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?

Permitted discharge to soil/drainage field

Passive

Note: Cost, carbon and footprint are broad judgements against comparable building approaches, not measured figures.

What your site needs

Soil percolation rate and area sufficient for a code-compliant drainage field, plus enough fall from the outlet to the field to avoid a lift pump

A buried field of perforated pipes in gravel that lets cleaned used water soak slowly into the ground, where it is not reused. The soil finishes cleaning it. It is the legal way to return the water to the ground safely. It needs no pump where the field lies lower than the treatment outlet.

Build it

This is contracted work rather than a self-build.

Cost
Low
Upkeep
Seasonal
Skill to build
Specialist
Lifespan
Drainage field: 20-30 years before soil clogging ("biomat") reduces infiltration and the field needs rest or replacement
Embodied carbon
Low
Space / material use
Low
Output timing
Continuous process
Skill to repair
Intermediate
Regulation (FR example)
On-site sanitation (assainissement non collectif): the installation must be declared to and approved by the local SPANC before work starts, and is subject to periodic inspection. Arrete du 7 septembre 2009 modifie.

Inputs

Outputs

none

How does this solution compare to others for the same need?

The only option catalogued for this need so far, so there is nothing to compare it against.

Sources

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.