Composting toilet (dry)

Also called a dry toilet: no water use at all (a scoop of sawdust or similar carbon material after each use instead of a flush), so it produces no blackwater stream to collect or treat, blackwater treatment and solids handling are both bypassed entirely, not just simplified. The raw output is not yet safe to use, though, see the extended pathogen-safe curing entry for the required step before it's treated as finished compost.

Cost

Medium

Upkeep

Frequent

Skill to build

Basic

Lifespan

Unit/chamber: 15-20 years for a well-built wood or durable-plastic composting toilet body

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.

Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.

Inputs

none

Outputs

• Compost
• CO2

Sources

• General composting-toilet industry/practitioner durability consensus

Tutorials

• https://wiki.lowtechlab.org/wiki/Toilettes_s%C3%A8ches_familiales/en
• https://wiki.lowtechlab.org/wiki/Toilettes_s%C3%A8ches_familiales/fr

What this page does not tell you

No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.