Biodegradable Cat Litter: What Actually Breaks Down

By EcoCatLitters editors · Published 6 October 2026

Biodegradable cat litter is litter made from plant material - wood, paper, corn, wheat, grass and so on - instead of mined clay. The plant part can break down. Clay can't: one company that makes clay litter says its clumping litter "is not biodegradable." But "biodegradable" on a bag promises less than most people think, and where the used litter ends up decides whether it ever breaks down at all. Below is what the sources say, and where they go quiet.

Which cat litters are biodegradable?

Any litter made from plants is made of material that can break down. Clay litter (bentonite) and other mineral litters are not. Here are the plant-based types, with a full guide to each:

Check the binder, too. Clumping clay litter clumps because of bentonite. Plant clumping litters use plant binders instead: a US Department of Agriculture study calls guar gum "the principal gum used ... as a clumping agent in biodegradable cat litters."

How long does biodegradable cat litter take to break down?

Nobody we could find has published a tested number. You will see claims like "paper breaks down in two to three months" or "corn in 90 days." We looked for the study behind each one and found only pages repeating each other. So we are not giving you a number.

What is on record is the landfill problem. Litter you throw in the trash ends up in a landfill, and the US Federal Trade Commission, which polices green claims, says landfills "do not present conditions in which complete decomposition will occur within one year." A bag of plant litter in a landfill is still plant litter for a long time.

What "biodegradable" on the bag is supposed to mean

Under the FTC's Green Guides, a plain "biodegradable" claim needs proof the product will "completely break down and return to nature ... within a reasonably short period of time after customary disposal." For litter, customary disposal is usually the trash. Treat the word as a description of the material, not a promise about your garbage.

Litter bags are a separate question

The bag you scoop into has its own labelling rules. California does not allow plastic products to be sold labelled "biodegradable," and bags sold as compostable there must meet a certification standard, according to CalRecycle. A "compostable" claim, under FTC rules, also has to say so if the item cannot be composted at home or if most buyers have no composting facility nearby.

Clay vs plant litter: where each comes from

Clay: a mined mineral

Clumping clay litter traditionally relies on sodium bentonite, the USDA says. According to the US Geological Survey, 48% of the bentonite used in the US goes to pet waste absorbents, and the US sold or used an estimated 4.1 million metric tons of bentonite in 2025. Our own arithmetic from those two USGS figures: 48% of 4.1 million is about 2 million metric tons of bentonite for pet waste absorbents in 2025.

Wyoming holds as much as 70% of the world's known supply. The Wyoming State Geological Survey says surface mining to about 50 feet deep accounts for all of the state's bentonite production, and its 2014 summary put kitty litter at 25% of Wyoming bentonite use.

To be fair to the mines: the US Bureau of Land Management says several Wyoming bentonite operators have won its reclamation awards for restoring land. Mining leaves a mark, but "the land never recovers" is not what the record shows.

Plant litter: grown, not dug

The USDA's Agricultural Research Service built an experimental litter from eastern red cedar flakes, guar gum and food-grade mineral oil to replace bentonite as the clumping agent. Its follow-up reported the cedar formula cut dust by 60% compared with traditional litters containing sodium bentonite clay.

What your cat thinks

Cats get a vote. The 2025 iCatCare consensus guidelines say cats generally prefer a sandy, clumping-style litter, and list non-clumping litter among the risk factors for feline idiopathic cystitis, a bladder condition. In a 2025 study in the Journal of Veterinary Medical Science, cats preferred clumping clay litter. If you move to a plant litter, a clumping one may be easier on your cat, and a slow change helps - our switching guide walks you through it.

The other common reason people slide back to clay is smell. Plant litter can be topped with Purrify, an activated carbon additive sold in bags, so you can keep the plant litter and still deal with the smell. Read how activated carbon works on litter box odor.

How to dispose of biodegradable cat litter

"Biodegradable" makes people want to put used litter in the garden. The sources say no.

Not in a home compost pile. A USDA conservation guide on composting pet waste says: "We do not recommend adding cat waste or cat litter to your compost." The EPA says waste from meat-eating pets belongs in the garbage because composting does not readily destroy its parasites, bacteria and viruses.
Not in the yard. Toxoplasma eggs (oocysts) from cat feces can survive in moist soil for up to 18 months, according to a 2019 scientific review. Dr. Elsey's also tells buyers to keep its clay litter out of the yard and garden.
Not down the toilet. California requires every cat litter sold in the state to carry a do-not-flush warning. Our flushable cat litter guide explains why, including the link to sea otters.
Check your city's green bin. Rules differ. Toronto's Green Bin accepts clay and wood pellet cat litter. Seattle says cat litter and poop must always go in the trash. Look up your own city before you switch bins.
Otherwise: sealed bag, trash. That is what the EPA, UC Davis researchers and Seattle Public Utilities recommend.

Biodegradable cat litter questions

Yes. Litters made from plant material - wood, paper, bamboo, corn, wheat, walnut shell, tofu or grass - are made of things that can break down. Clay litter is not: one clay litter maker says its clumping clay "is not biodegradable." How fast plant litter breaks down depends on where it ends up.

No. Dr. Elsey's, which makes clumping clay litter, says its litter "is not biodegradable and should not be disposed of in the yard or garden whether it has been used or not." The USDA describes sodium bentonite clay as the clumping agent traditionally used in cat litter.

It depends on what makes it clump. Clay clumping litter uses bentonite and is not biodegradable. Plant clumping litters use plant binders instead. A USDA study calls guar gum "the principal gum used ... as a clumping agent in biodegradable cat litters."

We could not find a sourced figure for any litter material. Numbers like "two to three months" circulate online without a test behind them. What is on record: the US Federal Trade Commission says landfills "do not present conditions in which complete decomposition will occur within one year." So bagged litter in the trash breaks down slowly, whatever it is made of.

Clay will not biodegrade. Plant litter can break down, but not on a set schedule, and a landfill slows it down. Some plant litters soften in water, which is why they get sold as flushable - see our flushable cat litter guide for why that is a different problem.

Scoop daily, seal it in a bag and put it in the trash, unless your city's green bin takes it. Toronto's Green Bin accepts clay and wood pellet cat litter, but Seattle says cat litter always goes in the trash. Do not compost it at home or flush it. Details in our cat litter disposal guide.

Some corn and wheat litters are sold as flushable. California law requires every cat litter sold there to tell buyers not to flush it, and UC Davis researchers advise against flushing cat waste. Read what happens after you flush.