mSettings.mMaxNavMeshQueryNodes = 2048;
             mSettings.mMaxVertsPerPoly = 6;
@@ -415,4 +416,142 @@ namespace
             osg::Vec3f(215, -215, 1.93937528133392333984375),
         })) << mPath;
     }
+
+    TEST_F(DetourNavigatorNavigatorTest, path_should_be_over_water_ground_lower_than_water)
+    {
+        std::array<btScalar, 5 * 5> heightfieldData {{
+            -50,  -50,  -50,  -50,    0,
+            -50, -100, -150, -100,  -50,
+            -50, -150, -200, -150, -100,
+            -50, -100, -150, -100, -100,
+              0,  -50, -100, -100, -100,
+        }};
+        btHeightfieldTerrainShape shape(5, 5, heightfieldData.data(), 1, 0, 0, 2, PHY_FLOAT, false);
+        shape.setLocalScaling(btVector3(128, 128, 1));
+
+        mNavigator->addAgent(mAgentHalfExtents);
+        mNavigator->addWater(osg::Vec2i(0, 0), 128 * 4, 300, btTransform::getIdentity());
+        mNavigator->addObject(1, shape, btTransform::getIdentity());
+        mNavigator->update(mPlayerPosition);
+        mNavigator->wait();
+
+        mStart.x() = 0;
+        mStart.z() = 300;
+        mEnd.x() = 0;
+        mEnd.z() = 300;
+
+        mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, mOut);
+
+        EXPECT_EQ(mPath, std::deque<osg::Vec3f>({
+            osg::Vec3f(0, 215, 185.33331298828125),
+            osg::Vec3f(0, 186.6666717529296875, 185.33331298828125),
+            osg::Vec3f(0, 158.333343505859375, 185.33331298828125),
+            osg::Vec3f(0, 130.0000152587890625, 185.33331298828125),
+            osg::Vec3f(0, 101.66667938232421875, 185.33331298828125),
+            osg::Vec3f(0, 73.333343505859375, 185.33331298828125),
+            osg::Vec3f(0, 45.0000152587890625, 185.33331298828125),
+            osg::Vec3f(0, 16.6666812896728515625, 185.33331298828125),
+            osg::Vec3f(0, -11.66664981842041015625, 185.33331298828125),
+            osg::Vec3f(0, -39.999980926513671875, 185.33331298828125),
+            osg::Vec3f(0, -68.33331298828125, 185.33331298828125),
+            osg::Vec3f(0, -96.66664886474609375, 185.33331298828125),
+            osg::Vec3f(0, -124.99997711181640625, 185.33331298828125),
+            osg::Vec3f(0, -153.33331298828125, 185.33331298828125),
+            osg::Vec3f(0, -181.6666412353515625, 185.33331298828125),
+            osg::Vec3f(0, -209.999969482421875, 185.33331298828125),
+            osg::Vec3f(0, -215, 185.33331298828125),
+        })) << mPath;
+    }
+
+    TEST_F(DetourNavigatorNavigatorTest, path_should_be_over_water_when_ground_cross_water)
+    {
+        std::array<btScalar, 7 * 7> heightfieldData {{
+            0,    0,    0,    0,    0,    0, 0,
+            0, -100, -100, -100, -100, -100, 0,
+            0, -100, -150, -150, -150, -100, 0,
+            0, -100, -150, -200, -150, -100, 0,
+            0, -100, -150, -150, -150, -100, 0,
+            0, -100, -100, -100, -100, -100, 0,
+            0,    0,    0,    0,    0,    0, 0,
+        }};
+        btHeightfieldTerrainShape shape(7, 7, heightfieldData.data(), 1, 0, 0, 2, PHY_FLOAT, false);
+        shape.setLocalScaling(btVector3(128, 128, 1));
+
+        mNavigator->addAgent(mAgentHalfExtents);
+        mNavigator->addWater(osg::Vec2i(0, 0), 128 * 4, -25, btTransform::getIdentity());
+        mNavigator->addObject(1, shape, btTransform::getIdentity());
+        mNavigator->update(mPlayerPosition);
+        mNavigator->wait();
+
+        mStart.x() = 0;
+        mEnd.x() = 0;
+
+        mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, mOut);
+
+        EXPECT_EQ(mPath, std::deque<osg::Vec3f>({
+            osg::Vec3f(0, 215, -94.75363922119140625),
+            osg::Vec3f(0, 186.6666717529296875, -106.0000152587890625),
+            osg::Vec3f(0, 158.333343505859375, -115.85507965087890625),
+            osg::Vec3f(0, 130.0000152587890625, -125.71016693115234375),
+            osg::Vec3f(0, 101.66667938232421875, -135.5652313232421875),
+            osg::Vec3f(0, 73.333343505859375, -143.3333587646484375),
+            osg::Vec3f(0, 45.0000152587890625, -143.3333587646484375),
+            osg::Vec3f(0, 16.6666812896728515625, -143.3333587646484375),
+            osg::Vec3f(0, -11.66664981842041015625, -143.3333587646484375),
+            osg::Vec3f(0, -39.999980926513671875, -143.3333587646484375),
+            osg::Vec3f(0, -68.33331298828125, -143.3333587646484375),
+            osg::Vec3f(0, -96.66664886474609375, -137.3043670654296875),
+            osg::Vec3f(0, -124.99997711181640625, -127.44930267333984375),
+            osg::Vec3f(0, -153.33331298828125, -117.5942230224609375),
+            osg::Vec3f(0, -181.6666412353515625, -107.7391510009765625),
+            osg::Vec3f(0, -209.999969482421875, -97.79712677001953125),
+            osg::Vec3f(0, -215, -94.753631591796875),
+        })) << mPath;
+    }
+
+    TEST_F(DetourNavigatorNavigatorTest, path_should_be_over_water_when_ground_cross_water_with_max_int_cells_size)
+    {
+        std::array<btScalar, 7 * 7> heightfieldData {{
+            0,    0,    0,    0,    0,    0, 0,
+            0, -100, -100, -100, -100, -100, 0,
+            0, -100, -150, -150, -150, -100, 0,
+            0, -100, -150, -200, -150, -100, 0,
+            0, -100, -150, -150, -150, -100, 0,
+            0, -100, -100, -100, -100, -100, 0,
+            0,    0,    0,    0,    0,    0, 0,
+        }};
+        btHeightfieldTerrainShape shape(7, 7, heightfieldData.data(), 1, 0, 0, 2, PHY_FLOAT, false);
+        shape.setLocalScaling(btVector3(128, 128, 1));
+
+        mNavigator->addAgent(mAgentHalfExtents);
+        mNavigator->addObject(1, shape, btTransform::getIdentity());
+        mNavigator->addWater(osg::Vec2i(0, 0), std::numeric_limits<int>::max(), -25, btTransform::getIdentity());
+        mNavigator->update(mPlayerPosition);
+        mNavigator->wait();
+
+        mStart.x() = 0;
+        mEnd.x() = 0;
+
+        mNavigator->findPath(mAgentHalfExtents, mStart, mEnd, mOut);
+
+        EXPECT_EQ(mPath, std::deque<osg::Vec3f>({
+            osg::Vec3f(0, 215, -94.75363922119140625),
+            osg::Vec3f(0, 186.6666717529296875, -106.0000152587890625),
+            osg::Vec3f(0, 158.333343505859375, -115.85507965087890625),
+            osg::Vec3f(0, 130.0000152587890625, -125.71016693115234375),
+            osg::Vec3f(0, 101.66667938232421875, -135.5652313232421875),
+            osg::Vec3f(0, 73.333343505859375, -143.3333587646484375),
+            osg::Vec3f(0, 45.0000152587890625, -143.3333587646484375),
+            osg::Vec3f(0, 16.6666812896728515625, -143.3333587646484375),
+            osg::Vec3f(0, -11.66664981842041015625, -143.3333587646484375),
+            osg::Vec3f(0, -39.999980926513671875, -143.3333587646484375),
+            osg::Vec3f(0, -68.33331298828125, -143.3333587646484375),
+            osg::Vec3f(0, -96.66664886474609375, -137.3043670654296875),
+            osg::Vec3f(0, -124.99997711181640625, -127.44930267333984375),
+            osg::Vec3f(0, -153.33331298828125, -117.5942230224609375),
+            osg::Vec3f(0, -181.6666412353515625, -107.7391510009765625),
+            osg::Vec3f(0, -209.999969482421875, -97.79712677001953125),
+            osg::Vec3f(0, -215, -94.753631591796875),
+        })) << mPath;
+    }
 }
diff --git a/apps/openmw_test_suite/detournavigator/recastmeshbuilder.cpp b/apps/openmw_test_suite/detournavigator/recastmeshbuilder.cpp
index c27f608a9e..ffef6114c7 100644
--- a/apps/openmw_test_suite/detournavigator/recastmeshbuilder.cpp
+++ b/apps/openmw_test_suite/detournavigator/recastmeshbuilder.cpp
@@ -13,6 +13,14 @@
 
