Dry toilets — also known as composting toilets — fit perfectly with the ethos of tiny living. Environmentally friendly, simple to use, no plumbing required, and a clear answer to one of the biggest challenges of off-grid life: what to do with human waste in a space the size of a garden shed.
For tiny house owners, vanlifers and boat dwellers, a compost toilet makes sense in so many ways. No water tank to lug around for flushing. No black-water tank to dump. No sewage hookups to find. And as a bonus, the system captures valuable nutrients that can be used as fertiliser rather than discarded as sewage.
The make-or-break component: the urine separator
Browse any tiny-house forum thread on composting toilets and you'll see the same theme repeated: the difference between a system that works and one that smells terrible comes down to one thing — the urine separator.
Mix urine and faeces together and ammonia-producing bacteria thrive. Keep them separate — with the urine diverted into a sealed container at source — and the smell vanishes. That's all a urine separator does, and it's the cheapest, simplest answer to the most common reason DIY compost toilets fail.
An affordable alternative to commercial composting toilets
There are off-the-shelf composting toilets on the market — the Separett, Nature's Head, Air Head and similar units — and they're generally well-engineered. But at £700–2,000 a unit, they're a significant chunk of a tiny-house budget.
The DIY route is dramatically cheaper. A bucket, a length of waste pipe, a sealed urine container, and a We-Pee urine separator at £31. Build a wooden box around it (some plywood, a toilet seat, and a few hours) and you've got a working compost toilet for under £100 of materials.
For the full step-by-step build with materials list, see our complete guide to building a composting toilet.
Tiny house customer installs
We've supplied separators to tiny-house builders across the UK, US (Texas, Hawaii, the Northern states), New Zealand, Australia and beyond. Have a look at our Customer Installs gallery for real builds in the wild.