Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?
Living toilet (urine-diverting, larvae-processed)
Passive
One of 5 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
What your site needs
A room that stays above roughly 20 C, or the larvae go dormant and the bin stops working. The experiment saw exactly that in October. A separate container for the diverted urine, and somewhere for the finished substrate to go. No plumbing, no drain and no supply, but the bin sets the fixture's footprint rather than the pan: in the flat it ran, the bin's length decided where the toilet could be, and it ended up next to the kitchen
A dry toilet that separates urine and lets fly larvae eat the solids inside its own bin. In days rather than months, the larvae turn the waste into a fine, odourless material. It suits a flat, where there is nowhere to compost, but the larvae slow down in a cold room.
The larvae bin is the wearing part and the rest is joinery. The Boulogne-Billancourt build used a PLA bin that cracked at the folds inside the four months; the report's own recommendation is stainless steel, which would outlast the toilet around it
Embodied carbon
Low
Space / material use
Medium
Output timing
Continuous process
Skill to repair
Basic
Regulation (FR example)
Dry toilets are explicitly permitted (arrete du 7 septembre 2009 modifie) but must be declared to the SPANC, and byproducts must be composted on the property without discharge or nuisance to neighbours. In a flat that last condition is the whole difficulty, and it is what this design answers: the transformation happens inside the bin rather than in a heap outdoors. Where the substrate finally goes is still the household's problem to solve
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Living toilet (urine-diverting, larvae-processed) (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Heavy · Change to daily life: Way of living · Works without the grid: Yes Choose it if you live in a flat with nowhere to compost and want waste turned odourless in days.
Composting toilet (dry) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: Regular · Change to daily life: Way of living · Works without the grid: Yes Choose it if you want to use no water at all and make compost from the waste.
Low-flush toilet Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Light · Change to daily life: None · Works without the grid: Yes Choose it if you want nothing to change in use, with less water per flush.
Urine-diverting dry toilet (UDDT) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Regular · Change to daily life: Way of living · Works without the grid: Yes Choose it if you want a dry toilet with fewer smells, and urine as a quick garden fertiliser.
Flush toilet (standard cistern) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Light · Change to daily life: None · Works without the grid: Yes Choose it if you want the standard toilet every plumber knows, on mains water and sewer.
We don’t list sizing or quantities, as the yield of each technique depends on the quality of its build. The catalogue compares options but doesn’t dimension them. Regulatory notes are indicative, with a French example, and need to be confirmed locally.