Graywater

greywater concept sketch

Are you interested in finding a way to reduce the amount of tap water you use to water your landscape or garden? In Oregon, we all have a new way to recycle our water. It’s called Graywater!

Read on to learn more about graywater, how it can be used, and how to obtain a graywater permit in Oregon. You can also contact us if you have any graywater questions or are interested in setting up a system.

What is Graywater?

Graywater is water from washing machines, sinks, showers and bathtubs. It is water that contains some soap, but is clean enough to water plants.

What are the benefits of using gray water?

graywater_chart
Gray water systems can significantly reduce the amount of water you use during the summer to water your garden and landscaping. Approximately thirty percent of residential water use in the US is for outdoor watering. By reusing the water from a washing machine, shower, sink, or bathtub, the average household could reduce its water usage by 16-40%!

Oregon’s Graywater Program

For years it has been legal in Oregon to harvest graywater to be used indoors for toilet flushing. Oregon’s new graywater program (started April 2012) allows us to use graywater for outdoor watering as well.

May be used as a source of
graywater:
Cannot be used as a source of
graywater:
Shower Toilet water or waste
Bath Water from a garbage disposal
Bathroom sink Water from a dishwasher
Kitchen sink Water contaminated by soiled diapers
Washing machine
What can I water in my garden using graywater?

Graywater can be used safely to water lots of plants around your home (using sub-surface irrigation).

  • Fruit trees
  • Berries
  • Vegetable gardens (As long as the graywater does not touch the edible portion of the plant)
  • Lawn areas and landscape plants

See the DEQ website for a more comprehensive list of plants that can be watered using graywater. http://www.deq.state.or.us/wq/reuse/docs/graywater/GraywaterGuideHomeowners.pdf

What should I not water with graywater?
  • Root crops: Bacteria in the graywater could contaminate root vegetables and make someone sick if they eat them.
  • Acid loving plants: Graywater is generally more alkaline than potable water, so some acid loving plants may be damaged by graywater.
  • Drought tolerant plants: Established plants that are used to dry conditions may not respond well to new irrigation.
Getting a Permit for your graywater project

In Oregon, to use graywater for your garden and landscaping, you’ll need to get a few permits before installing the system at your home.

  1. Plumbing permit for the local jurisdiction
  2. Graywater permit from the OR Department of Environmental Quality

For more information on the permitting process, see the OR DEQ Graywater website: http://www.deq.state.or.us/wq/reuse/graywater.htm

Reusing Graywater in Your Landscape: A Guide for Oregon Homeowners:
http://www.deq.state.or.us/wq/reuse/docs/graywater/GraywaterGuideHomeowners.pdf

Questions and Answers: Permits for graywater reuse and disposal systems:
http://www.deq.state.or.us/wq/reuse/docs/graywater/PermitsQA.pdf

Graywater Presentation:
http://www.deq.state.or.us/wq/reuse/docs/graywater/GWgenPublic.pdf

Using Graywater Indoors

For more information on using graywater for toilet and urinal flushing, see the Water Conservation Systems Oregon Smart Guide
http://www.bcd.oregon.gov/pdf/smart_guides.html

Non-potable use of graywater within a structure for toilet and urinal flushing is regulated under the state plumbing code.

Additional Resources
Other states also have good resources and information on graywater systems.

Please note that some of the information from the following websites (permitting, regulations, rainfall patterns, etc.) may not apply to graywater systems in Oregon.