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?
Flush toilet (standard cistern)
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
Fed from a header tank rather than the mains, it needs a low-pressure fill valve and fills more slowly. Greywater reaches it through a diversion to the cistern.
The ordinary toilet: a cistern of drinking water that is flushed to carry waste into the drain. It is familiar and needs nothing new, but it uses clean drinking water for a job that does not need it.
Build it
This solution is not buildable as a DIY project.
Cost
Low
Upkeep
Occasional
Skill to build
Basic
Lifespan
Decades for the pan; the cistern mechanism is the part that fails and it is replaceable
Embodied carbon
Low
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Basic
Regulation (FR example)
Connection to a compliant treatment system is required; where no mains sewer is available, an approved autonomous installation must be in place.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Flush toilet (standard cistern) (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: 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.
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: 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.
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
Project engineering judgement: the conventional baseline fixture
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.