diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -39,6 +39,7 @@
 #include "industry.h"
 #include "water_cmd.h"
 #include "landscape_cmd.h"
+#include "pathfinder/water_regions.h"
 
 #include "table/strings.h"
 
@@ -133,6 +134,9 @@ CommandCost CmdBuildShipDepot(DoCommandF
 	}
 
 	if (flags & DC_EXEC) {
+		InvalidateWaterRegion(tile);
+		InvalidateWaterRegion(tile2);
+
 		Depot *depot = new Depot(tile);
 		depot->build_date = TimerGameCalendar::date;
 
@@ -243,6 +247,7 @@ void MakeWaterKeepingClass(TileIndex til
 
 	/* Zero map array and terminate animation */
 	DoClearSquare(tile);
+	InvalidateWaterRegion(tile);
 
 	/* Maybe change to water */
 	switch (wc) {
@@ -340,6 +345,10 @@ static CommandCost DoBuildLock(TileIndex
 	}
 
 	if (flags & DC_EXEC) {
+		InvalidateWaterRegion(tile);
+		InvalidateWaterRegion(tile + delta);
+		InvalidateWaterRegion(tile - delta);
+
 		/* Update company infrastructure counts. */
 		Company *c = Company::GetIfValid(_current_company);
 		if (c != nullptr) {
@@ -482,6 +491,8 @@ CommandCost CmdBuildCanal(DoCommandFlag 
 		if (!water) cost.AddCost(ret);
 
 		if (flags & DC_EXEC) {
+			InvalidateWaterRegion(current_tile);
+
 			if (IsTileType(current_tile, MP_WATER) && IsCanal(current_tile)) {
 				Owner owner = GetTileOwner(current_tile);
 				if (Company::IsValidID(owner)) {
@@ -529,8 +540,11 @@ CommandCost CmdBuildCanal(DoCommandFlag 
 	}
 }
 
+
 static CommandCost ClearTile_Water(TileIndex tile, DoCommandFlag flags)
 {
+	if (flags & DC_EXEC) InvalidateWaterRegion(tile);
+
 	switch (GetWaterTileType(tile)) {
 		case WATER_TILE_CLEAR: {
 			if (flags & DC_NO_WATER) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);
@@ -1161,6 +1175,8 @@ void DoFloodTile(TileIndex target)
 	}
 
 	if (flooded) {
+		InvalidateWaterRegion(target);
+
 		/* Mark surrounding canal tiles dirty too to avoid glitches */
 		MarkCanalsAndRiversAroundDirty(target);