Greywater Resources

From SF PowerWaterSewer: Graywater is water from showers, bath tubs, washing machines, and bathroom sinks. It is water that contains some soap but is clean enough to water plants. Water from toilets or wash water from diapers is never considered graywater. [Kitchen sink water is not considered graywater in California, although it is in some other states.]


PRESENTATION from DIY Greywater System workshop, adapted from Greywater Action


GENERAL INFO about water conservation & greywater:


REBATES & INCENTIVES for household greywater:




TIPS for using residential greywater from Greywater Action:


  1. Don’t store greywater (more than 24 hours). If you store greywater, the nutrients in it will start to break down, creating bad odors.
  2. Minimize contact with greywater. Greywater could potentially contain a pathogen if an infected person’s feces got into the water, so your system should be designed for the water to soak into the ground and not be available for people or animals to drink.
  3. Infiltrate greywater into the ground, don’t allow it to pool up or run off (knowing how well water drains into your soil (or the soil percolation rate of your soil) will help with proper design. Pooling greywater can provide  mosquito breeding grounds, as well as a place for human contact with greywater.
  4. Keep your system as simple as possible, avoid pumps, avoid filters that need upkeep. Simple systems last longer, require less maintenance, require less energy and cost less money.
  5. Install a 3-way valve for easy switching between the greywater system and the sewer/septic.
  6. Match the amount of greywater your plants will receive with their irrigation needs.
  7. Recommended washing products: (they are salt and boron free, and pH neutral)
    • Laundry: Oasis, Ecos, Biopac liquid detergent, Vaska. There are also soap alternatives that are greywater-friendly, like soap nuts, and “wonder balls.”
    • Showers: Aubrey Organics makes shampoos and conditioners that don’t have salt or unhealthy chemicals, and are fairly easy to find. [In a shower, shampoo is fairly diluted so it is not as important as in the washing machine to have the best products, but it is important to have products that are not harmful to our health. You can find out what’s in your products at the Campaign for Safe Cosmetics‘s on-line database.]




SUPPLY RESOURCES for greywater installation:

  • Urban Farmer; Locations in San Francisco (Sunset District), Mill Valley, Richmond
  • Home Depot
  • Ace Hardware
  • Ponderosa Tree Service for free mulch!
  • Ewing Irrigation, in San Francisco, San Leandro, and Pacheco [for spears union teeth



quantity :  type, size, material

  • 1 : PVC 1” male pipe thread x 3/4” barb
  • 3 : PVC 1” male adapters
  • 1 : brass three-way valve
  • 1 : PVC 1” T
  • 1 : PVC  1.5” x 1” bushing
  • 1 : PVC 1.5” female adapter
  • 12 : PVC 1” 90° elbow
  • 4 : PVC 1” 90° street elbow
  • 6 : PVC 1” 45° elbow
  • 1 : 1.5” auto vent (anti-siphon valve)
  • 80 feet : 1” PVC pipe [we used 80ft based on the distance from washer to front yard; you may need less]
  • 8 :  ABS drain pipe hangers
  • 2 bags : 1” plastic grey 2-hole conduit straps (electrical dept.)
  • 1 bag : 1.25” plastic grey 2-hole conduit straps (electrical dept.)
  • 1 : .5” roll of Teflon tape
  • 1 : Gorilla PVC glue
  • 6 : small irrigation boxes (reduce or increase number depending on your calculation; can use pipe instead)
  • 1 : medium size irrigation box
  • 1 : small piece of plywood or other thin board to mount three way valve – 20” x 6” would be ideal
  • 1 : PVC 1” insert (spigot) x 1” barb
  • 1 : PVC .5 x. 75 insert x .75 female swivel hose thread
  • 2 : hose clamps that fit around 1” pipe
  • 40 feet : 1” poly tubing (black for blue lock is fine)
  • 6 : PVC 1” x .5” barb T
  • 4 : green back quarter-turn barb ball valve
  • 1 : PVC 1” barb T
  • The union-thing-with-no-name
  • ABS hangers 
  • 2-hole straps in 1” and 1.5′‘  (come in bags of 6) 


On “GREY” versus “GRAY”: Gray and grey are different spellings of the same word, and both are used throughout the English-speaking world. But gray is more common in American English, while grey is more common in all the other main varieties of English. The Grammarist