 #include <gtest/gtest.h>
 
+namespace DetourNavigator
+{
+    static inline bool operator ==(const RecastMesh::Water& lhs, const RecastMesh::Water& rhs)
+    {
+        return lhs.mCellSize == rhs.mCellSize && lhs.mTransform == rhs.mTransform;
+    }
+}
+
 namespace
 {
     using namespace testing;
@@ -391,4 +399,14 @@ namespace
         EXPECT_EQ(recastMesh->getIndices(), std::vector<int>({0, 1, 2, 3, 4, 5}));
         EXPECT_EQ(recastMesh->getAreaTypes(), std::vector<AreaType>({AreaType_ground, AreaType_null}));
     }
+
+    TEST_F(DetourNavigatorRecastMeshBuilderTest, add_water_then_get_water_should_return_it)
+    {
+        RecastMeshBuilder builder(mSettings, mBounds);
+        builder.addWater(1000, btTransform(btMatrix3x3::getIdentity(), btVector3(100, 200, 300)));
+        const auto recastMesh = builder.create();
+        EXPECT_EQ(recastMesh->getWater(), std::vector<RecastMesh::Water>({
+            RecastMesh::Water {1000, btTransform(btMatrix3x3::getIdentity(), btVector3(100, 200, 300))}
+        }));
+    }
 }
diff --git a/components/detournavigator/areatype.hpp b/components/detournavigator/areatype.hpp
index 3efaccc44c..0daa524ca1 100644
--- a/components/detournavigator/areatype.hpp
+++ b/components/detournavigator/areatype.hpp
@@ -8,6 +8,7 @@ namespace DetourNavigator
     enum AreaType : unsigned char
     {
         AreaType_null = RC_NULL_AREA,
+        AreaType_water,
         AreaType_ground = RC_WALKABLE_AREA,
     };
 }
diff --git a/components/detournavigator/cachedrecastmeshmanager.cpp b/components/detournavigator/cachedrecastmeshmanager.cpp
index c5ff00a265..8a9fbd4ee8 100644
--- a/components/detournavigator/cachedrecastmeshmanager.cpp
+++ b/components/detournavigator/cachedrecastmeshmanager.cpp
@@ -32,6 +32,23 @@ namespace DetourNavigator
         return object;
     }
 
+    bool CachedRecastMeshManager::addWater(const osg::Vec2i& cellPosition, const int cellSize,
+        const btTransform& transform)
+    {
+        if (!mImpl.addWater(cellPosition, cellSize, transform))
+            return false;
+        mCached.reset();
+        return true;
+    }
+
+    boost::optional<RecastMeshManager::Water> CachedRecastMeshManager::removeWater(const osg::Vec2i& cellPosition)
+    {
+        const auto water = mImpl.removeWater(cellPosition);
+        if (water)
+            mCached.reset();
+        return water;
+    }
+
     std::shared_ptr<RecastMesh> CachedRecastMeshManager::getMesh()
     {
         if (!mCached)
diff --git a/components/detournavigator/cachedrecastmeshmanager.hpp b/components/detournavigator/cachedrecastmeshmanager.hpp
index 15168f9ad6..048d002701 100644
--- a/components/detournavigator/cachedrecastmeshmanager.hpp
+++ b/components/detournavigator/cachedrecastmeshmanager.hpp
@@ -17,6 +17,10 @@ namespace DetourNavigator
 
         bool updateObject(std::size_t id, const btTransform& transform, const AreaType areaType);
 
