We love our pets, but accidents happen. Unfortunately, pet urine does not stay on the surface of the carpet. It always seeps down through the carpet pad and then all the way to the subfloor. You may not notice a smell of pet urine at first. But with repeated accidents over time the smell becomes very strong and usually requires padding and subfloor treatment to eliminate the odor. Just cleaning the carpet alone will not truly eliminate the odor. A standard surface cleaning will only produce a temporary cover-up scent.