People usually land here after one of two moments: you’ve just found a fresh patch of cat wee and you want the smell gone fast, or you’ve cleaned it already and the odour keeps drifting back—especially on warm, humid days. If you miss the urine that’s soaked in, the scent can linger and some cats will return to the same spot, guided by what they can still smell.
Cat urine odour is stubborn because the chemistry is stubborn. The aim is to remove the residue, not mask it. The steps below move from immediate clean-up to deep treatment for carpets and floors, and then into prevention—because repeated accidents often have a medical or litter-tray reason worth catching early.1, 3
Why cat urine smells so strong
As urine dries, urea breaks down and releases ammonia-like odours, and cat urine can be especially pungent because of its species-specific compounds. One of these is felinine, a sulphur-containing amino acid found in domestic cat urine, which contributes to that distinctive “cat wee” character—particularly in entire (undesexed) males, who excrete much higher amounts than females or desexed males.5, 6
Smell isn’t just the wet patch. It’s what gets left behind inside fibres, underlay, timber joins, grout lines and subfloor. Once it’s there, heat and humidity can lift it back into the room again.
First response: what to do straight away
1) Blot—don’t rub
If it’s fresh, press paper towel or a clean cloth firmly onto the spot to draw out as much liquid as you can. Replace with dry towels and repeat until they stop coming up damp. Rubbing just pushes urine deeper into fibres.
2) Rinse lightly with cold water, then blot again
A small amount of cold water helps dilute what’s left, making it easier to lift out. Blot thoroughly. Avoid hot water at this stage—it can make odours harder to shift in fabrics.
3) Skip ammonia-based cleaners
Do not use ammonia-based products. Cat urine already contains ammonia compounds, and adding more can make the area smell “urine-like” to a cat, increasing the chance they’ll revisit the spot.2, 3
4) Don’t disinfect urine with bleach
Bleach and urine is a risky combination. Urine can contain ammonia, and mixing bleach with ammonia produces toxic gases (chloramines). Keep bleach out of the cat-wee toolkit, especially in enclosed laundry rooms and bathrooms.4
Cleaning solutions: what works (and what doesn’t)
Enzymatic cleaners: best for odour removal
If you want the smell gone rather than disguised, an enzymatic pet-urine cleaner is usually the most reliable option. These cleaners are designed to break down the urine residue that keeps producing odour. They’re also useful because they reduce the scent cues that can draw a cat back to the same patch.3
- Soak the area to the depth the urine reached (this matters more than scrubbing).
- Leave it for the full contact time on the label.
- Blot, then allow to air dry completely.
If you can still smell it once dry, repeat. Old deposits often need more than one pass.
Vinegar and bicarb: useful, but limited
Vinegar (diluted) can help with light, fresh odours on some surfaces, and bicarb soda can absorb smells while it sits. The problem is that “DIY” methods often can’t reach urine that has travelled under carpet backing, into underlay, or into timber joins—so they can look successful at first, then fail later when conditions change.3
If you do use bicarb on carpet, vacuum only once it’s fully dry. Damp powder can gum up vacuums and hold odour in place.
Deep cleaning by surface
Carpet and rugs
- Find the full area: the visible stain is often smaller than the soaked patch. If you have a UV light, it can help locate older urine.
- Soak, don’t just spray: apply enzymatic cleaner generously so it reaches the underlay if needed.
- Weight and wick: after treatment, place clean towels over the spot and weigh them down for an hour to draw residue up.
Be cautious with steam cleaning: heat and moisture can drive odour deeper or “set” it if urine residue remains. If you steam-clean, pre-treat properly with an enzymatic cleaner first and let it do its work before any hot extraction.
Upholstery and mattresses
Test cleaners on an inconspicuous section first. Use minimal water—soft furnishings hold moisture for a long time, and a damp core can sour. Enzymatic cleaner is still the main tool, but drying is the real finish line: airflow, fans, and time.
Hardwood floors
Timber is unforgiving because urine can slip between boards and into the subfloor. Wipe immediately, then treat with an enzymatic cleaner that’s labelled safe for sealed timber (follow the product directions closely). Avoid flooding the area. If the smell persists, it may be under the boards, and replacement or sealing may be the only permanent fix.
Tiles and grout
Tile itself is easy; grout is not. Clean the surface, then work an enzymatic cleaner into grout lines and let it sit for the full contact time. Rinse and dry well. Repeat if needed.
When the smell keeps coming back
A returning odour usually means one of three things:
- Depth mismatch: the cleaner didn’t reach where the urine travelled (underlay, subfloor, foam padding).
- Not enough dwell time: enzymatic products need time to break down residue.
- Repeat urination: the cat has re-soiled the area, sometimes quietly and in the same spot.
Prevention: reduce repeat accidents at the source
Keep litter trays genuinely usable
Cats can avoid a tray that’s dirty, hard to access, in a noisy spot, or simply not to their preference. In multi-cat homes, competition and tension can also push a cat to toilet elsewhere. A common rule of thumb is one tray per cat plus one extra, placed in different locations, and kept very clean.1
Take house-soiling seriously as a health signal
Urinating outside the tray can be caused by medical problems (including urinary tract disease) as well as stress or anxiety. The practical first step is a vet check to rule out pain, infection, inflammation, bladder stones, kidney disease, diabetes and other conditions that change urination patterns.1, 7
If your cat is straining to urinate, producing little to no urine, or crying out, treat it as an emergency—urinary blockage can be rapidly life-threatening, especially in male cats.1
When to call a professional cleaner
Professional help is worth considering when:
- the urine has soaked into underlay, subfloor or wall edges
- the smell returns after drying, despite repeat enzymatic treatments
- you’re dealing with large areas, multiple incidents, or rental/real-estate inspection pressure
Ask what process they use for pet urine specifically (not just general carpet cleaning), and whether they can treat underlay and subfloor if needed.
Final thoughts
Cat wee smell isn’t a willpower problem. It’s chemistry, depth, and timing. Blot quickly, use an enzymatic cleaner properly, and dry thoroughly. Then look upstream: a clean, well-placed litter tray and a prompt vet check for any cat that starts toileting outside the box will prevent far more odour than any spray ever will.1, 3
References
- RSPCA Australia Knowledgebase — Why is my cat urinating inappropriately? (updated 30 May 2024)
- RSPCA NSW — Cats: trouble toileting (includes advice to avoid ammonia when cleaning soiled areas)
- VCA Animal Hospitals — Inappropriate elimination disorders in cats (includes enzymatic cleaner guidance and litter box factors)
- Healthline — Never mix bleach and ammonia (chloramine gas risk; urine contains ammonia)
- Hendriks WH et al. Felinine: a urinary amino acid of Felidae. (Review) PubMed
- Miyazaki M et al. A major urinary protein of the domestic cat regulates the production of felinine. PubMed
- VCA Animal Hospitals — Inappropriate elimination disorders in cats (medical and behavioural causes overview)
- Merck Veterinary Manual — Urinalysis (notes on species differences in urine odour and ammonia)
Veterinary Advisor, Veterinarian London Area, United Kingdom