A dog or cat that weighs less than five pounds can produce more than 10 gallons of urine per year.
Animals are creatures of habit. They will continue to go back to the same area repeatedly.
Gravity pulls urine deposited on carpet into the backing, padding and sub-surface causing a far worse problem underneath carpet than on top. A 3 inch stain on the carpet could easily result in a 1 foot contaminated area underneath.
Deodorizers only cover up odors. Once they wear off, the original odor returns usually with a stale deodorant smell along with it.
Deodorizers (liquid, powders, sprays, etc.) are not government regulated nor are they required by law to perform as advertised. Many of these so-called odor control products are simply ineffective.
Carpet cleaning alone almost always does not remove pet odors.
Pet odor removal is a highly specialized service. Many carpet cleaners do not possess the knowledge to fully counteract pet odors.
Pet odors can temporarily cease during winter months only to return in the spring. This is due to the fact moisture (humidity) reactivates urine residues.