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?
Urine-diverting dry toilet (UDDT)
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.
A dry toilet that separates urine at the front from solids at the back. Keeping the two apart cuts smells and moisture, and each is dealt with on its own. It uses no water, and diluted urine makes a quick-acting garden fertiliser; the solids still need a long curing period. It can be built in with its own containers, or made as a removable wooden box that sits on an ordinary toilet: nothing in the bathroom changes, which suits a flat, and it is the version rated here. The box sends the urine down the toilet's own bowl, so it gives no fertiliser.
15-20 years for the unit body, same range as the composting toilet; the urine-diverting insert is a smaller, earlier-replaced part
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 any discharge or nuisance to neighbours.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Urine-diverting dry toilet (UDDT) (This page) 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 a dry toilet with fewer smells, and urine as a quick garden fertiliser.
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.
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.
Living toilet (urine-diverting, larvae-processed) 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.
Sources
General composting-toilet industry/practitioner durability consensus
Limitations of this page
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.