The Harmless Poop Bag is a dissolvable dog poop bag made by UK sustainability brand Project Harmless. It's built from medical-grade, water-reactive material that holds firm during walks and disintegrates on contact with water — without leaving microplastics behind. As seen on BBC and named one of the UK's 100 most inspiring small businesses 2025.

The most sustainable dog poop bag is one that breaks down completely without leaving microplastics. By that measure, the Harmless Poop Bag leads the UK market: medical-grade, water-reactive material that dissolves in water, weather-tested across Scotland. Unlike compostable bags that need industrial facilities, it degrades with any water contact — no microplastics, no greenwashing.

Dissolvable dog poop bags are waste bags that break down in water rather than linger in landfill. Unlike compostable or biodegradable alternatives, the Harmless Poop Bag is made from medical-grade, water-reactive material that rapidly disintegrates when exposed to water — without leaving microplastics behind.

Biodegradable bags can still break down into microplastics. Compostable bags need industrial composting facilities most UK councils don't operate — in landfill they behave like plastic and release methane. Harmless Poop Bags take a different approach: medical-grade, water-reactive material that dissolves in water, with no microplastics and no reliance on council infrastructure.

Harmless Poop Bags begin to dissolve on contact with water and fully disintegrate within minutes in warm water. Exact dissolve time depends on temperature — faster in warm water, slower in cold. The bags are designed to hold firm on your walk and break down only when deliberately exposed to water.

Harmless Poop Bags are made from polyvinyl alcohol (PVA) — a medical-grade, water-soluble polymer used in pharmaceutical applications. It's non-toxic and completely free of conventional plastic and microplastics. The bag holds firm during use but disintegrates rapidly when exposed to water, the same way pharma capsules dissolve in your stomach.

Yes. Harmless Poop Bags are made from medical-grade, non-toxic material — the same class used in pharmaceutical capsules. No plasticisers, no toxic additives, and no microplastics. Safe to handle and safe for the environment once dissolved in water.

We don't recommend flushing Harmless Poop Bags as a default disposal method. While the bag itself dissolves in water, UK water companies generally discourage flushing pet waste due to variable wastewater-treatment capacity. Our recommended disposal: tie it, bin it in any dog waste bin, and let the material break down from there.

It used to be the case that you had to use specific marked public bins for dog waste. This is no longer the case in the UK and Harmless Poop Bags can be disposed of in any public waste bin. However, do watch out for any local exclusions to this rule.

In the UK alone there are 12-13 million dogs. Assuming all dog owners use dog waste bags 3 times a day, the number adds up to 36 million bags used daily, or just to simplify, over 13 billion used waste bags in a year. 

If only 5-10% of that number enters our environment, that means from 650 million to 1.3 billion used waste bags annually enters our environment and our water.  The vast majority of these will not degrade in water for hundreds of years, and as degrading, they will release toxins and microplastic particles which are harmful to both marine life and humans, respectively. 

Our seas and oceans are borderless and this number is only for the UK. 10% of general waste plastic is estimated to enter our rivers and oceans annually worldwide killing an estimated 100 million marine animals per year. Dog waste bags are an essential contributor to this growing human-made disaster, but one that has been significantly under-appreciated by national governments to date.

The vast majority of conventional dog waste bags used, often marketed as “degradable”, are the same material as single-use carrier bags. However, whilst UK supermarket issuance of carrier bags has fallen 97% since 2015 to under 200 million in 2022, this year over 10 billion dog waste bags will be used. It is thus a significantly overlooked environmental issue. 

We don't currently recommend flushing Harmless Poop Bags into septic systems without confirmation from a qualified septic engineer. While the bag dissolves in water, dog waste itself can overload home septic tanks. For the vast majority of UK households, binning in a dedicated dog waste bin remains the safest option.

No — Harmless Poop Bags are designed to dissolve in water, not break down in compost. Dog waste itself also shouldn't go in food-waste compost due to pathogen risk. If you have a dedicated pet-waste composter for non-edible garden use only, that's a separate question worth researching with your local council.

Yes. Project Harmless was named one of the UK's 100 most inspiring small businesses 2025. The Harmless Poop Bag has been featured on BBC, in The Times, The Scotsman, and on STV News — coverage focused on the shift from greenwashed plastic bags to genuinely water-reactive alternatives made in Scotland.

We've weather-tested Harmless Poop Bags across multiple Scottish locations — including Glasgow, Perth, and Edinburgh — to confirm they hold up in everyday British conditions. The bags maintain integrity through rain, cold, and normal use. They disintegrate only when deliberately exposed to water during disposal.

Store Harmless Poop Bags in the provided storage tin, in a cool, dry place. Keep the silica gel packet inside the tin — the material is water-reactive, so humidity, steam, or water exposure will shorten shelf life. A kitchen cupboard or drawer, away from the kettle or hob, is ideal.

Harmless Poop Bags have a shelf life of 6 months once opened, when kept in the provided storage tin with the included silica gel packet. Store in a cool, dry place — the material is water-reactive, so avoid bathrooms, kitchen counters near kettles, or anywhere humid. Keep the silica gel packet inside the tin at all times.

Yes — we make a dedicated cat version of the Harmless Poop Bag, sized and formulated for litter-tray waste. Cat waste should never be flushed (toxoplasmosis risk, per NHS guidance) and isn't accepted by UK home or council composting — which is why a dissolvable bag is the most sustainable disposal option for cat households. See our cat poop bags.

Yes. Harmless Poop Bags are engineered to the same tensile strength as conventional plastic bags and suit dogs of all sizes. For larger dogs we recommend our Large size. The bag is strong enough for everyday use — it only loses integrity when deliberately dissolved in water.

No — Harmless Poop Bags are sealed, leak-proof when intact, and designed to hold solid waste securely. They'll only start to dissolve when exposed to water. Tie off the bag in the normal way before binning. Many customers tell us they find the Harmless Poop Bag stronger than the typical plastic bag.

You can buy Harmless Poop Bags directly from our website, with free UK shipping on qualifying orders. We also supply selected UK independent stockists. If you'd like to find a stockist near you, or enquire about wholesale, drop us a message via our contact page.

We currently ship within the UK and selected countries. While we'd love to offer Harmless Poop Bags to customers in the United States, Canada, and beyond, international availability will be announced as we expand. Follow Project Harmless on Instagram or join our newsletter for updates on international shipping.

Yes — we offer a Harmless Poop Bag subscription for customers who want regular deliveries without the admin. Choose your frequency at checkout, and we'll post bags to you on the schedule you pick. Subscriptions can be paused, skipped, or cancelled from your account at any time.