How to Get Urine Out of a Mattress: Fresh Accidents, Old Stains & the Smell

It happens in every home sooner or later. A child wets the bed at 3 AM. A new puppy sneaks onto the guest bed. An older parent has an accident. A cat decides your mattress is the new litter box. However it happened, you now have a wet spot, a smell, and a mattress that cost real money.

The good news: most urine accidents can be cleaned well if you act fast and use the right method. The bad news: the most common home tricks — soaking the spot, scrubbing hard, or covering the smell with spray — often push the urine deeper and make the odor come back. Here is how our mattress technicians handle urine every week in New York City and Long Island homes, and what you can safely do yourself tonight.

Why urine is harder to clean from a mattress than from a floor

A mattress is basically a big sponge. Urine goes through the cover, into the quilting, and down into the foam or fiber layers below. You cannot rinse it out the way you would rinse a shirt, because there is nowhere for the water to drain.

Urine also changes as it dries. The water evaporates, but salts and uric acid crystals stay behind deep in the padding. Those crystals hold on to odor. Every time the room gets humid — a hot July night, a steamy shower next door, a wet NYC spring — they absorb moisture and release the smell again. That is why a mattress can seem fine for weeks and then suddenly smell like urine.

So the goal is not just to make the top look clean. The goal is to break down what soaked in, pull out as much liquid as possible, and dry the mattress fast.

Step by step: how to clean a fresh urine accident

If the spot is still wet, you are in the best position. Work in this order:

1. Strip the bed right away. Pull off sheets, the mattress pad and any protector, and put them straight in the washer. Check the box spring or bed base too.
2. Blot — do not rub. Press thick, dry towels or paper towels firmly onto the spot. Stand on a folded towel or kneel on it to push the weight down. Change towels until they come up almost dry. Rubbing spreads the urine sideways and makes the stain bigger.
3. Apply an enzyme cleaner. Use a cleaner made for urine (often sold as a pet stain and odor product). Enzymes break down the parts of urine that cause the smell. Spray enough to reach as deep as the urine went, but do not flood the mattress. Follow the label and let it sit for the time it says.
4. Blot again. After the dwell time, blot out as much moisture as you can with clean towels.
5. Cover with baking soda. Once the area is just damp, sprinkle a thick layer of baking soda over it. It helps absorb leftover moisture and odor. Leave it for several hours or overnight, then vacuum it up with an upholstery attachment.
6. Dry it fast. Point a fan at the spot, open a window or run a dehumidifier. Stand the mattress on its side if you can, so air reaches both sides. Do not put the sheets back until the spot is fully dry to the touch.

Always test any cleaner first on a hidden spot near the edge of the mattress, and check the manufacturer's care tag. Some mattress warranties are voided by stains or by soaking, so it is worth a quick look.

What about the hydrogen peroxide trick?

Many people mix 3% hydrogen peroxide, a little baking soda and a drop of clear dish soap, then spray it on old urine stains. It can lighten yellow marks on a white cover. But peroxide is a mild bleach. It can lighten colored or patterned covers, so test first, use it only on white fabric, and never let it soak deep into foam. Mix only what you need and do not store it in a closed bottle.

How to clean old, dried urine stains

A dried stain usually shows up as a yellow ring with a darker edge. That ring is where the urine dried from the outside in and left minerals at the border. Old stains are harder, but not hopeless:

• Lightly re-wet the area with an enzyme cleaner so the enzymes can reach the dried crystals. A light mist several times works better than one heavy pour.
• Give it time. Enzymes work slowly. Cover the damp area loosely with plastic wrap for the dwell time on the label so it does not dry out too early.
• Blot, add baking soda, vacuum and dry just like a fresh accident.
• Repeat if the smell is still there. Old or repeated accidents often need two or three rounds — or a professional extraction that can flush the area and pull the liquid back out.

The yellow color sometimes stays even after the smell is gone. That is a dye change in the fabric, not leftover urine. A clean, odor-free mattress with a faint mark is a good result.

Every mattress type is a little different

Mistakes that make urine smell worse

• Pouring water on it. Extra water carries the urine deeper and wider, where you cannot reach it.
• Using bleach or ammonia cleaners. Bleach can damage the cover and foam. Ammonia smells like urine to pets, so it can invite them back to the same spot. Never mix bleach with ammonia or vinegar — the fumes are dangerous.
• Using heat. A hair dryer, iron or steam can set the stain and bake the odor in. Use moving air, not hot air.
• Covering it with fragrance. Scented sprays hide the smell for a day. When the scent fades, the urine smell is still there.
• Making the bed too soon. A damp mattress under sheets stays damp, and damp padding can start to smell musty on top of the urine smell.

Kids, pets and repeat accidents

Bedwetting

Bedwetting is common, and nobody should feel embarrassed about it. The best thing you can buy is a good waterproof mattress protector that is breathable and quiet. Keep two, so one can be in the wash while the other is on the bed. For a child's room, use kid- and pet-safe cleaners, and let the mattress dry fully before bedtime.

Dogs and cats

Pets go back to places that smell like urine to them — even when you can't smell anything. That is why a full enzyme treatment matters. Cat urine is especially strong and is a common reason people call us. If a pet is suddenly having accidents on the bed, it is worth asking your vet, since it can be a sign of stress or a health issue. If the accident also reached the carpet or rug, our guide on getting pet urine smell out of carpet walks through it.

Other accidents

Many of the same rules work for other messes in the bedroom. For a stomach bug, see how to get vomit out of carpet and mattresses.

When to call a professional

Home cleaning works well for a small, fresh accident. Call a pro when the smell keeps coming back, the stain is large or old, there have been several accidents in the same spot, it is cat urine, or the mattress is memory foam that you do not want to soak.

When our IICRC-certified technicians do mattress cleaning for urine, we:

• Find the full spot, including the parts that soaked in and spread under the surface.
• Treat it with professional enzyme products from our pet stain and odor removal service — organic and safe for kids and pets.
• Flush and extract with a controlled amount of solution, so the urine is pulled out instead of pushed deeper.
• Clean the whole surface evenly to avoid new rings, then set up airflow so the mattress is usually dry within a few hours.

A urine cleaning is also a good time to do a full deep clean of the mattress. Our article on mattress cleaning, dust mites and allergies explains what else builds up inside a mattress over time.

We clean mattresses in apartments all over Manhattan (with a certificate of insurance for your building when needed), in homes across Brooklyn and Queens — including Forest Hills — and throughout Nassau County and Suffolk, including the Hamptons.

Frequently asked questions