Now that’s a big question.
The causes behind cat urine stink all have different ways to destroy them. Different materials require different strategies for cleaning.
Getting the stink out of your mattress will require a different approach than getting the stink out your leather shoes.
Even the age of the cat urine spot can make a difference in cleaning it up.
What’s the Stink about Cat Urine?
Cat urine is complicated stuff. And part of keeping your cat (and yourself) happy, is to have a relatively odor free home…but how?
Unfortunately, most of the internet sites on this smelly subject don’t even sniff out even half of the culprits behind the lovely bouquet of cat urine.
It turns out that there are four things in cat urine that contribute to its two odors.
Yes, cat urine has two bad smells, not one. It’s one of the reasons it’s so hard to deal with. Understanding what’s in cat urine makes a difference in getting rid of its stench.
Here’s the Scoop on the Causes of Cat Urine Odors:
The four guilty parties behind the smell are:
- Uric acid
- Sulfur-bearing odorant chemicals
1.) Most of the liquid in cat urine is a solution of water and urea.
- Urea is one of the three main sources of the ammonia smell in cat urine
- When not mixed with water, urea forms odorless solid white crystals.
- Urea dissolves easily in water so it is easy to just rinse it away.
- Water acts upon urea to break it down slowly into carbon dioxide and ammonia.
- Certain enzymes, microbes and fungi can speed up the breakdown of urea.
2.) A minor constituent in cat urine is ammonia itself. (Though the amount is small, a little ammonia stink goes a long way.)
3.) Another minor but smell-causing constituent is uric acid.
- Uric acid is an odorless white crystalline solid.
- Uric acid doesn’t want to dissolve in water, alcohol or much else. It reluctantly dissolves in very hot water. Unlike urea, it is difficult to remove uric acid with water alone.
- Uric acid is stable in acidic environments but it breaks down and releases ammonia in alkaline conditions where pH is greater than 8.
- Enzymes and microbes can help to speed up the breakdown of uric acid in alkaline conditions.
4.) There are small amounts of sulfur-bearing odorant chemicals in cat urine that make a big stink.
- The odorants all contain sulfur which is one of the reasons they stink as they break down. Sulfur compounds are stinky in general.
- These chemicals are pheromones and pheromone precursors. Pheromones are chemicals that encourage different behaviors in animals through smell. Since it’s the job of pheromones to make a stink, destroying their stickiness is not easy.
- Two of these odorants stand out. The amino acid felinine is found in all cat urine.
It breaks down into the pheromone 3-methyl / 3-sulfonyl /1-butanol. It should come as no surprise that biochemists abbreviate this name as “MMB.” When cats spray to mark their territory, the odor they leave behind is from MMB.
- Once excreted, felinine can continue to break down into MMB.
- MMB and related sulfur-bearing odorants are all volatile. So not only do they stink, they keep on stinking until they evaporate away. It takes weeks to months for this to happen. Unless you can get rid of all the MMB and relatives, your cat who is marking will want to renew the odor when it starts to weaken.
- The ways to get rid of these odorants is rinse them away, to wait for them to off-gas into nothingness, or to break them down with using enzymatic cleaning solution for cat urine and microbes. They are resistant to most household cleaners.
How do we get rid of these stinky biochemicals?
We need to clean up both the ammonia-producing biochemicals and the sulfur-bearing odorants.
Here’s the best way to get rid of each of them:
1.) Ammonia is easy.
- Leave it alone and it will evaporate away quickly.
Unfortunately, urea and uric acid both produce more ammonia as they break down and the sulfurous odorants are also long-term stinkers.
- The cheapest and easiest way to get rid of urea is to rinse it away with a lot of water. Remember: urea dissolves in water and water breaks it down. The problem here is that water rinses may not work on uric acid or the sulfurous odorants, depending on where the cat urine spot is located and how old it is.
- Uric acid is best approached with an alkaline cleaner. Hot water mixed with baking soda or borax will have a good chance of breaking down the uric acid though ammonia is produced in the process. This can also take care of the easily-dissolved urea but the sulfurous odorants may survive an alkaline cleaner.
