diff --git a/code/game/objects/structures/watercloset.dm b/code/game/objects/structures/watercloset.dm
index 892d85cd6e..0ffbb9f3ea 100644
--- a/code/game/objects/structures/watercloset.dm
+++ b/code/game/objects/structures/watercloset.dm
@@ -64,7 +64,7 @@
 			else
 				I.forceMove(drop_location())
 			to_chat(user, "<span class='notice'>You find [I] in the cistern.</span>")
-			w_items -= I.w_class
+			w_items = max(w_items - I.w_class, 0)
 	else
 		open = !open
 		update_icon()
@@ -115,6 +115,12 @@
 		secret.desc += "" //In case you want to add something to the item that spawns
 		contents += secret
 
+/obj/structure/toilet/secret/LateInitialize()
+	. = ..()
+	w_items = 0 //recalculate total weight thanks to the secret.
+	for(var/item/I in contents)
+		w_items += I.w_class
+
 /obj/structure/toilet/secret/low_loot
 	secret_type = /obj/effect/spawner/lootdrop/low_loot_toilet