Greywater for Sinks and Showers

Do’s and Don’ts of Greywater for Showers and Sinks:


  • Label: Greywater pipes need to be clearly labeled, expecially PVC pipes, to differentiate them from potable water pipes.

  • Build it Big: Oversizing your system allows for the unexpected. A sudden surge in water use can be contained in an oversized sytem.


  • Drink: Greywater is not safe to drink or wash with.

  • Root Vegetables: Do not allow greywater to come into contact with edible portions of food crops.

  • Spray: Do not distribute greywater through sprinklers.

  • Hang on to it: Greywater cannot be stored safely for more than 24 hours. Don't try to store it until summer, you will have Blackwater (septic) water in your tank, not Greywater.

How to Size Irrigation for Showers and Sinks:

  • Find the flow rates of faucets, shower heads, and washing machines:

  • Calculate your shower head or faucet flow, open the shower/faucet on full blast. Capture water in a container for 60 seconds. Pour that water into a one gallon container to measure how much came out in one minute to calculate the GPM (gallons per minute) of your fixture.