Urine-diverting dry toilet (UDDT)

A dry toilet variant: still no water use and no blackwater stream, with urine separated from solids at the source to reduce odor and moisture and let each stream be handled separately (urine is a fast-acting, near-pathogen-free fertilizer once diluted; solids still need the full extended pathogen-safe curing step before use).

Cost

Medium

Upkeep

Frequent

Skill to build

Basic

Lifespan

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.

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

Inputs

none

Outputs

• Compost
• Nutrients

Sources

• General composting-toilet industry/practitioner durability consensus

Tutorials

• https://wiki.lowtechlab.org/wiki/Toilettes_s%C3%A8ches_%C3%A0_s%C3%A9paration_d%27urine/en
• https://wiki.lowtechlab.org/wiki/Toilettes_s%C3%A8ches_%C3%A0_s%C3%A9paration_d%27urine/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.