The Greywater Guerrillas
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Other Projects

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Branched Drain to Bamboo in Berkeley, CA.

Washing machine to large yard in Arcata, CA

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How to do drip irrigation with greywater.

Constructed Wetlands:

Tiered wetland -- greywater passed through three wetlands, in Austin, TX.

Small wetland to filter shower and grow cattails for use in Oakland, CA

Pretty wetland and wash water in Oakland CA

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

Kitchen sink water garden -- 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.

Elevated indoor composting toilet in Oakland, CA

Rainwater Harvesting:

Drumless Laundry- Multiple Irrigation Zones

Constructed 2007 in Oakland, CA

  • Goals: To reduce fresh water use and to grow fruit trees.
  • Site description: The washing machine is in the basement, about two feet below ground level. The yard is large and sloping away from the house. The soil is clayey with slow drainage. 
  • Fixtures and output: One washing machine, front loading. 10 gallons/load- about 8 loads a week.
  • Cost: $200 for parts. 

Water flow:

Water from the washing machine is connected to a Jandy 1.5 inch  3-way valve: one direction goes to the laundy sink which ends up in the sewer, the other goes outside to the trees. An 1.5"  to 1" bushing is used to reduce the 3-way valve down to fit the 1" pipe. (note: a 1" brass 3-way ball valve could also have been used in this system).

washer

The water travels in 1" PVC pipe. This size is small enough to keep the water pressurized from the washing machine's internal pump,  but not too small as to put too much friction on the pump. The pipe leaves the house in a small hole drilled with a hole saw.

water out

Once outside the pipe is vented with an "air gap" to prevent accidental siphoning of the washing machine when it tries to fill up. This air gap leaks a little water at the start of each wash cycle, which conveniently waters a plant growing next to it. If no leakage is desired use an "auto vent" instead.  A "check valve" was included in line to prevent the possibility of water back flowinng into the machine. In this situation it's not likely to happen since the greywater flows with gravity through the rest of the system. If the pipe was a flexible hose and it was lifted, then water could flow back into the machine if there was not a check valve.  Check valves are available in PVC or brass.

air gap and check valve

The pipe flows to a "manifold" where the greywater is split into three lines. Two lines go to fruit trees and the third goes to a flexible hose.

into manifold
In the manifold the greywater lines are controlled by "ball valves" that can be shut on or off. Ball valves are available in plastic or metal. Often the 1" plastic valves are very hard to open and close, while the brass ones are easy. In this system it's crucial that one valve is always open, if they all were shut accidentally  the water would have no where to go and it could burn out the pump. The owners alternate between the two greywater lines to allow the soil to dry out, as well as to extent the number of trees the greywater can reach. After each ball valve there is a "union" that can be opened if the line ever clogged. manifold
The pipes leave the manifold and travel in a trench to the fruit trees. This picture is during construction; after it was built all the pipes were buried.pipes leaving manifold
One line of greywater splits to water three fruit trees (not all are planted in this picture). The greywater is infiltrated into large mulch basins. A 6 foot circle was dug out around a mound where the tree was planted. The 18 inch deep ring around the tree was filled with mulch. This allows the greywater to spread out and sink into the ground slowly. The white buckets have no bottom and lots of holes in them allowing the greywater to flow out, but keep mulch from getting into the pipe. The greywater falls a few inches onto the mulch, preventing clogging. to trees
A close up of a split shows a tee dividing the flow into two parts, one to the tree and the other down the line to the next tree. The pipe extention going out from this tee to the fruit tree can be removed when the tree grows larger, thus creating more distance from the greywater irrigation point and the tree trunk.  Trees need to be watered close to the trunk when young, and farther away as they grow to encourage the roots to extend outwards.branch
The basins are filled with mulched tree bark and the bucket infiltrators are covered with stepping stones. The stone can be lifted to view the greywater pipe. fruit tree
  • Specifications and Notes: Before any of the pipes were burried several trial runs were conducted. At first the greywater came out unevenly amoung the infiltrator buckets. After readjusting the slope of the pipes, raising some, lowering others, the water flowed evenly to all areas. Then the pipes were burried. 
  • Maintenance and trouble shooting: The ball valves need to be switched to alternate between greywater lines. The third line is a flexible hose and it is moved to a few plants that need occasional watering. In times of heavy rains the system has been switched to the sewer since the soil is so clayey. Eventually new mulch will need to be added to the mulch basins.