When it comes to getting rid of unpleasant household odors, cat urine is a formidable opponent. Once it's soaked into the carpeting or upholstery, the bacteria keeps on growing, creating that lingering ammonia smell and beckoning your cats to return to the same spot. While many commercial products can remove cat urine odor, a home remedy, like white vinegar mixed with water, is less expensive and can be more effective.
Use a Black Light
Cats who prefer carpeting or upholstered furniture to litter boxes rarely urinate in just one spot. Use a black light (pet supply stores sell them) to find all the places where your cat has urinated.
Cleaning Carpeting and Upholstered Furniture
Make a solution of 50 percent white vinegar and 50 percent water. The acidity of the vinegar will neutralize the ammonia in the urine. Saturate all the areas where your cat urinated and allow them to air dry. Then cover them with a thick coating of baking soda.
Add a drop of dishwashing liquid, or 1/4 cup hydrogen peroxide, to a container of water. Peroxide will kill the bacteria that causes the ammonia smell. Pour either solution on the baking soda, work it into a paste and let it air dry. When the baking soda returns to powder, vacuum it up.
If the urine stains are old and especially stubborn, you might have to repeat this process several times.
After the areas are clean and dry, spray them with Feliway or sprinkle catnip on them. Feliway (see Resources) mimics the "friendly" pheromone in a cat's cheeks and discourages urine marking. Catnip, too, is a friendly scent.
Clothing, Stuffed Toys and Bedding
Add 1/4 cup of apple cider vinegar to laundry soap when washing urine-soaked clothing, stuffed toys and bedding. Using laundry soap with a strong, lingering scent could discourage the cat from urinating on the bedding or toys again.
Sprinkling catnip or spraying Feliway on beds will also discourage your cat from returning to the beds to urinate.
First wash the areas with any cleaning product that does not contain ammonia. With fresh water, wipe away the residue left by the cleaner. Repeat this process. Then spray the area with a solution of one part bleach to 10 parts water. After about 30 seconds, go over the area with a clean, damp cloth.
Clean the area with white vinegar and rinse thoroughly with warm water. After you blot the area dry, apply a stain- and odor-removing enzyme cleaner.
If the cats have done so much damage that the carpeting and padding need to be replaced, chances are the odor has also seeped into the subflooring. Clean and seal the subflooring before installing new carpet.
About your Cat
While urinating outside the litter box is often a behavior issue, physical problems can also cause inappropriate elimination. Cats with urinary tract infections may associate the litter box with pain and seek more comfortable places for their bathroom chores. Diabetes, hyperthyroidism and kidney failure can all cause older cats to have to urinate so frequently and in such volume they can't always get to their box.