+        bool addWater(const osg::Vec2i& cellPosition, const int cellSize, const btTransform& transform);
+
+        boost::optional<RecastMeshManager::Water> removeWater(const osg::Vec2i& cellPosition);
+
         boost::optional<RemovedRecastMeshObject> removeObject(std::size_t id);
 
         std::shared_ptr<RecastMesh> getMesh();
diff --git a/components/detournavigator/findsmoothpath.hpp b/components/detournavigator/findsmoothpath.hpp
index 2fbc07c5fd..c145e828c6 100644
--- a/components/detournavigator/findsmoothpath.hpp
+++ b/components/detournavigator/findsmoothpath.hpp
@@ -3,6 +3,7 @@
 
 #include "dtstatus.hpp"
 #include "exceptions.hpp"
+#include "flags.hpp"
 #include "settings.hpp"
 #include "settingsutils.hpp"
 
@@ -10,6 +11,8 @@
 #include <DetourNavMesh.h>
 #include <DetourNavMeshQuery.h>
 
+#include <LinearMath/btVector3.h>
+
 #include <boost/optional.hpp>
 
 #include <osg/Vec3f>
@@ -27,6 +30,11 @@ namespace DetourNavigator
         return osg::Vec3f(values[0], values[1], values[2]);
     }
 
+    inline osg::Vec3f makeOsgVec3f(const btVector3& value)
+    {
+        return osg::Vec3f(value.x(), value.y(), value.z());
+    }
+
     inline bool inRange(const osg::Vec3f& v1, const osg::Vec3f& v2, const float r, const float h)
     {
         const auto d = v2 - v1;
@@ -217,6 +225,7 @@ namespace DetourNavigator
         OPENMW_CHECK_DT_STATUS(navMeshQuery.init(&navMesh, settings.mMaxNavMeshQueryNodes));
 
         dtQueryFilter queryFilter;
+        queryFilter.setIncludeFlags(Flag_swim | Flag_walk);
 
         dtPolyRef startRef = 0;
         osg::Vec3f startPolygonPosition;
diff --git a/components/detournavigator/flags.hpp b/components/detournavigator/flags.hpp
index 21a1d7694c..38c0f13f6a 100644
--- a/components/detournavigator/flags.hpp
+++ b/components/detournavigator/flags.hpp
@@ -9,6 +9,7 @@ namespace DetourNavigator
     {
         Flag_none = 0,
         Flag_walk = 1 << 0,
+        Flag_swim = 1 << 1,
     };
 }
 
diff --git a/components/detournavigator/gettilespositions.hpp b/components/detournavigator/gettilespositions.hpp
index b52984452a..86ce77402d 100644
--- a/components/detournavigator/gettilespositions.hpp
+++ b/components/detournavigator/gettilespositions.hpp
@@ -51,6 +51,23 @@ namespace DetourNavigator
 
         getTilesPositions(makeOsgVec3f(aabbMin), makeOsgVec3f(aabbMax), settings, std::forward<Callback>(callback));
     }
+
+    template <class Callback>
+    void getTilesPositions(const int cellSize, const btTransform& transform,
+        const Settings& settings, Callback&& callback)
+    {
+        const auto halfCellSize = cellSize / 2;
+        auto aabbMin = transform(btVector3(-halfCellSize, -halfCellSize, 0));
+        auto aabbMax = transform(btVector3(halfCellSize, halfCellSize, 0));
+
+        aabbMin.setX(std::min(aabbMin.x(), aabbMax.x()));
+        aabbMin.setY(std::min(aabbMin.y(), aabbMax.y()));
+
+        aabbMax.setX(std::max(aabbMin.x(), aabbMax.x()));
+        aabbMax.setY(std::max(aabbMin.y(), aabbMax.y()));
+
+        getTilesPositions(makeOsgVec3f(aabbMin), makeOsgVec3f(aabbMax), settings, std::forward<Callback>(callback));
+    }
 }
 
 #endif
diff --git a/components/detournavigator/makenavmesh.cpp b/components/detournavigator/makenavmesh.cpp
index 454b88f9ea..71e8881683 100644
--- a/components/detournavigator/makenavmesh.cpp
+++ b/components/detournavigator/makenavmesh.cpp
@@ -15,6 +15,7 @@
 #include <Recast.h>
 #include <RecastAlloc.h>
 
+#include <algorithm>
 #include <iomanip>
 #include <limits>
 
@@ -64,6 +65,41 @@ namespace
         {}
     };
 
+    osg::Vec3f makeOsgVec3f(const btVector3& value)
+    {
+        return osg::Vec3f(value.x(), value.y(), value.z());
+    }
+
+    struct WaterBounds
+    {
+        osg::Vec3f mMin;
+        osg::Vec3f mMax;
+    };
+
+    WaterBounds getWaterBounds(const RecastMesh::Water& water, const Settings& settings,
+        const osg::Vec3f& agentHalfExtents)
+    {
+        if (water.mCellSize == std::numeric_limits<int>::max())
+        {
+            const auto transform = getSwimLevelTransform(settings, water.mTransform, agentHalfExtents.z());
+            const auto min = toNavMeshCoordinates(settings, makeOsgVec3f(transform(btVector3(-1, -1, 0))));
+            const auto max = toNavMeshCoordinates(settings, makeOsgVec3f(transform(btVector3(1, 1, 0))));
+            return WaterBounds {
+                osg::Vec3f(-std::numeric_limits<float>::max(), min.y(), -std::numeric_limits<float>::max()),
+                osg::Vec3f(std::numeric_limits<float>::max(), max.y(), std::numeric_limits<float>::max())
+            };
+        }
+        else
+        {
+            const auto transform = getSwimLevelTransform(settings, water.mTransform, agentHalfExtents.z());
+            const auto halfCellSize = water.mCellSize / 2.0f;
+            return WaterBounds {
+                toNavMeshCoordinates(settings, makeOsgVec3f(transform(btVector3(-halfCellSize, -halfCellSize, 0)))),
+                toNavMeshCoordinates(settings, makeOsgVec3f(transform(btVector3(halfCellSize, halfCellSize, 0))))
+            };
+        }
+    }
+
     NavMeshData makeNavMeshTileData(const osg::Vec3f& agentHalfExtents, const RecastMesh& recastMesh,
         const int tileX, const int tileY, const osg::Vec3f& boundsMin, const osg::Vec3f& boundsMax,
         const Settings& settings)
@@ -156,6 +192,56 @@ namespace
             }
         }
 
