Last Updated on October 4, 2026 by Umar Farooq
Rinse the garment in cold water from the back, soak it for at least 30 minutes in an enzyme laundry product, wash cold on the longest cycle the machine has, then air dry it and smell it before any heat touches it. Ordinary detergent removes the visible mark on the first wash and leaves the smell behind, which is the entire problem. And whatever else you do, keep chlorine bleach out of it.
That last clause is not a preference about laundry results. It is the one genuinely dangerous thing on this page, so it is dealt with before anything else.
Detergent takes the half you can see
Fresh urine is mostly water, with urea, salts and — in cats specifically — an amino acid called felinine carried along in it. The watery part soaks straight into the fibre and dilutes easily, which is why a cold rinse does more in thirty seconds than a wash cycle will do an hour later. It is also why the visible mark usually disappears in a normal wash, and why people reasonably conclude the job is finished.
What stays behind is the residue left when the water evaporates, plus the bacteria that go to work on it. PetMD, quoting Dr Bruce Kornreich of the Cornell Feline Health Center, describes the sequence plainly: “After a cat pees, the bacteria in the urine decomposes and gives off an ammonia-like odor that’s characteristic of stale, old urine,” and the smell then gets worse because “the urine begins emitting mercaptans, which are the same compounds that give skunk spray its characteristic bad smell” (how to get rid of cat pee smell).
One correction worth making, because the internet is unanimous and slightly off. Nearly every page on this subject names “uric acid crystals” as the culprit, which is the phrase the pet-odour product industry has settled on. The veterinary description is bacterial breakdown of urea and felinine into ammonia and sulphur compounds. The practical answer lands in the same place either way — you need something that digests organic residue rather than something that dissolves soil — but the bacterial version explains the thing people actually notice, which is that the smell returns on a humid day. Moisture restarts the bacteria. Nothing has gone wrong with your washing.
Bleach near urine is a chemistry problem, not a laundry one
Cat urine produces ammonia as it breaks down. Chlorine bleach and ammonia must never meet. Clorox, which makes the bleach, states it with no hedging at all: “Bleach and ammonia should NEVER be mixed since when the two combine, toxic gas is formed that could be fatal” (does bleach contain ammonia). The same page extends the rule to toilet bowl cleaners, rust removers, vinegar and other acids.
The CDC’s chlorine fact sheet gives the household version in one line — “Household chlorine bleach can release chlorine gas if it is mixed with certain other cleaning products” — and then describes what the gas does: “When chlorine gas touches moist tissues (like the eyes, throat, and lungs) it creates an acid that can hurt these tissues” (chlorine).
So the rule for this load is short. No chlorine bleach in the wash. No ammonia-based cleaner on the garment. Under no circumstances both. If bleach has already gone onto a urine-soaked item, leave the room, open a window, and do not go back in to rinse it out. There is a second and much smaller reason to leave ammonia cleaners alone as well: to a cat, ammonia smells like the place they already went, which reads as an invitation rather than a correction.
How to get cat pee out of clothes, in four passes
Think of this as four passes rather than four steps, because the honest version is that you will often run the last three twice. A garment that has already been washed and dried once is harder but not finished — the heat has driven residue into the fibre, so the soak needs longer and the wash needs repeating.
Work from the back of the fabric throughout. Pushing the mess out the way it came in is the whole technique, and it is the step almost nobody does.
- Blot, do not rub. Press with paper towel to lift as much liquid as the fabric will give up. Rubbing widens the wet area and drives residue deeper into the weave.
- Rinse cold, from the reverse side. Hold the back of the stain under a cold tap and let the water push outwards. Warm water starts setting residue here; cold does not.
- Soak 30 minutes or longer in an enzyme product. This is the step that does the work. Enzymes are biological catalysts with one job and no sense of urgency, so give them the full half hour, and overnight for anything already dried.
- Wash cold on the longest cycle available, then air dry. Wash it on its own, and skip fabric softener — it coats fibres and traps exactly what you are trying to flush out.
Then smell the garment while it is still damp, because damp is when the smell is loudest. If anything is left, go back to pass three. The dryer holds no opinion on whether you have finished; it will set whatever remains, warmly and permanently.
Dog urine is the same chemistry on an easier setting
The searches split but the stain does not. How to get dog urine out of clothes has the same answer as the cat version, with one difference that works in your favour: dog urine is more dilute. Cats evolved to conserve water, their urine is concentrated as a result, and that concentration is most of why the pet urine smell from a cat is so much harder to shift than the same accident from a labrador.
Everything above applies unchanged — cold rinse, enzyme soak, cold wash, air dry — and you will usually need one pass instead of two. Accidents on bedding from a house-training puppy clear especially well, because they get caught within minutes, and speed matters more here than any product choice you will make.
Where the textile service and the pet sites part company
The University of Georgia’s textile extension service publishes a urine procedure for apparel that reads very differently from every pet-care page: “Rinse with cool water. Soak in cool water with a heavy-duty liquid detergent. Launder in hot water. If fabric color has been changed, sponge stain with ammonia. Rinse. If stain remains, sponge with white vinegar. Launder” (remove stains from urine).
Two things in there contradict the standard advice, and they deserve separating. The hot wash is defensible, but only as a final pass once the smell has gone, because heat sets anything still present. The ammonia step is one to skip outright. Read it closely and it is not a stain instruction at all — it is colour restoration, for fabric whose dye the urine has already altered. Given what else lives in most laundry cupboards, moving a bottle of ammonia next to a urine-soaked garment is a trade with no upside.
That gives this page its one firm position: cold and enzymatic until your nose clears it, hot only afterwards, ammonia never. The site’s dried blood guide argues the same sequence for the same reason, because these are the same class of stain wearing different labels.
FAQ
Does vinegar actually get cat pee out of clothes?
It helps and it is not sufficient. Vinegar neutralises some of the alkaline residue and covers what is left while it evaporates, which is why a vinegar soak feels like it worked. It does not break the residue down. Use it in the rinse if you like, after the enzyme soak rather than instead of it.
Why does the smell come back after the clothes have dried?
Because moisture restarts the bacteria still sitting in the fibre. If a garment smells clean when dry and smells of urine on a humid day or against warm skin, the residue was never removed — it was only quietened. Re-soak with an enzyme product and wash again.
Can I wash it with the rest of the laundry?
No. Wash it on its own. Urine residue transfers readily to other fabrics sharing the drum, and a load of clean towels that now faintly smells of cat is a far bigger job than the one you started with.
Does the washing machine itself hold the smell?
It can, particularly a front-loader, where residue collects in the door seal and the detergent drawer. If your laundry smells faintly of pet after a cycle that had nothing to do with the cat, the machine is the source — clothes that smell after washing covers how to clear it.
Is hot water ever safe on cat urine?
Only once the smell has gone. Hot water sets residue in exactly the way dryer heat does, so it has no business in the first wash. As a final clean-up pass on a garment that already smells of nothing, it is fine, and the care label is your limit.
Air dry it, then let your nose make the call
The habit that separates a garment saved from a garment binned is checking it damp, before heat, every single time. Enzymes are slow, the first soak is frequently not enough, and a second pass costs you an evening rather than a shirt. The dryer is the point of no return, and it is the only part of this process you cannot undo.
