It is not unusual for homeowners who have household pets to have urine stains on their carpet. Pets will urinate on carpet as an act of territorial-ism, anxiety, or simply out of need. If your dog is not neutered, they will pee on everything and anything – including all furniture, curtains, shoes, and handbags in your house.

The color of pet urine and its staining potential will often depend on dietary habits and the age of the pet. Foods high in protein tend to produce a darker, more pungent and acidic urine. Foods higher in carbohydrates such as corn or oats produces more alkaline urine that is less likely to stain carpet and does not produce as potent an odor. Typically, because cat diets are richer in protein than dog diets, their urine will produce harsher odors and are more likely to cause stains.

Unlike dogs, cats do not urinate for territorial-ism. This behavioral pattern in male cats is accomplished by spraying. This urine product also contains the male hormone testosterone which makes it even more pungent than urine. Although spraying is typically done on a vertical surface (such as a couch) it could also conceivably come in contact with a carpet.
Another consideration is the age of the pet. The older the pet the more renal function diminishes, thus producing urine that contains more plasma proteins. Because less uric acid is secreted in this urine it is less likely to stain a carpet; however, it will produce an even stronger odor. In almost all cases cat urine is the worst perpetrator for pet stains.

The degree of staining from pet urine on a carpet will depend in part on the fiber type and dye method of the carpet. Solution dyed fibers will be the most resistant to urine stains with olefin fibers providing the greatest stain resistance. In most cases, stains created by urine tend to leave either a red tinge (by adding to the existing color) or a yellow tinge (by reducing existing color). In either case the shift in color is almost always permanent in nature. Although there are some commercially available products designed to remove urine they are only effective on fresh spots. Neutralizers and deodorizers offer only minimal help in removing urine and urine odors once it has set into the carpet and pad. Even the sub floor can become contaminated.