How to Keep Litter Box From Smelling: 9 Fixes That Work

Quick answer: How to keep litter box from smelling comes down to removing waste before it builds up. Scoop at least once a day, wash the box weekly with warm water and unscented soap or baking soda, and keep one more box than you have cats. Skip scented litter and covers, which hide odor from you but not from your cat.

Here’s the part people get backward. Most odor products are built to cover the smell, while vets and shelters tell you to remove it. When I read the ASPCA and Cornell guidance side by side, not one of their fixes is a fragrance.

Your cat’s nose is far better than yours. A box that smells “fine” to you can still put a cat off, and that’s how a smell problem turns into a peeing-on-the-rug problem.

Why Your Litter Box Smells

These are the usual culprits. Most homes have more than one.

1. Waste sits too long. Urine clumps and feces left for days are the main source.
2. The litter is never fully replaced. Scooping removes clumps, but old litter and residue stay behind.
3. Too few boxes for the number of cats. Each box gets used more, and dirties faster.
4. The box itself is old. Cornell says to replace boxes that smell or are cracked.
5. Not enough clumping litter. Too thin a layer lets urine reach the bottom and pool.
6. Masking instead of cleaning. Perfume doesn’t remove waste, and the ASPCA warns that scented products can turn a cat off the box.
7. Accidents outside the box. A hidden spot on carpet keeps the room smelling like a litter box.
8. More urine than usual. Some medical problems make cats pee more, which means more wet litter.

How to Keep Litter Box From Smelling: 9 Fixes

1. Scoop at Least Once a Day

The ASPCA says to scoop at least once a day, and the Cornell Feline Health Center says to remove feces and clumps daily with clumping litter. Then top up with fresh litter.

In practice, I’d scoop twice a day when you’re home, since the ASPCA calls once a day the minimum. Don’t skip weekends.

2. Wash the Box Every Week

Once a week, the ASPCA says to clean all boxes with warm water and unscented soap, baking soda or no soap at all, and replace the litter. Cornell suggests a mild detergent, then drying the box completely before refilling.

Clumping litter makers give a longer window. Fresh Step’s FAQ suggests a full change about once a month for clumping litter and about once a week for non-clumping.

My take: if your box smells before the month is up, the calendar is wrong for your house. Cornell’s rule is simpler: change it often enough that it looks and smells dry and clean.

3. Use the Right Cleaner

Cornell warns against cleaners containing ammonia or vinegar, because they smell like urine and can irritate. The ASPCA adds that scented cleaners can make a cat avoid the box.

Plain, mild, unscented. That’s the whole rule, and I’d apply it to the floor around the box too.

4. Add a Box

Both the ASPCA and Cornell recommend one box per cat, plus one extra. Two cats means three boxes.

Put them in different spots. Don’t bother lining up three boxes in one closet: Cornell suggests boxes in different areas of the house, in quiet, private places away from where your cat eats.

5. Replace an Old Box

Cornell’s advice is to replace boxes that smell or are cracked. If you’ve scrubbed it and it still smells the moment it’s empty, I’d stop scrubbing and buy a new one.

6. Get the Litter Depth Right

The ASPCA says many cats prefer 1 to 2 inches of litter rather than 3 to 4. Fresh Step, writing about its clumping litter, says thin layers stop clumps forming and suggests 3 to 4 inches.

So there’s tension here. I’d use the fill level on your litter’s bag, add litter each time you scoop, and watch whether your cat digs happily. If clumps break apart, see our guide to cat litter not clumping urine.

7. Choose Unscented Litter

Most cats prefer unscented, clumping litter, according to the ASPCA. Cornell also points to unscented, finer-textured litter.

Scented litter is for people. Honestly, if your nose needs a scent to cope, the box needs scooping instead.

8. Rethink Covers and Liners

The ASPCA’s advice for cats with box problems is to remove covers and liners. Cornell explains why: an uncovered box lets odor escape, and a hood traps it inside, right where your cat breathes.

A cover makes the room smell better to you. It doesn’t make the box smell better to the cat.

9. Clean Accidents With an Enzyme Cleaner

If your cat has peed outside the box, that spot is part of the smell. The ASPCA recommends an enzymatic cleaner made to neutralize pet odor, and warns that ammonia-based cleaners can draw a cat back to the same place.

Clean it soon. Cornell says odor must be neutralized, not just masked.

Can a Cat Litter Box Have No Smell?

Close to it. My view: a box that’s scooped daily and washed weekly should smell faintly at most, and only right after use.

If you’re doing all of the above and the smell is still strong, look at the box itself and at your cat. An automatic box needs its own routine, which our Litter-Robot cleaning guide covers.

When a Smell Means a Vet Visit

A sudden change matters more than the smell itself. Cornell lists kidney disease, thyroid disease and diabetes as conditions that often increase drinking and urination, which means more and bigger clumps. Cats with medical problems don’t always look sick.

Call your vet if you notice:

• many more or much larger urine clumps than usual
• frequent trips to the box with little urine
• blood in the urine, crying while peeing, or peeing outside the box

Treat this one as an emergency: a cat straining to pee with little or nothing coming out. Cornell calls urethral obstruction an absolute emergency, more common in male cats, and says death can follow in less than 24 to 48 hours once urine flow is completely blocked. Don’t wait to see if it passes.

This page can’t diagnose anything. It can only tell you when to call.

More litter help lives in Litter & Litter Boxes.

Frequently Asked Questions

How Often Should You Change Cat Litter Completely?

The ASPCA says to wash the box and replace the litter weekly. Fresh Step suggests about once a month for clumping litter. Change it sooner whenever it no longer looks and smells clean.

Does Baking Soda Help Litter Box Smell?

The ASPCA lists baking soda as an option for the weekly box wash. Avoid scented additives, since many cats prefer unscented litter.

Why Does My Litter Box Smell Even After I Scoop It?

The box may be old and scratched, the litter may need a full change, or you may need another box. Cornell suggests replacing boxes that still smell after cleaning.

Is It Bad to Use a Covered Litter Box?

Many cats prefer uncovered boxes, according to Cornell, because odor escapes and they can see around them. The ASPCA suggests removing covers for cats with box problems.

Can I Clean a Litter Box with Vinegar?

Cornell advises avoiding ammonia and vinegar cleaners because they smell like urine. The ASPCA recommends warm water with unscented soap or baking soda for the weekly clean.

Last updated: November 10, 2026. Sources: ASPCA: litter box problems, Cornell Feline Health Center: house soiling, Cornell Feline Health Center: lower urinary tract disease and Fresh Step FAQ.