Cleaning Cat Urine from Concrete Floor

Cleaning Cat Urine from Concrete Floor

When everything is going well for your cat, she may happily pee at her litter box. On the other hand, where she is rebelling, she can be a very bad kitty peeing on the concrete whether it is in the garage, basement, pavement, or yard.

Cat urine is highly concentrated compared to the urine of humans and it can therefore also emit a strong odor. Once it seeped into the concrete, it may leave a permanent pungent and offensive smell that may even lead to respiratory problems in humans, including asthma and allergies.

The smell of ammonia can also stay muted after the urine dries, and may get activated once the concrete gets wet again. To eliminate this problem, you have to do a deep cleaning of the concrete to get it all out and seal the surface to prevent future seepage.

How to identify urine odor and stains in concrete

Usually, the stains made from cat urine on concrete are visible to the human eye. But there may be cases where there is no appearance of a stain and hence it is difficult to identify the location of the source of the odor. A helpful tool for finding cat urine is a U.V. light or black light. Hold it no more than three feet off the concrete as you scan the floor in sections.

If you shine the black light in a dark room, cat urine will glow yellow, blue, or green, making it easy to see exactly where you need to clean. Mark those areas for easy reference using chalk.

If the mentioned method fails, you may have to rely on your sense of smell. This may be a bit squeamish for others who have a sensitive nose and it may take longer, but this is still the most reliable method of identifying the odor.

Removing urine odor and stains on concrete

Removing urine odor and stains on concrete
Image: / Stella_E

Once you have identified the location of the urine, cleaning is the next step. Unsealed concrete may appear hard and impermeable, but it is actually like a hard sponge, with many tiny pores and urine that can soak deeply into the concrete. Traditional cleaning and scrubbing with water and soap may not suffice and you may need to resort to a strong solution for this problem.

Before using any treatment, make sure to remove and scrape off any old residue attached on the spot to make the process easier. Follow these tips below for removing urine odor and stains made on the concrete floor:

1.  Enzyme-based products to remove urine odor and stains

The reason that urine odor is so difficult to remove is because of the uric acid crystals found in urine. Any type of urine from mammals, whether it is human or cat urine, contains uric acid crystals, which can only be removed by using an enzyme-based cleaning product. The product must have the correct combination of enzymes and other ingredients to destroy the uric acid crystals and at the same time eliminate the bacteria surrounding the urine which causes the odor.

Be sure to follow the instructions for the product you choose. For the best results, cover the wet area to help avoid evaporation of the solution. This will give it more time to seep into the concrete. You might have to treat the area with a product more than once. Check the area again using a black light to see if you are successful in eliminating the problem.

2.  Use household items for the next step

If after using an enzymatic product and the problem is still there, then you can use household items for more effectiveness and help reduce the risk of staining and eliminate the odor source. If you currently do not have these items, you can always find them in stores near you or you can buy them online.


Vinegar is usually present in every household. It is also safe, chemical-free, and very good at killing bacteria. Start by mixing 2 parts of vinegar and 1 part of hot water, pour and scrub it on the affected area but do not rinse it right away. Just like using the enzymatic product, cover the area and let it soak for 24 hours. When using vinegar, remember to be careful on using as it can react with the alkaline in the concrete and create unwanted marks or patterns. Test it first in a small area to find out.

 Use household items for the next step
Image: / Pat_Hastings

Hydrogen Peroxide with a mix of baking soda and liquid soap

Using this mixture may get you good results but it takes a few days to complete the treatment. Mix 2 drops of liquid soap, 2 teaspoons of baking soda and 2 cups of hydrogen peroxide in a bowl and stir it gently until the baking soda is dissolved. Let the mixture sit on the stained area for 24 hours and cover it to allow natural evaporation. You may have to repeat this between 3 to 5 days to ensure the urine is completely dissolved.

TSP – a heavy-duty solution

Before wanting to use TSP (Trisodium Phosphate), it is best to know that this item is highly corrosive and damaging to the skin. Wear protective clothing to ensure no contact between the chemical and your skin like rubber gloves, a mask to cover your nose, and eye protection.

After scrubbing the area clean to remove unwanted residues, pour ½ cup of TSP in 1 gallon of hot water, apply this on the stained area, making sure to work only a small area (no more than three square feet) at a time, as it evaporates quickly.  Brush it off gently using a short-bristled nylon brush or any tough brush. You will notice that the smell grows strong as you continue the process. Leave the solution to stay for at least 10 minutes and apply more if it dries sooner.

To rinse the TSP on the concrete floor, pour very hot water then vacuum it up to suck up any remaining residue of urine in the concrete. Allow 24 hours for the concrete to be completely dry. Also. you may want to do this process twice or more for heavily affected areas.

 3.  Do NOT use bleaching products

You might think of using bleach to clean the concrete floors after removing the stain on your concrete floor, but bleach won’t kill the odor. It simply disinfects. Bleach is harmful to breathe, and it’s toxic for your pets, too.

4.  Do NOT use soap and detergent with Ammonia

Of all the things you can use to clean your cat’s pee, Ammonia is top on the list of things not to use. Since urine has an ammonia odor, adding more will just make the smell worse and your cat is likely to return to that area because she is attracted to the ammonia smell. Remember that you should NOT combine bleach with ammonia. Inhaling the fumes can be very dangerous.

If all fails…

So, you tried everything above and none has worked? You might think of giving up but you still have one last hope to save your concrete floor from smelling like a dirty litter box. That would be to seal again the concrete to prevent any residual pet urine odor from working its way back to the surface.

There are a lot of products in the market for coating and resealing. If you are not confident doing it on your own, you can help from an expert. Once the coating is applied, it should effectively block any odors that remain in the concrete.