diff --git a/plow/PlowMain.c b/plow/PlowMain.c
index eed98001..ac2b333c 100644
--- a/plow/PlowMain.c
+++ b/plow/PlowMain.c
@@ -2051,6 +2051,10 @@ PlowAfterTech()
     TileTypeBitMask mask;
     TileType i, j;
 
+    /* Reset rules tables */
+    plowSearchRulesPtr = plowSearchRulesTbl;
+    plowCellRulesPtr = plowCellRulesTbl;
+
     /* Set the masks we will use for all the rules below */
     allButSpace = DBAllButSpaceAndDRCBits;
     allBits = DBAllTypeBits;