diff --git a/src/landscape.cpp b/src/landscape.cpp
index 478bf6964d..6e02264f79 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -460,7 +460,7 @@ void DrawFoundation(TileInfo *ti, Foundation f)
 		if (!IsNonContinuousFoundation(f)) {
 			/* Lower part of foundation */
 			static constexpr SpriteBounds bounds{{}, {TILE_SIZE, TILE_SIZE, TILE_HEIGHT - 1}, {}};
-			AddSortableSpriteToDraw(leveled_base + (ti->tileh & ~SLOPE_STEEP), PAL_NONE, *ti, bounds);
+			AddSortableSpriteToDraw(leveled_base + RemoveSteepSlope(ti->tileh), PAL_NONE, *ti, bounds);
 		}
 
 		Corner highest_corner = GetHighestSlopeCorner(ti->tileh);
diff --git a/src/slope_func.h b/src/slope_func.h
index eaa3d0c762..38695c65d9 100644
--- a/src/slope_func.h
+++ b/src/slope_func.h
@@ -38,6 +38,16 @@ static constexpr inline bool IsSteepSlope(Slope s)
 	return (s & SLOPE_STEEP) != 0;
 }
 
+/**
+ * Removes a steep flag from a slope
+ * @param s A #Slope to get modified version of.
+ * @return The slope s without the steep flag.
+ */
+static constexpr Slope RemoveSteepSlope(Slope s)
+{
+	return s & ~SLOPE_STEEP;
+}
+
 /**
  * Checks for non-continuous slope on halftile foundations.
  *
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index 832f9f36ee..a3d81bd2f8 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -1074,9 +1074,8 @@ static bool IsRoadAllowedHere(Town *t, TileIndex tile, DiagDirection dir)
 		if (Chance16(1, 8)) {
 			CommandCost res = CMD_ERROR;
 			if (!_generating_world && Chance16(1, 10)) {
-				/* Note: Do not replace "^ SLOPE_ELEVATED" with ComplementSlope(). The slope might be steep. */
 				res = ExtractCommandCost(Command<Commands::TerraformLand>::Do({DoCommandFlag::Execute, DoCommandFlag::Auto, DoCommandFlag::NoWater},
-						tile, Chance16(1, 16) ? cur_slope : cur_slope ^ SLOPE_ELEVATED, false));
+						tile, Chance16(1, 16) ? cur_slope : ComplementSlope(RemoveSteepSlope(RemoveHalftileSlope(cur_slope))), false));
 			}
 			if (res.Failed() && Chance16(1, 3)) {
 				/* We can consider building on the slope, though. */
diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index 240cb2d69e..1681605dc3 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -1318,7 +1318,7 @@ void TileLoop_Water(TileIndex tile)
 				auto [slope_dest, z_dest] = GetFoundationSlope(dest);
 				if (z_dest > 0) continue;
 
-				if (!_flood_from_dirs[slope_dest & ~SLOPE_HALFTILE_MASK & ~SLOPE_STEEP].Test(ReverseDir(dir))) continue;
+				if (!_flood_from_dirs[RemoveSteepSlope(RemoveHalftileSlope(slope_dest))].Test(ReverseDir(dir))) continue;
 
 				DoFloodTile(dest);
 			}
@@ -1327,7 +1327,7 @@ void TileLoop_Water(TileIndex tile)
 		}
 
 		case FloodingBehaviour::DryOut: {
-			Slope slope_here = std::get<Slope>(GetFoundationSlope(tile)) & ~SLOPE_HALFTILE_MASK & ~SLOPE_STEEP;
+			Slope slope_here = RemoveHalftileSlope(RemoveSteepSlope(std::get<Slope>(GetFoundationSlope(tile))));
 			for (Direction dir : _flood_from_dirs[slope_here]) {
 				TileIndex dest = AddTileIndexDiffCWrap(tile, TileIndexDiffCByDir(dir));
 				/* Contrary to flooding, drying up does consider TileType::Void tiles. */
@@ -1365,9 +1365,9 @@ void ConvertGroundTilesIntoWaterTiles()
 					break;
 
 				default:
-					for (Direction dir : _flood_from_dirs[slope & ~SLOPE_STEEP]) {
+					for (Direction dir : _flood_from_dirs[RemoveSteepSlope(slope)]) {
 						TileIndex dest = TileAddByDir(tile, dir);
-						Slope slope_dest = GetTileSlope(dest) & ~SLOPE_STEEP;
+						Slope slope_dest = RemoveSteepSlope(GetTileSlope(dest));
 						if (slope_dest == SLOPE_FLAT || IsSlopeWithOneCornerRaised(slope_dest) || IsTileType(dest, TileType::Void)) {
 							MakeShore(tile);
 							break;