+        {
+            const std::array<unsigned char, 2> areas {{AreaType_water, AreaType_water}};
+
+            for (const auto& water : recastMesh.getWater())
+            {
+                const auto bounds = getWaterBounds(water, settings, agentHalfExtents);
+
+                const osg::Vec2f tileBoundsMin(
+                    std::min(config.bmax[0], std::max(config.bmin[0], bounds.mMin.x())),
+                    std::min(config.bmax[2], std::max(config.bmin[2], bounds.mMin.z()))
+                );
+                const osg::Vec2f tileBoundsMax(
+                    std::min(config.bmax[0], std::max(config.bmin[0], bounds.mMax.x())),
+                    std::min(config.bmax[2], std::max(config.bmin[2], bounds.mMax.z()))
+                );
+
+                if (tileBoundsMax == tileBoundsMin)
+                    continue;
+
+                const std::array<osg::Vec3f, 4> vertices {{
+                    osg::Vec3f(tileBoundsMin.x(), bounds.mMin.y(), tileBoundsMin.y()),
+                    osg::Vec3f(tileBoundsMin.x(), bounds.mMin.y(), tileBoundsMax.y()),
+                    osg::Vec3f(tileBoundsMax.x(), bounds.mMin.y(), tileBoundsMax.y()),
+                    osg::Vec3f(tileBoundsMax.x(), bounds.mMin.y(), tileBoundsMin.y()),
+                }};
+
+                std::array<float, 4 * 3> convertedVertices;
+                auto convertedVerticesIt = convertedVertices.begin();
+
+                for (const auto& vertex : vertices)
+                    convertedVerticesIt = std::copy(vertex.ptr(), vertex.ptr() + 3, convertedVerticesIt);
+
+                const std::array<int, 6> indices {{
+                    0, 1, 2,
+                    0, 2, 3,
+                }};
+
+                OPENMW_CHECK_DT_RESULT(rcRasterizeTriangles(
+                    &context,
+                    convertedVertices.data(),
+                    static_cast<int>(convertedVertices.size() / 3),
+                    indices.data(),
+                    areas.data(),
+                    static_cast<int>(areas.size()),
+                    solid,
+                    config.walkableClimb
+                ));
+            }
+        }
+
         rcFilterLowHangingWalkableObstacles(&context, config.walkableClimb, solid);
         rcFilterLedgeSpans(&context, config.walkableHeight, config.walkableClimb, solid);
         rcFilterWalkableLowHeightSpans(&context, config.walkableHeight, solid);
@@ -187,8 +273,12 @@ namespace
         }
 
         for (int i = 0; i < polyMesh.npolys; ++i)
+        {
             if (polyMesh.areas[i] == AreaType_ground)
                 polyMesh.flags[i] = Flag_walk;
+            else if (polyMesh.areas[i] == AreaType_water)
+                polyMesh.flags[i] = Flag_swim;
+        }
 
         dtNavMeshCreateParams params;
         params.verts = polyMesh.verts;
@@ -302,8 +392,15 @@ namespace DetourNavigator
             return removeTile();
         }
 
-        const auto& boundsMin = recastMesh->getBoundsMin();
-        const auto& boundsMax = recastMesh->getBoundsMax();
+        auto boundsMin = recastMesh->getBoundsMin();
+        auto boundsMax = recastMesh->getBoundsMax();
+
+        for (const auto& water : recastMesh->getWater())
+        {
+            const auto bounds = getWaterBounds(water, settings, agentHalfExtents);
+            boundsMin.y() = std::min(boundsMin.y(), bounds.mMin.y());
+            boundsMax.y() = std::max(boundsMax.y(), bounds.mMax.y());
+        }
 
         if (boundsMin == boundsMax)
         {
diff --git a/components/detournavigator/makenavmesh.hpp b/components/detournavigator/makenavmesh.hpp
index cc9e6d8559..7a60152d71 100644
--- a/components/detournavigator/makenavmesh.hpp
+++ b/components/detournavigator/makenavmesh.hpp
@@ -9,7 +9,6 @@
 #include <osg/Vec3f>
 
 #include <memory>
-#include <set>
 
 class dtNavMesh;
 
diff --git a/components/detournavigator/navigator.cpp b/components/detournavigator/navigator.cpp
index f6ead7c7db..359a9a316e 100644
--- a/components/detournavigator/navigator.cpp
+++ b/components/detournavigator/navigator.cpp
@@ -71,9 +71,24 @@ namespace DetourNavigator
     {
         bool result = mNavMeshManager.removeObject(id);
         const auto avoid = mAvoidIds.find(id);
-        if (avoid == mAvoidIds.end())
-            return result;
-        return mNavMeshManager.removeObject(avoid->second) || result;
+        if (avoid != mAvoidIds.end())
+            result = mNavMeshManager.removeObject(avoid->second) || result;
+        const auto water = mWaterIds.find(id);
+        if (water != mWaterIds.end())
+            result = mNavMeshManager.removeObject(water->second) || result;
+        return result;
+    }
+
+    bool Navigator::addWater(const osg::Vec2i& cellPosition, const int cellSize, const btScalar level,
+        const btTransform& transform)
+    {
+        return mNavMeshManager.addWater(cellPosition, cellSize,
+            btTransform(transform.getBasis(), btVector3(transform.getOrigin().x(), transform.getOrigin().y(), level)));
+    }
+
+    bool Navigator::removeWater(const osg::Vec2i& cellPosition)
+    {
+        return mNavMeshManager.removeWater(cellPosition);
     }
 
     void Navigator::update(const osg::Vec3f& playerPosition)
@@ -97,13 +112,23 @@ namespace DetourNavigator
         return mSettings;
     }
 
