How many clumps a day
Scoop at the same time every day and write the number down. A count that climbs over a fortnight is worth a phone call, and it is information your vet cannot get from a single visit.
Living With a Diagnosis
Cat Litter When Your Cat Has Kidney Disease
Use an unscented litter that clumps hard enough to lift out whole. Failing kidneys mean more urine, and clumps you can count and see the size of turn the litter box into a daily record your vet can use. Your vet leads the treatment; this page is only about the box.
9 min read•Updated Aug 22, 2026
Why the box changes at all
Cornell Feline Health Center puts it plainly: as the kidneys lose their ability to concentrate urine effectively, cats may begin to urinate greater volumes and drink more water to compensate. More liquid, same box. Everything on this page follows from that one sentence.
Three things the box can tell you
How big they are
One clump the size of a fist is a different message from four small ones. Both matter. A litter that shatters when you lift it hides the size completely.
Anything that looks wrong
Colour, blood, a clump that will not form. You are not diagnosing anything. You are noticing, so somebody qualified can look at it early.
A phone note works fine. Date, number of clumps, anything unusual. Take it to the next appointment. Vets get more out of four weeks of counts than out of a single sentence about the cat seeming to pee more.
Which litters leave you something to count
This is the whole shortlist question. A litter that shatters under the scoop, or that does not clump at all, gives you no way to see what changed. Everything we have tested, strongest clumping first.
| Litter | Type | How it clumps | Can you track output? |
|---|---|---|---|
| Dr. Elsey's Cat Attract | Clumping Clay | Rock-solid | Clumps hold whole |
| Dr. Elsey's Ultra | Clumping Clay | Rock-solid | Clumps hold whole |
| Boxiecat Premium | Premium Clumping Clay | Flat-top easy scoop | Clumps hold whole |
| Sustainably Yours | Natural Corn + Cassava | Excellent for natural litter | Clumps hold whole |
| World's Best Cat Litter | Corn Litter | Excellent for corn | Clumps hold whole |
| Arm & Hammer HardBall | Fast-Clumping Clay | Hard and fast | Clumps hold whole |
| Naturally Fresh Walnut | Walnut Shell | Hard for natural litter | Clumps, but some break up |
| Arm & Hammer Clump & Seal | Scented Clumping Clay | Good | Clumps, but some break up |
| Fresh Step Scented | Scented Clumping Clay | Decent | Clumps, but some break up |
| Arm & Hammer Super Scoop | Budget Clumping Clay | Solid budget clumps | Clumps, but some break up |
| Tuft + Paw | Soy / Tofu | Good | Clumps, but some break up |
| Catalyst Soft Wood | Soft Wood / Pine | Good for wood litter | Clumps, but some break up |
| Frisco by Chewy | Budget Clumping Clay | Acceptable | Clumps, but some break up |
| Purina Tidy Cats | Budget Clumping Clay | Average | Clumps, but some break up |
| PrettyLitter | Silica Crystal | Non-clumping | Nothing to count |
| Feline Pine | Pine Pellet | Non-clumping pellets | Nothing to count |
| Ökocat Paper Pellet | Paper Pellet | Non-clumping pellets | Nothing to count |
Scented bags are out regardless of where they sit in that table. A cat that is already unwell is the last cat you want turning against its box.
About the colour-change crystals
Some crystal litters are sold around health monitoring, changing colour in response to what lands on them. Treat a colour change as a reason to book an appointment, never as a result. It does not measure kidney function, and a normal colour is not an all-clear.
There is also a practical catch for this specific situation: crystals absorb rather than clump, so you lose the count. If your vet has asked you to watch output, a clumping litter does that job better.
What we found testing PrettyLitterFour changes to the setup
Add a box
More urine and more urgency. A second or third box on the floor where the cat spends its day cuts the distance when it cannot wait.
Scoop twice a day
Once for the count in the morning, once so the box is usable by evening. The bag will not last as long as the label says, and that is expected.
Keep the sides low
Cats with a long-term illness often have sore joints as well. A high rim turns urgency into an accident on the floor beside the box.
Change one thing at a time
If you are moving to a new litter, mix it in over a week. A sick cat has less patience for a strange box than a well one.
ReviewCatLitter editorial teamUpdated Aug 22, 2026
This page is about the litter box, not about treatment. The line on urine volume is quoted from the Cornell Feline Health Center page linked above; the clumping figures are our own testing. Diagnosis and care belong with your vet, and nothing here should delay an appointment.
Questions people ask
- What litter is best for a cat with kidney disease?
- An unscented litter that forms clumps strong enough to lift out whole, so you can count and see the size of what your cat is producing. Cornell notes that as the kidneys lose the ability to concentrate urine, cats may urinate greater volumes and drink more to compensate. A litter that hides that change costs you the earliest signal you have.
- Does a cat with kidney disease need more litter changes?
- Usually yes, because there is more urine going into the same box. Expect to scoop more often and to replace the litter sooner than the bag suggests. Nothing about the disease changes what the litter is made of, only how fast it fills up.
- Can litter detect kidney disease?
- No. Some crystal litters change colour and are marketed around health monitoring, but a colour change is a prompt to see a vet, not a result. Diagnosis is blood and urine testing at a clinic, and nothing in a bag replaces that.
- Should the litter be scented for a cat drinking more water?
- No. More urine in the box makes a scented litter smell stronger, not cleaner, and a sick cat that starts disliking the box is a much bigger problem than the smell. Unscented, more often.