How To Remove Pet Urine From Concrete Garages And Basements

No matter how good your pet is, sometimes they have accidents. That moment when you open the garage or basement door and the stench of urine hits your nose is enough to give anyone a bad day. 

Because concrete is porous, the smell of pet urine tends to be challenging to get rid of. 

We had some puppy pads in the garage during a recent hurricane for her to use. Let’s just say that her aim wasn’t that good. 

Unfortunately, I needed to figure out how to remove pet urine from concrete garages and basements. 

Removing the smell of pet urine from concrete floors can be difficult. You can use a UV light to locate set-in stains, then use trisodium phosphorate to pre-treat the stain. Finally, you can use urine enzymatic cleaner to neutralize and remove the bacteria and seal the concrete floors.

After a few failed attempts, I finally found something that worked. In this article, we will look at why pet urine is so hard to remove, how to remove the stains, and how to protect your concrete floors so the next accident is easier to clean.


Why Is Urine So Hard To Remove From Concrete?

Many people think that because concrete is hard, spills won’t stain, but it’s the opposite. 

Unsealed concrete is porous and acts like a sponge absorbing any liquid left on its surface. So even polished concrete will absorb any liquid that is spilled on it.

When the urine on a concrete floor dries, the concrete bonds with the uric acid crystals in the urine, which then absorbs them deep into the pores of the concrete. 

Most people smell urine and clean the entire floor with a regular cleaner, but the smell keeps coming back. 

Two things are happening to cause the scent to linger. 

  • The uric acid embedded in the pores of the concrete doesn’t bind with ordinary soap products,
  • Uric acid forms crystals over time. So, when you wash the floor, you introduce a liquid to the crystals, and all the smelly bacteria are released in the form of gas, bringing the smell back.  
Urine stain on concrete

How To Find Dried Urine Stains

Finding urine stains can be challenging. 

You may have discovered the smell long after the pet urinated on the concrete floor. Or, if the urine is already dry, it becomes harder to detect until it gets wet. 

You may even have already cleaned one or two spots previously, hiding the actual source of the scent. 

Luckily there is one surefire way to detect the source of the smell: a UV light (a black light). 

The wavelength in UV lights reacts to the phosphorus and proteins in the urine, making them glow. They also make UV flashlights which are less expensive and work well in a dark room.

Start by getting your garage or basement as dark as possible. Turn off or block any light source and close all doors.

Scan the concrete floor with a UV flashlight in sections, holding the flashlight no more than three feet off the concrete floor. Look on the garage or basement walls, as some pets (usually males) will lift a leg and urinate on the walls.

If you have drywalled your garage or basement, you’ll need to remove any affected sections and replace them. Drywall is extremely porous, and you won’t be able to remove the urine smell. 

Fresh or old urine stains appear as blue, green, or yellow markings. 

Once you find a urine stain, use a concrete marker to mark it so you know what areas you need clean. You can also use chalk (just don’t get it wet). Some people draw four arrows pointing to the stain.


How to Use Trisodium Phosphate (TSP) to Remove Urine on Concrete

Now that you know precisely where any fresh or old urine stains are, you must clean the areas with a specialized cleaner. Trisodium phosphate, or TSP, is one of the most effective heavy-duty cleaners to help you get urine smells out of concrete floors. 

TSP works by eliminating the bacteria of the bacteria in the urine, the stains, and other residue left by the urine. The only thing the TSP leaves behind is the uric acid crystals. 

We’ll tackle those in the next section with enzymatic cleaners. 

If the pet urine stain is fresh and not set in, you only need to use TSP to clean the accident. 

This is because fresh urine has not had time to form uric acid crystals, so you won’t need an enzymatic cleaner to remove the smell. The TSP will be able to do that.

Here is a guide on how to use TSP on new urine stains.

What You Will Need

  • A stiff bristle brush
  • TSP (Trisodium Phosphate)
  • Gloves
  • Dust mask
  • Goggles
  • Hot water
  • Wet/Dry Vacuum

Step 1-Prepare The Area

Before you mix the TSP, you need to prepare the area. 

As soon as you spot the urine, you need to soak up the excess urine with a paper towel. Remember to dab the urine up, not smear it, or the stain will get bigger. 

Then, throw the paper towel away in an outside trash can so the smell doesn’t get into another part of your home.

Step 2-Mix The TSP And Scrub The Spot

Next, you must make the TSP solution by mixing ½ cup of TSP with 1 gallon of hot water. 