-    void Navigator::updateAvoidShapeId(std::size_t id, std::size_t avoidId)
+    void Navigator::updateAvoidShapeId(const std::size_t id, const std::size_t avoidId)
     {
-        auto inserted = mAvoidIds.insert(std::make_pair(id, avoidId));
+        updateId(id, avoidId, mWaterIds);
+    }
+
+    void Navigator::updateWaterShapeId(const std::size_t id, const std::size_t waterId)
+    {
+        updateId(id, waterId, mWaterIds);
+    }
+
+    void Navigator::updateId(const std::size_t id, const std::size_t updateId, std::unordered_map<std::size_t, std::size_t>& ids)
+    {
+        auto inserted = ids.insert(std::make_pair(id, updateId));
         if (!inserted.second)
         {
             mNavMeshManager.removeObject(inserted.first->second);
-            inserted.second = avoidId;
+            inserted.second = updateId;
         }
     }
 }
diff --git a/components/detournavigator/navigator.hpp b/components/detournavigator/navigator.hpp
index 0f82bd7abe..b063975254 100644
--- a/components/detournavigator/navigator.hpp
+++ b/components/detournavigator/navigator.hpp
@@ -37,6 +37,11 @@ namespace DetourNavigator
 
         bool removeObject(std::size_t id);
 
+        bool addWater(const osg::Vec2i& cellPosition, const int cellSize, const btScalar level,
+            const btTransform& transform);
+
+        bool removeWater(const osg::Vec2i& cellPosition);
+
         void update(const osg::Vec3f& playerPosition);
 
         void wait();
@@ -59,8 +64,11 @@ namespace DetourNavigator
         NavMeshManager mNavMeshManager;
         std::map<osg::Vec3f, std::size_t> mAgents;
         std::unordered_map<std::size_t, std::size_t> mAvoidIds;
+        std::unordered_map<std::size_t, std::size_t> mWaterIds;
 
-        void updateAvoidShapeId(std::size_t id, std::size_t avoidId);
+        void updateAvoidShapeId(const std::size_t id, const std::size_t avoidId);
+        void updateWaterShapeId(const std::size_t id, const std::size_t waterId);
+        void updateId(const std::size_t id, const std::size_t waterId, std::unordered_map<std::size_t, std::size_t>& ids);
     };
 }
 
diff --git a/components/detournavigator/navmeshmanager.cpp b/components/detournavigator/navmeshmanager.cpp
index 265ef749f5..bfca44f794 100644
--- a/components/detournavigator/navmeshmanager.cpp
+++ b/components/detournavigator/navmeshmanager.cpp
@@ -58,6 +58,23 @@ namespace DetourNavigator
         return true;
     }
 
+    bool NavMeshManager::addWater(const osg::Vec2i& cellPosition, const int cellSize, const btTransform& transform)
+    {
+        if (!mRecastMeshManager.addWater(cellPosition, cellSize, transform))
+            return false;
+        addChangedTiles(cellSize, transform, ChangeType::add);
+        return true;
+    }
+
+    bool NavMeshManager::removeWater(const osg::Vec2i& cellPosition)
+    {
+        const auto water = mRecastMeshManager.removeWater(cellPosition);
+        if (!water)
+            return false;
+        addChangedTiles(water->mCellSize, water->mTransform, ChangeType::remove);
+        return true;
+    }
+
     void NavMeshManager::addAgent(const osg::Vec3f& agentHalfExtents)
     {
         auto cached = mCache.find(agentHalfExtents);
@@ -75,9 +92,7 @@ namespace DetourNavigator
 
     void NavMeshManager::update(osg::Vec3f playerPosition, const osg::Vec3f& agentHalfExtents)
     {
-        playerPosition *= mSettings.mRecastScaleFactor;
-        std::swap(playerPosition.y(), playerPosition.z());
-        const auto playerTile = getTilePosition(mSettings, playerPosition);
+        const auto playerTile = getTilePosition(mSettings, toNavMeshCoordinates(mSettings, playerPosition));
         if (mLastRecastMeshManagerRevision >= mRecastMeshManager.getRevision() && mPlayerTile
                 && *mPlayerTile == playerTile)
             return;
@@ -140,20 +155,36 @@ namespace DetourNavigator
     }
 
     void NavMeshManager::addChangedTiles(const btCollisionShape& shape, const btTransform& transform,
-                                         const ChangeType changeType)
+            const ChangeType changeType)
     {
-        getTilesPositions(shape, transform, mSettings, [&] (const TilePosition& v) {
-            for (const auto& cached : mCache)
-                if (cached.second)
-                {
-                    auto& tiles = mChangedTiles[cached.first];
-                    auto tile = tiles.find(v);
-                    if (tile == tiles.end())
-                        tiles.insert(std::make_pair(v, changeType));
-                    else
-                        tile->second = addChangeType(tile->second, changeType);
-                }
-        });
+        getTilesPositions(shape, transform, mSettings,
+            [&] (const TilePosition& v) { addChangedTile(v, changeType); });
+    }
+
+    void NavMeshManager::addChangedTiles(const int cellSize, const btTransform& transform,
+            const ChangeType changeType)
+    {
+        if (cellSize == std::numeric_limits<int>::max())
+            return;
+
+        getTilesPositions(cellSize, transform, mSettings,
+            [&] (const TilePosition& v) { addChangedTile(v, changeType); });
+    }
+
+    void NavMeshManager::addChangedTile(const TilePosition& tilePosition, const ChangeType changeType)
+    {
+        for (const auto& cached : mCache)
+        {
+            if (cached.second)
+            {
+                auto& tiles = mChangedTiles[cached.first];
+                auto tile = tiles.find(tilePosition);
+                if (tile == tiles.end())
+                    tiles.insert(std::make_pair(tilePosition, changeType));
+                else
+                    tile->second = addChangeType(tile->second, changeType);
+            }
+        }
     }
 
     const std::shared_ptr<NavMeshCacheItem>& NavMeshManager::getCached(const osg::Vec3f& agentHalfExtents) const
diff --git a/components/detournavigator/navmeshmanager.hpp b/components/detournavigator/navmeshmanager.hpp
index 25ee305c4f..6636402bf0 100644
--- a/components/detournavigator/navmeshmanager.hpp
+++ b/components/detournavigator/navmeshmanager.hpp
@@ -7,8 +7,6 @@
 