If the cat urine spot is still wet, you can use a lot of cold water to rinse the sulfur-bearing odorants away along with the urea and uric acid. The approach is very similar to cleaning up blood spots.
Alternatively, you can also use an enzymatic cleaner specifically formulated for cat urine which attack everything in it that stinks.
There are some things you don’t want to do if you want to get rid of your stink:
This should be obvious, but we’ll say it anyway:
You don’t want to use an ammonia-based cleaner to clean up cat urine which already has ammonia in it. Ammonia has no effect on itself.
- Avoid an acidic cleaner like vinegar or hydrogen peroxide. You may see some temporary improvement from the oxidizing action of these solutions, but uric acid and the sulfur-bearing odorants will resist them.In fact, uric acid is stable in acidic conditions so once the acidic cleaning solution dries up, the uric acid crystals can go back to breaking down slowly and releasing more ammonia.
- Don’t use a chlorine bleach. Mixing chlorine bleach with the ammonia in the cat urine will make hydrochloric acid and toxic chloramine gas.If you thought the ammonia stench of cat urine was bad, chloramine vapor is worse.It’s nasty, poisonous, and corrosive. Even though the amounts produced are small, you might even make yourself sick and could poison your cat. It’s best to skip the bleach.
The chlorinated solvents used in dry cleaning do not work on the sulfurous odorants. In fact, they break felinine down into stinkier stuff like MMB and make your clothing smell worse.
Best enzyme cleaner for cat urine:
If you use an enzymatic cleaner, don’t use one of the do-it-yourself recipes from the internet, one of the general formulations for pet stains or one formulated for dogs.
Those won’t have the enzymes and microbes targeted at breaking down sulfurous odorants like felinine and MMB which are found only in cat urine.
Get a formulation specifically for cat urine online or at a pet store.
You can get this formulation from Natures Miracle Urine Enzymatic Cleaner from Amazon.
When using an enzymatic cleaner, don’t just apply it and let it dry.
These cleaners have enzymes and living microbes that target urea, uric acid and the sulfurous odorants; and they work best when damp.
These enzymes and microbes also destroy the stinky stuff in cat urine through biological breakdown, which takes more time than the chemical detergents you use to clean your home – so give your enzymatic cleaner enough time to work.
How to Get Rid of Cat Urine Smell from Almost Everything
While the chemistry of cat urine is important, the physical setting of where your cat decided to go also matters.
When it comes to cleaning strategy, we can split cat urine targets into things you can safely soak, things you shouldn’t or can’t soak, and – we have to be honest here – things you can’t clean.
Cleaning Things You Can Safely Soak
Anything you can safely send through the washing machine or soak in a bucket is a candidate for the rinsing technique.
The object of this method is to physically rinse away all the cat urine biochemicals and send them down the drain with the rinse water.
This works best while the urine spot is still wet, while the urea and sulfurous odorants are still in the solution.
Once the urine has dried, the sulfurous odorants and the microscopic crystals of urea and uric acid are harder to remove.
The first step is to place the item in a washing machine, bucket, bathtub or barrel, and then rinse it out with lots of cold running water.
- In a washing machine, just set the water temperature to cold and don’t add anything like detergent.
- Run the washing machine at least twice.
- For a bucket or barrel, use a hose and in the tub, just run the water for at least a half hour.
You can use this approach on clothing, curtains, pillows, anything that you can safely soak.
This is not a safe method for dry-clean-only fabrics. (Use the method recommended for items that can’t be soaked, which we describe in just a bit.)
The second step is for any items that still have some smell after they have dried. Some odor often lingers in items where the urine spot had a chance to dry before rinsing with water.
- For things that can go into a washing machine, wash them in cold water and borax.
- Use pure borax and not a borax detergent which can have other additives.
- After the borax treatment, all the uric acid should be gone. Any smell left will be from the sulfurous odorants, which can be removed by blotting with an enzymatic cleaner.
Enzymatic cleaners for cat urine work best if they stay damp and are given time to work – so blot the item you’re cleaning and put it in an airtight bag overnight.
You might be wondering:
Why not just use an enzymatic cleaner instead of going through the trouble of rinsing with water followed by washing with borax?