Pour half of the mixture onto the urine spot, then use a scrub brush to scrub the area. Work in small 3 x 3 ft sections.

After scrubbing, let the mixture sit on the urine for at least 10 minutes. The goal is to let the solution dry slowly. The longer the concrete stays wet, the better it will soak up the TSP solution. 

Keep applying the TSP solution as the mixture starts to dry. 

The urine smell will get stronger. That’s a normal reaction as the TSP reacts with the uric acid, bringing the urine residue to the floor’s surface. 

Step 3-Rinse The Area

Once the TSP solution absorbs into the concrete floor, rinse that area with clean hot water. The hot water will remove the TSP and any urine residue.

Step 4- Vacuum The Area

Once you have rinsed the area, you need to keep the water from spreading the lifted urine residue to the rest of the floor. 

Use a wet and dry vacuum to vacuum the TSP solution and hot water. 

Step 5-Repeat If Needed

You can repeat steps one to four once more if the smell remains, but it should be gone. Next, leave the concrete to dry for a full 24 hours. 

When the area is dry, the urine smell should be gone. 

However, you may discover that the concrete floor is whiter in the areas due to the acids in the urine stain. 


How to Use Urine Enzymatic Cleaners on Concrete

Urine enzymatic cleaners work well for older urine stains that have already dried and absorbed into the concrete floor. 

Enzymatic cleaners use good bacteria to digest foul smells, stains, and waste. The bacteria create enzymes to break the uric acid crystals into smaller pieces. 

It helps the bacteria digest the smaller pieces and break them down into carbon dioxide and water, effectively removing any lingering urine smell. Most people use treatment before using a urine enzymatic cleaner to ensure no urine smell is left.

To eliminate old or dry urine stains, start by following the steps mentioned in the trisodium phosphate (TSP) section to prepare the concrete before using the urine enzymatic cleaner. 

This two-step system works to eliminate all traces of the urine smell. 

This is how you use urine enzymatic cleaners.

What You Will Need

  • Enzymatic cleaner
  • Gloves
  • Scrub brush
  • Clean deck or household sprayer
  • Tarp

Step 1-Prepare The Enzymatic Cleaner

First, prepare the enzymatic cleaner solution by following the instructions on the container. If you have a large area that you need to treat, buy the larger containers of the cleaner as you might run out before you are done if you use a small bottle.

Before you begin, ensure the floor is dry from the TSP pre-treatment the day before. 

Step 2-Apply The Treatment

Apply the enzymatic cleaner treatment to the affected areas and work in 3 x 3 sections. Using the scrub brush, work the solution into the urine stains you found using the UV light. 

Be sure to saturate the floor, adding more of the enzymatic cleaner treatment, so it stays wet.

For easier application, use a clean spray bottle. Be sure it has not been used for anything else, as any residue from old cleaners or other liquids can lower the effectiveness of the treatment. 

Areas affected most by the pet urine will bubble. You may need to treat those areas again if the smell persists. 

Step 3-Let It Sit

Keep the area wet for at least 10-15 minutes so the treatment can soak into all the layers of the concrete. Then let it dry overnight (don’t wash it off). 

You can put a tarp over the treated areas for the best results to slow the evaporation. This helps keep the area wet and lets the treatment work for longer.

Step 4-Repeat If Needed

After the treatment has dried completely, remove the tarp and air out the garage or basement. 

If any areas still have a lingering urine smell, repeat steps 1-3 until the scent is gone.


Seal Your Concrete Floor to Help Prevent Future Urine Stains

Sealing your concrete garage or basement floor is important because it closes the pores in the concrete. Sealants create a protective barrier between the concrete floor and spills or accidents. 

So when there is another accident, it is easy to clean. The urine won’t stain the concrete, and the smell should be gone after you clean the accident. 

This is an excellent way to keep other pets from urinating and ‘marking’ it as their spot. 

Sealing the concrete also protects it from the harsh chemicals you usually need to use to remove stubborn urine stains. Prevention is the best way to keep your pets from urinating on the concrete basement or garage floor.


Summary

The urine smell can linger if you have a fresh or old pet urine stain on your garage or basement concrete floor. 

Treat fresh pet accidents with a Trisodium phosphate (TSP) solution. For older, set-in stains, use a two-step system that includes pre-treating with TSP and an enzymatic cleaner as the primary treatment.  

This should permanently eliminate the urine stain from your concrete garage or basement floor.