 #include <BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h>
 
-#include <BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h>
-
 #include <osg/Vec3f>
 
 #include <map>
@@ -33,6 +31,10 @@ namespace DetourNavigator
 
         void addAgent(const osg::Vec3f& agentHalfExtents);
 
+        bool addWater(const osg::Vec2i& cellPosition, const int cellSize, const btTransform& transform);
+
+        bool removeWater(const osg::Vec2i& cellPosition);
+
         void reset(const osg::Vec3f& agentHalfExtents);
 
         void update(osg::Vec3f playerPosition, const osg::Vec3f& agentHalfExtents);
@@ -55,6 +57,10 @@ namespace DetourNavigator
 
         void addChangedTiles(const btCollisionShape& shape, const btTransform& transform, const ChangeType changeType);
 
+        void addChangedTiles(const int cellSize, const btTransform& transform, const ChangeType changeType);
+
+        void addChangedTile(const TilePosition& tilePosition, const ChangeType changeType);
+
         const std::shared_ptr<NavMeshCacheItem>& getCached(const osg::Vec3f& agentHalfExtents) const;
     };
 }
diff --git a/components/detournavigator/recastmesh.cpp b/components/detournavigator/recastmesh.cpp
index 5a339d3427..b4897d14aa 100644
--- a/components/detournavigator/recastmesh.cpp
+++ b/components/detournavigator/recastmesh.cpp
@@ -7,10 +7,11 @@
 namespace DetourNavigator
 {
     RecastMesh::RecastMesh(std::vector<int> indices, std::vector<float> vertices,
-                           std::vector<AreaType> areaTypes, const Settings& settings)
+                           std::vector<AreaType> areaTypes, std::vector<Water> water, const Settings& settings)
         : mIndices(std::move(indices))
         , mVertices(std::move(vertices))
         , mAreaTypes(std::move(areaTypes))
+        , mWater(std::move(water))
         , mChunkyTriMesh(mVertices, mIndices, mAreaTypes, settings.mTrianglesPerChunk)
     {
         if (getTrianglesCount() != mAreaTypes.size())
diff --git a/components/detournavigator/recastmesh.hpp b/components/detournavigator/recastmesh.hpp
index 2e31cd27d2..12dc73e488 100644
--- a/components/detournavigator/recastmesh.hpp
+++ b/components/detournavigator/recastmesh.hpp
@@ -9,6 +9,8 @@
 
 #include <osg/Vec3f>
 
+#include <LinearMath/btTransform.h>
+
 namespace DetourNavigator
 {
     struct Settings;
@@ -16,8 +18,14 @@ namespace DetourNavigator
     class RecastMesh
     {
     public:
+        struct Water
+        {
+            int mCellSize;
+            btTransform mTransform;
+        };
+
         RecastMesh(std::vector<int> indices, std::vector<float> vertices,
-                   std::vector<AreaType> areaTypes, const Settings& settings);
+                   std::vector<AreaType> areaTypes, std::vector<Water> water, const Settings& settings);
 
         const std::vector<int>& getIndices() const
         {
@@ -34,6 +42,11 @@ namespace DetourNavigator
             return mAreaTypes;
         }
 
+        const std::vector<Water>& getWater() const
+        {
+            return mWater;
+        }
+
         std::size_t getVerticesCount() const
         {
             return mVertices.size() / 3;
@@ -63,6 +76,7 @@ namespace DetourNavigator
         std::vector<int> mIndices;
         std::vector<float> mVertices;
         std::vector<AreaType> mAreaTypes;
+        std::vector<Water> mWater;
         ChunkyTriMesh mChunkyTriMesh;
         osg::Vec3f mBoundsMin;
         osg::Vec3f mBoundsMax;
diff --git a/components/detournavigator/recastmeshbuilder.cpp b/components/detournavigator/recastmeshbuilder.cpp
index 23a8bb83e6..3e87aa34b7 100644
--- a/components/detournavigator/recastmeshbuilder.cpp
+++ b/components/detournavigator/recastmeshbuilder.cpp
@@ -82,19 +82,16 @@ namespace DetourNavigator
 
     void RecastMeshBuilder::addObject(const btBoxShape& shape, const btTransform& transform, const AreaType areaType)
     {
-        const auto indexOffset = int(mVertices.size() / 3);
+        const auto indexOffset = static_cast<int>(mVertices.size() / 3);
 
-        for (int vertex = 0; vertex < shape.getNumVertices(); ++vertex)
+        for (int vertex = 0, count = shape.getNumVertices(); vertex < count; ++vertex)
         {
             btVector3 position;
             shape.getVertex(vertex, position);
             addVertex(transform(position));
         }
 