After all, the enzymatic cleaners that are formulated just for cat urine target the sulfurous odorants plus urea and uric acid.
Our answer is simple:
Enzymatic cleaners are not cheap.
Unless you live in a water-challenged area like West Australia or the Mojave Desert, the water-rinse approach is effective and saves money.
That why we recommend you try it first for items that can be safely soaked.
Cleaning Things You Shouldn’t or Can’t Soak
Frankly, for your carpet, your wool brocade couch or your silk prom gown, go straight for an enzymatic cleaner formulated for cat urine.
As we already pointed out, acidic cleaners like hydrogen peroxide and vinegar solutions don’t work on uric acid and the sulfurous odorants.
Using an alkaline cleaning solution may get uric acid out, though it temporarily reek of ammonia while it works; but it won’t touch the sulfurous odorants like MMB and felinine.
Remember, any residual felinine will continue to slowly break down into more stinky MMB. Only time or an enzymatic cleaner can make the stink of cat urine go away permanently.
Here’s how to clean with an enzymatic cleaner:
Containing the urine spot is important.
- First blot up any excess urine. Remove as much as possible with cleaning rags or paper towels.
- Because containment is key, don’t use water to blot or rinse the area of the urine spot, especially on upholstery or carpets. Water will only spread the urine deeper into the item to be cleaned, making it more difficult for the enzymatic cleaner to reach it.
- Test the enzymatic cleaner first in an out-of-the-way spot to determine whether the cleaner will stain the item or leach color out of it. If the enzymatic cleaner does stain or bleed color, you have two options:
- You can put the item aside for one to five years, to allow the cat urine smell to vanish with time.
- If you can’t wait, you may want to try an industrial cleaning method.
- Blot the urine spot with the cleaner. Then cover the cleaner-dampened spot with something that will prevent or slow down drying since the enzymes and microbes in the cleaner work best when wet.
- Wait. Enzymatic cleaners take time.
- Be prepared to repeat the treatment, especially for dry urine spots, large spots, old spots and spots made by un-neutered male cats. You may need to use the cleaner two or three times to get the smell out.
- This is important: Especially for wood floors, carpets, walls and upholstery: keep your cat away from the area you are cleaning until you are done. He or she may feel obliged to undo all your hard work if any smell still remains.
Special Cleaning Cases
Carpet and Upholstery
While a lot of cat urine spots can be fixed with an enzymatic cleaner, a larger or persistent spot may require the use of an industrial-grade rug-and-upholstery cleaner.
Don’t use one of those cheap rug-cleaning knock-offs sold to the public at department and discount stores. They don’t have the heft to do the job.
Rent one of the machines that professional cleaners use. (HomeDepot rents out industrial carpet cleaners)
An industrial rug-and-upholstery cleaner works by injecting a cleaning solution into its target and then removing the spent solution through a powerful suction.
The item that was cleaned is always left a bit damp afterward and will take a few hours to dry.
These machines work on carpets, rugs, couches and other upholstered seating.
Some cleaning machines will also work on heavy curtains and fire-safety drapes.
The good news is that there are enzymatic cleaning solutions now made for these cleaners.
The injection and removal of the cleaning solution removes the urea and uric acid.
Enzymes left behind in the damp item after the machine has made its cleaning pass attack any sulfurous odorants left behind.
This is a highly effective cleaning method for getting rid of cat urine odor…
It has one big downside:
Renting (or buying) an industrial-grade rug-and-upholstery cleaner is not cheap.
Try blotting your cat urine spot with an enzymatic cleaner first – it may save you the expense of renting an expensive industrial cleaning machine.
Getting Rid Of Cat Odor In A House
You may be faced with some carpet with has been repeatedly used by one or more cats as a potty spot.
For example, you might be cleaning such a carpet in a rental apartment or house that had cat-loving but less-than-clean tenants and the whole house smells like cat urine.
We won’t lie about this:
Sometimes, even an industrial-grade rug cleaner might not get all of the odor out because it may have soaked into the wood or cement floor underneath.
