Cat urine stains, left untreated, can be expensive to fix. Once the urine sets into the subflooring, it is near impossible to remove. The result is ruined subflooring, more cat accidents, and terrible odor.Keep pet urine cleaning supplies handy so you can nip this problem in the bud.ake sure the cleaner is so thickly applied that it gets down to the subflooring beneath the carpet. Enzymatic cleaners actually dissolve the urine, removing the odor that might attract your cat back to the same spot. Let air dry completely, then rinse with clean water and a rag.