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Biological wastewater treatment using reeds at Ecovillage Sieben Linden, Germany. The installation is a shallow basin that receives a mixture of greywater and urine but no humanure. Treated water is used for irrigation. Photo taken by OSE contributor Rasmus Kiehl at Ecovillage Sieben Linden, Germany.

Good Gray Water Summary

Strategic Planning

Source Control -> Plumbing and Pipesystem -> Pre-Treatment -> Treatment -> Post-Treatment(?)

extensive planning help, tips and tricks:

From the University of Natural Resources and Applied Life Sciences (BOKU), Vienna

For the new-house builder

Things to consider

1)hydraulic load 2)load of easily degradable organic matter and BOD (biochemical oxygen demand)

ad1)maximum load of water: estimated gray water amount for one person (incl. rain/storm water for mulch basin and planted soil filters):

see also: Percolation Test

ad 2)possible properties of gray water: Organic Compounds Pathogens Nutrients Metals/Toxins

3)Source Control: water-conservation methods

4)Duckweed has excellent capabilities for greywater purification and should be considered as a component of a treatment system.

Tests and Preparations

Percolation Test: to determine the water absorption rate of the soil In general, soils are classified as clay soils, sandy soils, or loamy soils. Clay is nutrient rich, but slow draining. Sand is quick draining, but has trouble retaining nutrients and moisture. Loam is generally considered to be ideal soil because it retains moisture and nutrients but doesn’t stay soggy.


Treatment Methods

laundry to mulch basin system (


It's the simplest, most economical residential greywater system—design open source franchise including: Introduction Design Calculator Parts Parts sources Maintenance Installers Installations photo album Comments

Online e-Books

Graywater Guide Book (Department of Water Resources of California)

Septic Systems Owner's Guide Book (Grand Valley State University)

help site-fact sheet:

A Homeowner's Guide to Septic Systems (American Environmental Protection Agency)


Open Directory Project (human-edited internet directory) site on wastewater:

Stockholm Environment Institute - Ecological Sanitation Research: Sustainable Sanitation for the developing world; not open source but most publications are free of charge and worth reading

From the fund of the University of Natural Resources and Applied Life Sciences (BOKU), Vienna