The Greywater Guerrillas
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Other Projects

Direct Greywater:

Outdoor pedal-powered washer in Oakland, CA.

How to do drip irrigation with greywater.

Constructed Wetlands:

Desert pond -- greywater passed through three wetlands, in Austin, TX.

Bathtub wetlands -- to treat shower water, in Oakland, CA.

Kitchen sink wetland -- to treat a kitchen sink, in Los Angeles, CA.

Shower water -- another shower system in Seattle, WA with a surge tank.

Composting Toilets:

The prettiest composting toilet in Oakland, CA.

Rainwater Harvesting:

Shower Greywater and Wetland

Constructed 2001 in Seattle, WA 

  • Goals: To use wetland plants to clean and filter shower water for a small vegetable garden. 
  • Site description: A rental house with five residents, two of which use the greywater shower regularly. The shower pipes are fully accessible below the bathroom in an open basement. 
  • Fixtures and output: Shower/bath- about 100 gallons a week.
  • Cost:  Most materials were salvaged- $100
  • Designer: Greywater Guerrillas

Water flow:

1. From bathtub, through P-trap. 

2. To two 2-way diversion valves in basement, which  send it to sewer or surge tank. Note: 2-way diversion  valves could be replaced by one 3-way valve 

3. Out basement wall to surge tank made from one half of a 55-gallon plastic barrel.


4. To sand filter made from other half of barrel filled with sand to 1” below outflow pipe. The sand filter is not necessary, but was added experimentally.


5. To infiltrator basket in constructed wetland.  Infiltrator is made from milk crate wrapped in 1/4”  wire mesh, and prevents plant roots clogging inflow  pipe. Tub drain is sealed with caulked tub stopper. 

6. Through bathtub reedbed filled with 1/2” pea gravel and planted with cattails and irises. 

7. Out  screened overflow drain to garden hose, which is  moved around the garden.

king street system

king street residents
  • Specifications and Notes: In the rainy winter the system is turned back to the sewer. The 2, two valves could be replaced by one three way valve.  The wetland transpires some of the greywater as the small yard does not need much irrigation. 
  • Maintenance and trouble shooting:  The sand  in sand prefilter needs to be changed annually. Sand filters are typically used to filter microbes and sediment out of drinking water and can be used to clarify greywater after wetland treatment. The sand prefilter in this system was an experiment, and is probably superfluous as the wetland provides adequate filtration for surface irrigation through a garden hose.  The greywater hoses are moved around the garden.