diff --git a/src/world_diff.rs b/src/world_diff.rs
index 8980c770..1bebded7 100644
--- a/src/world_diff.rs
+++ b/src/world_diff.rs
@@ -131,7 +131,6 @@ impl WorldDiff {
 
         if world.is_free_storage_slot(&contract, &key) {
             self.written_storage_slots.add((contract, key));
-            self.read_storage_slots.add((contract, key));
 
             self.storage_refunds.push(WARM_WRITE_REFUND);
             self.pubdata_costs.push(0);