Litter Box Smell: How to Control It (ASPCA Routine)

A litter box will always smell a little. But if you can smell it from the next room, or the smell has spread to the carpet and walls around it, something in the routine needs to change. The good news is that most litter box smell comes down to a few things you control: how often you scoop, the litter you use, how you wash the box, and where it sits.

This guide is based on the ASPCA’s litter box guidance and the Cornell Feline Health Center. Getting it right matters for more than smell: the ASPCA notes that a box a cat finds unpleasant is one of the common reasons cats stop using it.

1. Scoop every day

The ASPCA advises scooping the litter box at least once a day. Waste left in the box is the main source of smell, and a dirty box can also put a cat off using it. If you have more than one cat, or the box gets heavy use, scooping twice a day helps.

Tie the scooped waste in a bag and take it out of the house rather than leaving it in a bin next to the box.

2. Wash the box and change all the litter weekly

Scooping does not remove everything. The ASPCA recommends that once a week you clean all litter boxes with warm water and unscented soap, baking soda or no soap at all, and completely replace the litter.

1. Empty all the litter into a bag.
2. Wash the box with warm water and unscented soap or baking soda. Wear gloves.
3. Rinse well and dry the box completely.
4. Refill with fresh litter.

Plastic boxes get scratched over time, and scratches can hold odor. If a box still smells right after a proper wash, it may be time to replace it.

3. Choose the right litter, and the right amount

• Clumping and unscented. The ASPCA says most cats prefer clumping, unscented litter. Clumps make it easy to remove all the urine each day, which is what controls smell.
• Skip the scented litter. It may smell nice to you, but cats have a much stronger sense of smell, and a scent they dislike can put them off the box.
• Keep it shallow. The ASPCA notes most cats like a shallow bed of litter, one to two inches rather than three to four.
• Change brands slowly if you switch, so your cat gets used to it.

4. Enough boxes, big enough

• One per cat, plus one. The ASPCA recommends having one litter box for each cat in your household, plus one extra. Fewer boxes mean each one gets dirty faster.
• Size matters. The ASPCA says the majority of cats prefer large boxes that they can enter easily.
• Lids and liners. The ASPCA notes most cats do not like box liners or lids. A lid can trap the smell inside for your cat, even if it hides it from you.

5. Put the box in the right place

The ASPCA says cats like their litter boxes in a quiet location that is not “cornered”, with more than one escape route. A spot with a little airflow also helps smell clear. Keep boxes away from your cat’s food and water. In a home with more than one floor, put a box on each floor.

6. Clean the area around the box

If the room smells even when the box is clean, check around it. Cats sometimes miss the box, kick out wet litter, or go just outside it. Use a UV black light in a dark room to check the floor, the wall behind the box and any nearby carpet. Our black light guide explains how.

• A washable mat under the box catches litter and small spills.
• Treat any urine you find with a pet odor product, following the label. Cornell says odors must be neutralized, not just deodorized to escape a cat’s keen sense of smell.
• Avoid ammonia and vinegar near the box. Cornell advises against them because they smell like urine and can be irritating.

For spots on carpet, see our cat urine guide.

Litter scattered across the floor? See how to stop cat litter tracking and clean up around the box.

For a ferret’s litter tray, which needs a different routine and litter, see how to clean a ferret cage, litter tray and hammocks.

What does not help

• Air fresheners and scented sprays near the box. They cover the smell for you, and a strong scent near the box can put your cat off it. Scooping and washing are what actually remove the smell.
• Strong-smelling cleaners. The ASPCA warns that your cat could develop an aversion to the scent of cleaning products used on the box.
• Adding more litter instead of changing it. Deeper litter does not absorb smell better, and most cats prefer it shallow.

When the smell is a warning sign

Talk to your veterinarian if the smell of your cat’s urine changes suddenly, if your cat is going much more or less often, or if they start going outside the box. The ASPCA says the first step with litter box problems is to rule out a medical cause. If your cat is peeing on walls or furniture rather than the floor, that may be marking; see our guide to cat spraying.

Using an automatic box? See how to clean a self-cleaning litter box for the waste drawer, sensors and base.

A simple routine

• Daily: scoop each box, take the waste outside, sweep up loose litter.
• Weekly: empty, wash with unscented soap or baking soda, dry, refill with fresh unscented litter.
• Monthly: check around each box with a black light and treat any spots.

For accidents around the box, our Pet Cleanup Kit includes gloves, an absorbent powder, a stain and odor foam, a brush and a black light.

Frequently asked questions

How often should I change cat litter?

The ASPCA advises scooping at least once a day and completely replacing the litter once a week, when you wash the box.

What is the best litter for smell?

The ASPCA says most cats prefer clumping, unscented litter. Clumping litter lets you remove all the urine every day, which is what keeps smell down.

Do covered litter boxes reduce smell?

They can hide it from you, but they also hold it inside for your cat. The ASPCA notes most cats do not like lids on their boxes.

Why does my house smell like cat pee even though the box is clean?

Usually because of urine outside the box: on the floor beside it, the wall behind it, or elsewhere in the home. Check with a black light and treat any spots you find. If your cat has started going outside the box, see your veterinarian.

Sources

• ASPCA: Litter box problems
• Cornell Feline Health Center: Feline behavior problems: house soiling

This guide is general information. Talk to your veterinarian about any change in your cat’s litter box habits.