diff --git a/apps/openmw/mwphysics/actor.cpp b/apps/openmw/mwphysics/actor.cpp
index 61022da28..9be34495e 100644
--- a/apps/openmw/mwphysics/actor.cpp
+++ b/apps/openmw/mwphysics/actor.cpp
@@ -47,7 +47,7 @@ Actor::Actor(const MWWorld::Ptr& ptr, osg::ref_ptr<const Resource::BulletShape>
     updateScale();
     updatePosition();
 
-    updateCollisionMask();
+    addCollisionMask(getCollisionMask());
 }
 
 Actor::~Actor()
@@ -70,15 +70,26 @@ void Actor::enableCollisionBody(bool collision)
     }
 }
 
+void Actor::addCollisionMask(int collisionMask)
+{
+    mCollisionWorld->addCollisionObject(mCollisionObject.get(), CollisionType_Actor, collisionMask);
+}
+
 void Actor::updateCollisionMask()
 {
     mCollisionWorld->removeCollisionObject(mCollisionObject.get());
+    addCollisionMask(getCollisionMask());
+}
+
+int Actor::getCollisionMask()
+{
     int collisionMask = CollisionType_World | CollisionType_HeightMap;
     if (mExternalCollisionMode)
         collisionMask |= CollisionType_Actor | CollisionType_Projectile | CollisionType_Door;
     if (mCanWaterWalk)
         collisionMask |= CollisionType_Water;
-    mCollisionWorld->addCollisionObject(mCollisionObject.get(), CollisionType_Actor, collisionMask);
+    return collisionMask;
+    
 }
 
 void Actor::updatePosition()
diff --git a/apps/openmw/mwphysics/actor.hpp b/apps/openmw/mwphysics/actor.hpp
index b238547e1..a0bf5bfc0 100644
--- a/apps/openmw/mwphysics/actor.hpp
+++ b/apps/openmw/mwphysics/actor.hpp
@@ -139,6 +139,8 @@ namespace MWPhysics
     private:
         /// Removes then re-adds the collision object to the dynamics world
         void updateCollisionMask();
+        void addCollisionMask(int collisionMask);
+        int getCollisionMask();
 
         bool mCanWaterWalk;
         bool mWalkingOnWater;
diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index 1a97fc6ff..f94ee14b6 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -1467,7 +1467,10 @@ namespace MWPhysics
         }
 
         if (!mWaterEnabled)
+        {
+            mWaterCollisionObject.reset();
             return;
+        }
 
         mWaterCollisionObject.reset(new btCollisionObject());
         mWaterCollisionShape.reset(new btStaticPlaneShape(btVector3(0,0,1), mWaterHeight));