How to Get Cat Urine Smell Out of Concrete

Cat urine creates a stench that doesn't necessarily go away when it dries, as even the slightest bit of moisture causes the compounds within the urine to emit odors once again. Simply rinsing cat urine off the concrete garage floor or driveway isn't enough to get rid of the issue either, because concrete is porous and absorbs the urine. Cleaning the concrete a couple of different ways helps eliminate both the bacteria and the lingering uric acid from the urine, ultimately removing the odor.

If you spot a puddle on the concrete, it's easy enough to locate the exact source of the smell, but if it's already dry, it takes a little detective work. Shine an ultraviolet flashlight over the concrete with most of the lights off indoors, or when it's nearly dark out, if the stain is outdoors. Aim the flashlight within a few feet of the concrete for best results; if it's too far away, it won't be effective.

Urine glows under UV light, so you'll have no problem finding the pee. The glowing color may vary from blue to green or yellow. Circle the area with chalk so you know where to concentrate your cleaning efforts.

Enzymatic cleaners are great at removing uric acid and urine-related odors from concrete, but they work even better after treating the area with a trisodium phosphate (TSP) solution. TSP removes bacteria and many other substances from the urine that soaked into the concrete, allowing the enzymatic cleaner to focus on removing the uric acid. If you'd rather not use TSP, mix 2 parts vinegar to 1 part hot water instead.

Mix 1/2 cup TSP into 1 gallon of hot tap water. Wear gloves and eye protection and open all windows or doors if working indoors, such as in the garage. Pour some of the TSP mixture onto the urine stain and scrub it with a deck brush or a scrub brush. The urine odor gets stronger at this point as the uric acid crystals break down, so a deck brush helps keep your face out of the direct odor. Allow the solution to sit for 10 minutes or so, adding more as needed to ensure the area stays wet.

Pour clean hot water over the area and vacuum it with a wet/dry vac. Repeat the rinsing and vacuuming process at least twice more; each time, the odor should diminish a little more. Allow the concrete to dry a full day, as enzymatic cleaners work best when dry. If the concrete looks lighter in the treated area than in the surrounding areas, scrub the entire concrete surface with the same TSP solution.

Enzymatic cleaners such as the type sold in pet stores work better than the usual soap and water solutions when it comes to removing urine stains, because they use enzymes and live bacteria to break down the compounds within urine that cause odors. Shake the bottle of enzymatic cleaner and mix it according to the label's instructions; in some cases, this may require simply hooking it up to a garden hose. Scrub the area and let the solution soak in for at least 10 minutes or as directed on the label, applying more solution if the concrete starts to dry. Rinse only if directed to do so on the product label.