diff --git a/src/newgrf_house.cpp b/src/newgrf_house.cpp
--- a/src/newgrf_house.cpp
+++ b/src/newgrf_house.cpp
@@ -25,7 +25,7 @@
 #include "safeguards.h"
 
 static BuildingCounts<uint32_t> _building_counts;
-static HouseClassMapping _class_mapping[HOUSE_CLASS_MAX];
+static std::array<HouseClassMapping, HOUSE_CLASS_MAX> _class_mapping;
 
 HouseOverrideManager _house_mngr(NEW_HOUSE_OFFSET, NUM_HOUSES, INVALID_HOUSE_ID);
 
@@ -72,6 +72,11 @@ uint32_t HouseResolverObject::GetDebugID
 	return HouseSpec::Get(this->house_scope.house_id)->grf_prop.local_id;
 }
 
+void ResetHouseClassIDs()
+{
+	_class_mapping = {};
+}
+
 HouseClassID AllocateHouseClassID(byte grf_class_id, uint32_t grfid)
 {
 	/* Start from 1 because 0 means that no class has been assigned. */