diff --git a/src/object_cmd.cpp b/src/object_cmd.cpp
index 3d7812cbdb..30ee2825a5 100644
--- a/src/object_cmd.cpp
+++ b/src/object_cmd.cpp
@@ -115,6 +115,7 @@ void BuildObject(ObjectType type, TileIndex tile, CompanyID owner, Town *town, u
 	assert(o->town != nullptr);
 
 	TILE_AREA_LOOP(t, ta) {
+		if (IsWaterTile(t)) ClearNeighbourNonFloodingStates(t);
 		WaterClass wc = (IsWaterTile(t) ? GetWaterClass(t) : WATER_CLASS_INVALID);
 		/* Update company infrastructure counts for objects build on canals owned by nobody. */
 		if (wc == WATER_CLASS_CANAL && owner != OWNER_NONE && (IsTileOwner(tile, OWNER_NONE) || IsTileOwner(tile, OWNER_WATER))) {
diff --git a/src/tree_cmd.cpp b/src/tree_cmd.cpp
index 8de5888d70..edfc939dfd 100644
--- a/src/tree_cmd.cpp
+++ b/src/tree_cmd.cpp
@@ -99,6 +99,7 @@ static void PlantTreesOnTile(TileIndex tile, TreeType treetype, uint count, uint
 	switch (GetTileType(tile)) {
 		case MP_WATER:
 			ground = TREE_GROUND_SHORE;
+			ClearNeighbourNonFloodingStates(tile);
 			break;
 
 		case MP_CLEAR:
diff --git a/src/water.h b/src/water.h
index 27c3339c18..0ec972a3cd 100644
--- a/src/water.h
+++ b/src/water.h
@@ -24,6 +24,7 @@ enum FloodingBehaviour {
 };
 
 FloodingBehaviour GetFloodingBehaviour(TileIndex tile);
+void ClearNeighbourNonFloodingStates(TileIndex tile);
 
 void TileLoop_Water(TileIndex tile);
 bool FloodHalftile(TileIndex t);
diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index b83d95cbfa..8f813818e4 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -88,7 +88,7 @@ static void MarkCanalsAndRiversAroundDirty(TileIndex tile)
 	}
 }
 
-static void ClearNeighbourNonFloodingStates(TileIndex tile)
+void ClearNeighbourNonFloodingStates(TileIndex tile)
 {
 	for (Direction dir = DIR_BEGIN; dir < DIR_END; dir++) {
 		TileIndex dest = tile + TileOffsByDir(dir);
diff --git a/src/waypoint_cmd.cpp b/src/waypoint_cmd.cpp
index a5f76d4643..5aac1259cc 100644
--- a/src/waypoint_cmd.cpp
+++ b/src/waypoint_cmd.cpp
@@ -346,6 +346,7 @@ CommandCost CmdBuildBuoy(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 		MakeBuoy(tile, wp->index, GetWaterClass(tile));
 		CheckForDockingTile(tile);
 		MarkTileDirtyByTile(tile);
+		ClearNeighbourNonFloodingStates(tile);
 
 		wp->UpdateVirtCoord();
 		InvalidateWindowData(WC_WAYPOINT_VIEW, wp->index);