A compostable pet waste bag is one that an independent lab has tested and shown to break down under set composting conditions. A "biodegradable" bag has passed no such test. The catch for dog owners is that the mark only counts if the bag, and the poop inside it, end up in a compost system built for pet waste. For most people that means a dedicated pet-waste composter in their own yard, or it means nothing at all.
"Biodegradable" vs. "compostable": one is a word, one is a test
"Biodegradable" has no legal definition for plastic products in the US. No test is required to print it on a bag. Many bags sold as biodegradable are ordinary polyethylene with an additive that makes the film fall apart faster. They do not turn into soil. They turn into microplastics. The EU restricted this kind of additive plastic (sold as "oxo-degradable") in single-use products in 2019. That is why we do not use the word for our bags.
"Compostable" is different. It means the bag was tested against a written standard, by a lab that does not work for the brand, and passed. The standard sets the conditions (temperature, moisture, time), and the bag has to fall apart, be eaten by microbes, and leave compost that still grows plants. You either pass or you do not get the mark.
Words like "eco-friendly", "earth-friendly", and "green" sit in the first camp. Marketing. No test, no regulator, nothing you can check. For a longer walk through the three words, read Dog poop bags: degradable, biodegradable, or compostable?.
What a certification mark tells you, and what it does not
A real certification mark tells you three things.
- This exact product, at this exact thickness, was tested. The bag as sold, ink and all.
- An independent body ran the test and put its name on it. The main names are TÜV Austria (OK compost marks), BPI in the US, and DIN CERTCO in Germany.
- There is a certificate number you can look up on the certifier's public list.
A certification mark does not tell you what happens to the bag in a trash can. It does not tell you that your city accepts it. And it says nothing about whether the dog poop inside is safe to compost. Those questions matter more than the mark.
There are also two kinds of compostable mark. Industrial marks (tested to standards such as ASTM D6400 in the US and EN 13432 in Europe) cover a hot, managed facility. Home marks cover a backyard pile at ordinary outdoor temperatures. A bag with only an industrial mark may never break down in a backyard composter. If you home compost, the home mark is the one that counts. TÜV Austria OK compost HOME is the common one, and we explain the certifier and the test in What are TÜV Austria compostable bags?.
Where the bag ends up decides everything
Three places a bagged dog poop can go. The certification only matters in one of them.
The trash
This is where most dog poop in the US goes, and it is a fine choice. Landfill is built to keep things sealed, dry, and starved of oxygen. Nothing meaningfully breaks down in there, compostable bag or not. So if the trash is your route, weigh the bag on the walk first: thick film, no leaks, easy to open with cold fingers.
The city green bin
Most municipal and commercial composting programs in the US do not accept pet waste. The reason is pathogens, not the bag. So an "industrially compostable" bag is not a real disposal route for dog poop, whoever makes it. Unless your program says in writing that it takes pet waste, keep dog poop out of the green bin.
A dedicated pet-waste composter
This is the only place a home-compostable mark does anything. And it has rules:
- Keep it separate from your garden compost. Dog poop can carry E. coli, roundworm, and Giardia, and a cool backyard pile does not get hot enough to kill them.
- Use the finished compost on non-food plants only. Ornamentals, hedges, the lawn. Never on anything you eat.
- Pick a system built for the job: an in-ground digester (the Doggie Dooley type), a dedicated bin kept away from food compost, or a bin plus an enzyme or bacteria additive that speeds things up.
The step-by-step, including what to do in winter, is in Compost dog poop: the only guide you will use.
Why the material matters
The material is what gets certified. A standard does not test a promise on a package. It tests the physical film, at the thickness it is sold in, with the ink printed on it. Ordinary plastic with an additive cannot pass, however it is labeled, because the microbes in compost do not eat it.
Thickness is part of the same story. A thinner film is easier to certify and cheaper to make. It is also the bag that rips on a Great Dane walk. Look for a bag that is thick enough to trust and certified at that thickness.
What about cat litter and small pets?
This page is about dog poop. Used cat litter has a shorter answer: it goes in the trash. None of the certification talk above changes that. Pick a litter bag for size, strength, and handles, and tie it tight. For rabbits, guinea pigs, and hamsters, a standard dog poop bag is the right size for cage cleanup.
Common questions
Are compostable poop bags strong enough for big dogs?
The good ones are. Strength comes from film thickness, not from the certification. Our bags are extra thick, and a Judge.me reviewer with a Great Dane described them as "thick enough to not tear." If a bag feels thin on the roll, it will feel thin on the walk.
Can I put a compostable poop bag in my regular garden compost?
No. Not because of the bag, because of the poop. Dog waste carries parasites and bacteria that survive cool composting, and you do not want them near your tomatoes. A dedicated pet-waste composter is the only home option, and the finished compost stays on non-food plants.
Can I put dog poop in the city green bin if the bag is certified?
Almost always no. Most US municipal composting programs reject pet waste outright. Check your program's rules in writing before you assume. The bag does not change the answer.
