In Oregon, it is currently illegal to use untreated gray water. To treat and use gray water requires a permit which, in most cases, is prohibitively expensive. The Oregon Department of Environmental Quality is in the preliminary stages of considering changes to gray water regulations.
DEQ's graywater fact sheet covers background, basic graywater information, and permitting questions.
Gray water is generally defined as all domestic wastewater except toilet water.
This includes sink, bath, dishwasher, and laundry water and is NOT potable (drinkable). In regions with limited potable water sources, particularly during summer months, there is an increased interest in using gray water for irrigation and other uses that do not require a highly purified source.
Be aware that gray water regulations vary from state to state!
Currently, in Oregon, gray water is classified as sewage and is regulated under OAR 340-071 (Oregon's onsite wastewater treatment system regulations). Treatment and reuse of gray water requires appropriate DEQ permits.
In 2012 DEQ began accepting applications for graywater permits.
There are three tiers of permits (1 general, 2 general, and 3 individual) one can apply for. If you would like more information on obtaining a permit visit DEQ graywater.
For more on water re-use regulations: DEQ Water Re-use Site
Future changes may result in greater flexibility for homeowners to reuse gray water while protecting the health of the community. Keep checking to see if DEQ makes any further changes to graywater use regulations.
Finally, for even more on graywater and recent news, check out the Rainbow Water Coalition.