-        for (int vertex = 0; vertex < 12; ++vertex)
-            mAreaTypes.push_back(areaType);
-
-        static const std::array<int, 36> indices {{
+        const std::array<int, 36> indices {{
             0, 2, 3,
             3, 1, 0,
             0, 4, 6,
@@ -111,11 +108,18 @@ namespace DetourNavigator
 
         std::transform(indices.begin(), indices.end(), std::back_inserter(mIndices),
             [&] (int index) { return index + indexOffset; });
+
+        std::generate_n(std::back_inserter(mAreaTypes), 12, [=] { return areaType; });
+    }
+
+    void RecastMeshBuilder::addWater(const int cellSize, const btTransform& transform)
+    {
+        mWater.push_back(RecastMesh::Water {cellSize, transform});
     }
 
     std::shared_ptr<RecastMesh> RecastMeshBuilder::create() const
     {
-        return std::make_shared<RecastMesh>(mIndices, mVertices, mAreaTypes, mSettings);
+        return std::make_shared<RecastMesh>(mIndices, mVertices, mAreaTypes, mWater, mSettings);
     }
 
     void RecastMeshBuilder::reset()
@@ -123,6 +127,7 @@ namespace DetourNavigator
         mIndices.clear();
         mVertices.clear();
         mAreaTypes.clear();
+        mWater.clear();
     }
 
     void RecastMeshBuilder::addObject(const btConcaveShape& shape, const btTransform& transform,
diff --git a/components/detournavigator/recastmeshbuilder.hpp b/components/detournavigator/recastmeshbuilder.hpp
index 2210933627..af0565cabd 100644
--- a/components/detournavigator/recastmeshbuilder.hpp
+++ b/components/detournavigator/recastmeshbuilder.hpp
@@ -4,14 +4,17 @@
 #include "recastmesh.hpp"
 #include "tilebounds.hpp"
 
+#include <LinearMath/btTransform.h>
+
+#include <osg/Vec2f>
+#include <osg/Vec2i>
+
 class btBoxShape;
 class btCollisionShape;
 class btCompoundShape;
 class btConcaveShape;
 class btHeightfieldTerrainShape;
-class btTransform;
 class btTriangleCallback;
-class btVector3;
 
 namespace DetourNavigator
 {
@@ -30,6 +33,8 @@ namespace DetourNavigator
 
         void addObject(const btBoxShape& shape, const btTransform& transform, const AreaType areaType);
 
+        void addWater(const int mCellSize, const btTransform& transform);
+
         std::shared_ptr<RecastMesh> create() const;
 
         void reset();
@@ -40,6 +45,7 @@ namespace DetourNavigator
         std::vector<int> mIndices;
         std::vector<float> mVertices;
         std::vector<AreaType> mAreaTypes;
+        std::vector<RecastMesh::Water> mWater;
 
         void addObject(const btConcaveShape& shape, const btTransform& transform, btTriangleCallback&& callback);
 
diff --git a/components/detournavigator/recastmeshmanager.cpp b/components/detournavigator/recastmeshmanager.cpp
index d511891942..cabde7fdf8 100644
--- a/components/detournavigator/recastmeshmanager.cpp
+++ b/components/detournavigator/recastmeshmanager.cpp
@@ -42,6 +42,26 @@ namespace DetourNavigator
         return result;
     }
 
+    bool RecastMeshManager::addWater(const osg::Vec2i& cellPosition, const int cellSize,
+        const btTransform& transform)
+    {
+        if (!mWater.insert(std::make_pair(cellPosition, Water {cellSize, transform})).second)
+            return false;
+        mShouldRebuild = true;
+        return true;
+    }
+
+    boost::optional<RecastMeshManager::Water> RecastMeshManager::removeWater(const osg::Vec2i& cellPosition)
+    {
+        const auto water = mWater.find(cellPosition);
+        if (water == mWater.end())
+            return boost::none;
+        mShouldRebuild = true;
+        const auto result = water->second;
+        mWater.erase(water);
+        return result;
+    }
+
     std::shared_ptr<RecastMesh> RecastMeshManager::getMesh()
     {
         rebuild();
@@ -58,6 +78,8 @@ namespace DetourNavigator
         if (!mShouldRebuild)
             return;
         mMeshBuilder.reset();
+        for (const auto& v : mWater)
+            mMeshBuilder.addWater(v.second.mCellSize, v.second.mTransform);
         for (const auto& v : mObjects)
             mMeshBuilder.addObject(v.second.getShape(), v.second.getTransform(), v.second.getAreaType());
         mShouldRebuild = false;
diff --git a/components/detournavigator/recastmeshmanager.hpp b/components/detournavigator/recastmeshmanager.hpp
index 7900592950..c4391b6821 100644
--- a/components/detournavigator/recastmeshmanager.hpp
+++ b/components/detournavigator/recastmeshmanager.hpp
@@ -6,8 +6,11 @@
 
 #include <LinearMath/btTransform.h>
 
+#include <osg/Vec2i>
+
 #include <boost/optional.hpp>
 
+#include <map>
 #include <unordered_map>
 
 class btCollisionShape;
@@ -23,6 +26,12 @@ namespace DetourNavigator
     class RecastMeshManager
     {
     public:
+        struct Water
+        {
+            int mCellSize;
+            btTransform mTransform;
+        };
+
         RecastMeshManager(const Settings& settings, const TileBounds& bounds);
 
         bool addObject(std::size_t id, const btCollisionShape& shape, const btTransform& transform,
@@ -30,6 +39,10 @@ namespace DetourNavigator
 
         bool updateObject(std::size_t id, const btTransform& transform, const AreaType areaType);
 
+        bool addWater(const osg::Vec2i& cellPosition, const int cellSize, const btTransform& transform);
+
+        boost::optional<Water> removeWater(const osg::Vec2i& cellPosition);
+
         boost::optional<RemovedRecastMeshObject> removeObject(std::size_t id);
 
         std::shared_ptr<RecastMesh> getMesh();
@@ -40,6 +53,7 @@ namespace DetourNavigator
         bool mShouldRebuild;
         RecastMeshBuilder mMeshBuilder;
         std::unordered_map<std::size_t, RecastMeshObject> mObjects;
+        std::map<osg::Vec2i, Water> mWater;
 
         void rebuild();
     };
diff --git a/components/detournavigator/settings.hpp b/components/detournavigator/settings.hpp
index 0d34ae7e95..ccfece3dae 100644
--- a/components/detournavigator/settings.hpp
+++ b/components/detournavigator/settings.hpp
@@ -19,6 +19,7 @@ namespace DetourNavigator
         float mMaxSimplificationError;
         float mMaxSlope;
         float mRecastScaleFactor;
+        float mSwimHeightScale;
         int mBorderSize;
         int mMaxEdgeLen;
         int mMaxNavMeshQueryNodes;
diff --git a/components/detournavigator/settingsutils.hpp b/components/detournavigator/settingsutils.hpp
index 8127536862..d96ea53cc2 100644
--- a/components/detournavigator/settingsutils.hpp
+++ b/components/detournavigator/settingsutils.hpp
@@ -6,6 +6,8 @@
 #include "tileposition.hpp"
 #include "tilebounds.hpp"
 
