60% of a household’s wastewater is graywater. Averaging 90-110 gallons/day
Oregon State Graywater Regulations
Graywater for internal reuse was legalized in 2008 and for external reuse in 2012. DEQ’s webpage on how to get a permitted graywater system, has everything you need to know about the permitting process and recommendations for construction.
Tier 1 permit costs $50 for application fee + $40 annual compiance fee –fee waived if you renew online).
Includes <300 gallons per day of graywater used for
•Subsurface (2″) irrigation of gardens, lawns, and landscape plants, green roofs, compost, food crops (except root crops or crops that have edible portions that contact graywater)
• Subsurface (2″) drip into soil, mulch or compost
• Graywater must be used within 24 hours
• Graywater must not surface, pond, or runoff.
*Graywater can be used year round in a greenhouse.
Tier 2 costs $534 for new application fee + $50 annual fee. Tier 2 is for systems expecting less than 1,200 gallons per day and graywater can be used for drip irrigation, ponds, or year round subsurface irrigation for a greenhouse.
Tier 3 permit fees depend on the project and are designed for over 1,200 gallons per day or reusing graywater for sprinklers or dust control. They’re expected to range from $545 – $2,723 for new application fee. Annual fees may range from $341 -817. Tier 3 permitted graywater systems can treat the graywater of multiple households. If 30 households shared a graywater system that cost $1,500 to be permitted, the cost per household for the permit would be $50 per household, the same as a Tier 1 application fee. The annual renewal costs for 20 households to share a Tier 3 system (imagining their annual fee was on the high end– $800) would be $40/household, equivalent of the Tier 1 annual fee. Recode encourages communities to think creatively about how to reuse their graywater. Imagine a shared treatment system for a neighborhood block that connects to one treatment system that nourishes a neighborhood greenhouse, pond and shared cistern for watering individual gardens.
To find out about Recode’s involvement in the legalization of external graywater reuse see Recode’s Successes.
Arizona State Gray Water Regulations
Arizona legalized graywater reuse eleven years before Oregon, in 2001. Arizona defines graywater as “wastewater collected separately from a sewage flow that originates from a clothes washer, bathtub, shower, and sink, but does not include wastewater from a kitchen sink, dishwasher, or toilet. Note that Oregon uses the term “graywater” and Arizona uses “gray water” with two words. This can make legal research on the reuse of graywater rather tricky.
California based Graywater Installer & Publisher: Art Ludwig
Oasis Designs is a family owned, home-based design consulting and publishing business. They’ve been developing original designs for living better, cheaper, & more ecologically since 1980. A great resource for case studies, regulatory issues and common graywater mistakes.
San Francisco’s Graywater Design Manual by Laura Allen
San Francisco’s Public Utility Commission hired Graywater Action’s Laura Allen (formerly Graywater Guerilla Girls) to create a easy to read design manual with images for homeowner’s creating graywater reuse systems for landscape irrigation.