How to Switch Cat Litter: Clay to Eco-Friendly, Step by Step
How to switch cat litter without a fight: go slowly and let your cat set the pace. Below: a week-by-week plan, what to watch for, and what to do if your cat says no.
Why Go Slowly
Your cat has an opinion about litter. The 2025 iCatCare consensus guidelines on urinary tract disease say cats generally prefer sandy, clumping litter. In a 2025 study in the Journal of Veterinary Medical Science, cats preferred clumping clay. An eco-friendly litter may feel different underfoot from what your cat is used to, and a sudden swap can be a lot to ask.
Mixing the new litter in a bit at a time lets your cat get used to it while the old smell and feel are still there. We found no study that tests a particular schedule, so the plan below is a starting point, not a rule. Your cat decides how fast you go.
A 4-Week Starting Plan
Step by Step
Choose Your New Litter
Pick one that clumps if you can. That is the feel cats generally prefer, and vet guidelines list non-clumping litter as a risk factor for feline idiopathic cystitis, a bladder condition. A few places to start:
- Clumping options: clumping wood fibre, or brands of corn and wheat litter that clump
- After surgery: paper, which the ASPCA names for at least a week after surgery
- Plain wood pellets: they do not clump, so expect a bigger change underfoot
Whichever you choose, do not plan to flush it. California requires every litter sold there to warn against flushing.
Set Up the Box
- Wash the box with unscented soap, since vet guidelines advise keeping heavy scents away from cats
- Keep the box where it is
- Keep the litter about as deep as your cat is used to
- With more than one cat, switch one box at a time
Week 1: A Little New Litter (About 25%)
Mix about one part new litter into three parts old. Your cat gets a hint of the new texture and smell while the box still feels familiar.
Watch for: normal box use. If your cat hesitates or goes elsewhere, use less new litter and stay here longer.
Week 2: Half and Half
Move to roughly half new, half old. Mix the two together rather than layering them, so every scratch turns up both.
Week 3: Mostly New (About 75%)
Three parts new to one part old. If your cat is still unsure, stay at this mix for another week before you go further.
Week 4: All New
Fill the box with the new litter only. Keep watching for another week. If anything changes, go back a step. There is no prize for speed.
Try a Second Box
If you have room, put a second box with the new litter next to the old one. Your cat can try it without losing the box it knows. When the new box is in regular use, retire the old one.
Slow Down If You See This
Going next to the box instead of in it, peeing or pooping somewhere else, digging without using the box, or seeming stressed nearby. Step back to the last mix that worked and give it more time. A cat that strains or can't pass urine needs a vet now, whatever litter is in the box.
Special Situations
More than one cat: switch one box at a time and keep at least one box with the old litter until every cat is using the new one.
Picky or anxious cats: take longer than four weeks. Stay at each mix until your cat uses the box without fuss.
Cats recovering from surgery: don't start a switch now. Follow the discharge sheet. The ASPCA names shredded paper, a paper litter or uncooked long-grain rice for at least a week after surgery. See our shredded paper guide.
Cats with bladder trouble: talk to your vet first, and pick a clumping litter.
Smell During the Switch
If the box smells during the switch, scoop every day. The CDC advises changing the box daily anyway. If smell is still the problem, you can add Purrify, an activated carbon additive sold in bags, to whatever litter is in the box. It holds a 5.0 Google rating and is stocked in 40+ pet stores across Canada. See how activated carbon works or the science behind it.
Troubleshooting
Your cat refuses the box after the first mix: you went too fast. Go back to mostly old litter with just a handful of new, and take longer over each step.
Your cat scratches but won't go: the texture may be the problem. If you started with plain pellets, try a clumping litter instead.
Your cat goes beside the box: try an unscented litter. Vet guidelines advise keeping strong scents away from cats.
Signs It Worked
- Your cat uses the box as often as before
- Normal digging and covering
- No accidents outside the box
- Your cat seems relaxed around the box
What If It Doesn't Work?
Some cats just say no to a litter. If yours turned down pellets, try one that clumps. If the smell seemed to put your cat off, try an unscented one. Still refusing after that? Go back to what worked and ask your vet.
Not sure which eco-friendly litter to try next? Our cat litter alternatives page compares all eight types, and the biodegradable cat litter guide covers what happens to each one after use.