diff --git a/code/game/turfs/simulated.dm b/code/game/turfs/simulated.dm
index c02775c1c0a..f86a176f712 100644
--- a/code/game/turfs/simulated.dm
+++ b/code/game/turfs/simulated.dm
@@ -28,6 +28,15 @@
 	if (istype(A,/mob/living/carbon))
 		var/mob/living/carbon/M = A
 		if(M.lying)        return
+		dirt++
+		var/obj/effect/decal/cleanable/dirt/dirtoverlay = locate(/obj/effect/decal/cleanable/dirt, src)
+		if (dirt >= 30)
+			if (!dirtoverlay)
+				dirtoverlay = new/obj/effect/decal/cleanable/dirt(src)
+				dirtoverlay.alpha = 15
+			else if (dirt > 30)
+				dirtoverlay.alpha = min(dirtoverlay.alpha+20, 255)
+
 		if(istype(M, /mob/living/carbon/human))
 			var/mob/living/carbon/human/H = M
 			if(istype(H.shoes, /obj/item/clothing/shoes/clown_shoes))