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?
Ceramic candle filter (silver-impregnated)
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 pot or candle of fired clay, treated with silver, that water slowly drips through by its own weight. The fine pores hold back dirt and most bacteria, and the silver kills germs. It makes drinking water with no power or pump, one or two litres an hour per candle, but it does not remove chemicals.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Ceramic candle filter (silver-impregnated) (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: Regular · Change to daily life: Daily · Works without the grid: Yes Choose it if you want drinking water with no power from a pot on the counter, with nothing to build.
Multi-stage filtration + UV disinfection Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Heavy · Change to daily life: None · Works without the grid: No Choose it if you want the whole house on safe drinking water from rain or raw water.
Bio-sand filter Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Regular · Change to daily life: Daily · Works without the grid: Yes Choose it if you want safe drinking water with no electricity, from a filter you can build.
Reverse osmosis (RO) filtration Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Specialist · Upkeep: Heavy · Change to daily life: None · Works without the grid: No Choose it if your water carries nitrates, metals or salts and you want the purest drinking water.
Solar still (solar distillation) 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: Daily · Works without the grid: Yes Choose it if your only source is salty or badly polluted and you have sun.
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.