Urine deposited on carpet does not stay there, it penetrates the fibers and contaminates both the backing of the carpet and the flooring material below the carpet. Often, without your knowing, pets will urinate continually in the same general location. Urine odors can permeate from the floor, be it cement or wood, from the tack strip, and even from the framework of the house behind the walls.
As the urine dries, the liquid evaporates but the urine crystals become even more concentrated and pungent. Simple cleaning will not remove this odor. Until recently, there was not a product available that was effective at removing urine odors. When P.U.R.T.© contacts the source of the odor, it immediately begins a chemical reaction that destroys the urine odor.