Quick answer: If the litter box still smells of ammonia despite regular cleaning, the most common causes are: ammonia continues to form in the hours after the cat uses the litter box (not just during urination), the plastic tray itself retains odor in its micro-scratches over time, and a too-thin layer of litter (less than 7 cm) allows urine to reach the bottom of the tray without being absorbed.
You clean the litter box regularly, you change the litter as recommended, and yet the ammonia smell always returns. This is not a hygiene problem on your part — it's a chemical problem that cleaning alone won't solve.
Ammonia forms afterwards, not during
When your cat urinates, fresh urine has almost no smell. The ammonia smell appears when bacteria in the litter decompose the urea contained in the urine. This process begins a few hours after the cat uses the litter box — even if the litter has perfectly clumped the liquid. Therefore, removing solid waste is not enough to stop the production of ammonia gas that escapes into the ambient air.
The tray itself can retain odor
Plastic trays gradually absorb odor molecules in the micro-scratches that form over time and with the use of the scoop. Even after a thorough cleaning with soap and water, these scratches can continue to release a residual odor. If your tray is more than a year old and the odor persists even when clean, replacing the tray often makes more of a difference than additional cleaning. Also be careful with the product used for cleaning: bleach can paradoxically worsen the odor problem.
A too-thin layer of litter
An insufficient layer of litter allows urine to reach the bottom of the tray, where it spreads and partially dries on the plastic without being properly absorbed. These residues continue to release ammonia long after visible waste removal. A thickness of 7 to 10 cm is generally recommended depending on the type of litter.
Fragrances mask, they don't solve anything
Many litters and commercial products rely on synthetic fragrances to mask the odor. The problem: ammonia continues to be produced, and the mixture of artificial fragrance and ammonia often creates a more complex and more present odor, not fresher. The cat's nose, much more sensitive than ours, perceives this mixture even more strongly. Even the famous baking soda, often recommended as a natural remedy, does not actually act on ammonia due to basic chemistry reasons.
In a multi-cat household, the problem intensifies
If you have multiple cats, these causes are often compounded by an additional factor: an insufficient number of litter boxes for the number of cats. Each overused litter box accumulates ammonia faster, in addition to creating stress for the cats concerned.
What really works
To permanently limit ammonia odor, three levers are more important than cleaning alone:
- Twice-daily scooping of solid waste to limit bacterial proliferation.
- A sufficient layer of litter (7 to 10 cm) for complete absorption.
- A treatment that acts on the ammonia molecule itself, rather than a fragrance that merely covers it.
This is the latter approach that CatDeo™ follows: a technology that chemically breaks down ammonia at the source, without added fragrance, for a litter that truly no longer smells — not just masked for a few hours.