+#include <LinearMath/btTransform.h>
+
 #include <osg/Vec2f>
 #include <osg/Vec2i>
 #include <osg/Vec3f>
@@ -68,6 +70,20 @@ namespace DetourNavigator
     {
         return settings.mBorderSize * settings.mCellSize;
     }
+
+    inline float getSwimLevel(const Settings& settings, const float agentHalfExtentsZ)
+    {
+        return - settings.mSwimHeightScale * agentHalfExtentsZ;
+    }
+
+    inline btTransform getSwimLevelTransform(const Settings& settings, const btTransform& transform,
+        const float agentHalfExtentsZ)
+    {
+        return btTransform(
+            transform.getBasis(),
+            transform.getOrigin() + btVector3(0, 0, getSwimLevel(settings, agentHalfExtentsZ) - agentHalfExtentsZ)
+        );
+    }
 }
 
 #endif
diff --git a/components/detournavigator/tilecachedrecastmeshmanager.cpp b/components/detournavigator/tilecachedrecastmeshmanager.cpp
index f044b3c43e..164253f856 100644
--- a/components/detournavigator/tilecachedrecastmeshmanager.cpp
+++ b/components/detournavigator/tilecachedrecastmeshmanager.cpp
@@ -83,6 +83,80 @@ namespace DetourNavigator
         return result;
     }
 
+    bool TileCachedRecastMeshManager::addWater(const osg::Vec2i& cellPosition, const int cellSize,
+        const btTransform& transform)
+    {
+        const auto border = getBorderSize(mSettings);
+
+        auto& tilesPositions = mWaterTilesPositions[cellPosition];
+
+        bool result = false;
+
+        if (cellSize == std::numeric_limits<int>::max())
+        {
+            const std::lock_guard<std::mutex> lock(mTilesMutex);
+            for (auto& tile : mTiles)
+            {
+                if (tile.second.addWater(cellPosition, cellSize, transform))
+                {
+                    tilesPositions.push_back(tile.first);
+                    result = true;
+                }
+            }
+        }
+        else
+        {
+            getTilesPositions(cellSize, transform, mSettings, [&] (const TilePosition& tilePosition)
+                {
+                    std::unique_lock<std::mutex> lock(mTilesMutex);
+                    auto tile = mTiles.find(tilePosition);
+                    if (tile == mTiles.end())
+                    {
+                        auto tileBounds = makeTileBounds(mSettings, tilePosition);
+                        tileBounds.mMin -= osg::Vec2f(border, border);
+                        tileBounds.mMax += osg::Vec2f(border, border);
+                        tile = mTiles.insert(std::make_pair(tilePosition,
+                                CachedRecastMeshManager(mSettings, tileBounds))).first;
+                    }
+                    if (tile->second.addWater(cellPosition, cellSize, transform))
+                    {
+                        lock.unlock();
+                        tilesPositions.push_back(tilePosition);
+                        result = true;
+                    }
+                });
+        }
+
+        if (result)
+            ++mRevision;
+
+        return result;
+    }
+
+    boost::optional<RecastMeshManager::Water> TileCachedRecastMeshManager::removeWater(const osg::Vec2i& cellPosition)
+    {
+        const auto object = mWaterTilesPositions.find(cellPosition);
+        if (object == mWaterTilesPositions.end())
+            return boost::none;
+        boost::optional<RecastMeshManager::Water> result;
+        for (const auto& tilePosition : object->second)
+        {
+            std::unique_lock<std::mutex> lock(mTilesMutex);
+            const auto tile = mTiles.find(tilePosition);
+            if (tile == mTiles.end())
+                continue;
+            const auto tileResult = tile->second.removeWater(cellPosition);
+            if (tile->second.isEmpty())
+                mTiles.erase(tile);
+            lock.unlock();
+            if (tileResult && !result)
+                result = tileResult;
+        }
+        if (result)
+            ++mRevision;
+        return result;
+    }
+
     std::shared_ptr<RecastMesh> TileCachedRecastMeshManager::getMesh(const TilePosition& tilePosition)
     {
         const std::lock_guard<std::mutex> lock(mTilesMutex);
diff --git a/components/detournavigator/tilecachedrecastmeshmanager.hpp b/components/detournavigator/tilecachedrecastmeshmanager.hpp
index 32b06eadd6..f67d2c3922 100644
--- a/components/detournavigator/tilecachedrecastmeshmanager.hpp
+++ b/components/detournavigator/tilecachedrecastmeshmanager.hpp
@@ -21,6 +21,10 @@ namespace DetourNavigator
 
         boost::optional<RemovedRecastMeshObject> removeObject(std::size_t id);
 
+        bool addWater(const osg::Vec2i& cellPosition, const int cellSize, const btTransform& transform);
+
+        boost::optional<RecastMeshManager::Water> removeWater(const osg::Vec2i& cellPosition);
+
         std::shared_ptr<RecastMesh> getMesh(const TilePosition& tilePosition);
 
         bool hasTile(const TilePosition& tilePosition);
@@ -40,6 +44,7 @@ namespace DetourNavigator
         std::mutex mTilesMutex;
         std::map<TilePosition, CachedRecastMeshManager> mTiles;
         std::unordered_map<std::size_t, std::vector<TilePosition>> mObjectsTilesPositions;
+        std::map<osg::Vec2i, std::vector<TilePosition>> mWaterTilesPositions;
         std::size_t mRevision = 0;
     };
 }