The only thing to do in such a case is replace the carpet and its padding, clean the floor underneath, and in extreme cases, seal the flooring.
Shredded Newspaper For Cat Litter
Cat urine on paper is tricky because it absorbs liquids so well. After all, shredded newspaper has been used often as an emergency or poor-man’s kitty litter.
Another problem with cat urine on paper is that solutions of urea can attack the cellulose in paper under alkaline conditions. It’s important to dry the paper right away. If it’s already dry, do not re-wet it.
- If the paper is still wet, blot up the excess fluid immediately. Then let the paper dry completely.
- Once the paper is dry, take a soft brush and brush the surface of the paper to remove any crystalline residue of urea and uric acid. You might not see it, but there are probably some microscopic crystals in and on the paper. Removing them will lessen the ammonia smell.
Now you have a decision to make:
- If the paper is something you don’t use everyday, you can put it aside where it can air out. In one to five years, all the cat stink will go away by itself.
- If you need to use the paper, book conservators recommend using an enzymatic cleaner. Soak a sponge in the cleaner and then wring it out so it is damp. Then brush the paper or book page with the sponge. You want to dampen, not soak the paper. This process may need to be repeated several times to get all of the smell out. If you need the paper or book to be flat, wait until the paper is just barely damp and then press it under something heavy, like a pile of books.
Remove Cat Urine From Leather
There are several ways to approach cat urine spots on leather.
First, be aware that the glycol-based and solvent-based leather cleaners will not remove sulfurous odorants and some won’t remove uric acid.
Be aware that some enzymatic cleaners should not be used on leather. Most enzymatic cleaners that will hurt leather usually say so on the label – so read the label before you buy!
Some small leather items can be cleaned using the rinsing method, especially if they are made of vegetable-tanned and latigo leather:
- This method can work for items like belts, unlined purses, wallets and shoes with the warning that water can harm leather – so you need to counteract the water damage when you’re done.
- Don’t put leather items in the washing machine – use a bathtub or sink.
- Dry all metal hardware like rivets, clasps and buckles immediately after removal from the water. Leaving them wet or even damp will corrode them and hurt the leather.
- For grained leather, apply a leather restorative like neatsfoot oil or Lexol while it’s still damp to keep the leather from getting brittle and shrinking.
- Don’t soak napped leathers like suede or deerskin. Put a towel under the leather and blot the urine spot with water instead, just like you would water blot a blood spot on a delicate fabric. Use a suede brush instead once the leather has dried.
- Blot with a borax solution or enzymatic cleaner if any smell remains after the leather has dried. Don’t forget to do a stain test first.
- Always use a leather restorative on grained leathers after each round of blotting.
For large leather items like car seats and couches:
- Clean these with the blotting method using borax solutions followed by enzymatic cleaners that are safe for leather.
- After every round of blotting, use a saddle soap or other leather soap matched to the color of your upholstery, to help restore the color and condition of the leather.
- Never use a rug-and-upholstery cleaning machine on leather upholstery
Porous Surfaces like Wood, Concrete and Plaster
Cleaning cat urine from concrete floor and the porous surfaces of walls/floors with enzymatic cleaners.
You can soak vinyl wallpaper, bare and painted wood, grout, and cement with enzymes; but wall paint, drywall and plaster should be blotted.
Unless it’s vinyl, wallpaper should be treated like paper.
If several rounds of blotting or soaking don’t work on these porous floor and wall materials, there may be uric acid and sulfurous odorants so deep in the pores that only time will remove them.
- If a surface is painted, remove the old paint and apply new paint.
- Un-cleanable wood should be sanded and sealed, then painted or varnished.
- Uncleanable tile grout should be replaced.
- Uncleanable cement should be sealed and then painted.
So, if your whole house smells like cat urine, it’s safe to say we covered it here to eliminate it!
Cat Veteran has done a lot of research, asked a lot of questions and drawn on a lot of first-hand experience to gather this information for you.
Not only have we tried to advise you on how we would approach our own cat urine cleaning problems, we have given you the chemistry behind cat urine and what works to remove the biochemicals behind the stink.
As always, we welcome your feedback on this and any other of our articles on cat care.