Oregon's Greywater Rules at a Glance
Oregon's greywater regulations are codified in OAR 918-750 and sit under the state's plumbing specialty code. Unlike Texas or Arizona, there is no no-permit exemption for laundry-to-landscape systems in Oregon — every residential greywater installation requires a plumbing permit from the Oregon Building Codes Division or from a local municipality that has adopted the specialty code. This is enforced primarily through the plumbing permit system rather than environmental health departments.
The core framework allows greywater to be used for subsurface landscape irrigation (the same use as in other states), but the permit requirement adds an overhead step and typically involves a licensed plumber pulling the permit. Homeowner-pulled permits are technically allowed in Oregon for work on owner-occupied single-family dwellings, but not all local authorities accept homeowner permits for greywater systems — verify locally.
What Is NSF/ANSI Standard 41?
NSF/ANSI Standard 41 is a certification standard for "Non-Liquid Saturated Treatment Systems" — essentially any device that treats or conveys greywater before it reaches the soil. Oregon's rules require that components used in permitted greywater systems (particularly treatment devices and some distribution components) be tested and certified to this standard.
In practice, this matters most for:
- Surge tanks or storage containers: Any tank used to hold greywater before distribution must be listed to NSF 41 or be a properly rated plumbing product
- Treatment filters: If your system includes a filter or treatment step, it must be NSF 41 certified
- Diverter valves: Standard three-way diverter valves from recognized irrigation suppliers generally meet the applicable standards — verify the specific product with your permit reviewer
For a simple L2L system with no storage tank and no treatment step, NSF 41 primarily affects component selection. Most quality irrigation-grade diverter valves and poly tubing products are acceptable — your permit reviewer will confirm specific product requirements.
Portland and Multnomah County
Portland operates under the Oregon Specialty Codes and processes greywater plumbing permits through the Portland Bureau of Development Services (BDS). Portland has been relatively supportive of greywater installations as part of its water conservation and green building goals.
Portland permit process for a simple residential L2L system:
- Submit a Plumbing Permit application through Portland's PermitPortland online system
- Provide a site plan showing washing machine location, pipe routing, and landscape discharge areas
- Permit fee: typically $150–$250 for residential plumbing permits covering greywater work
- Review: 2–4 weeks for standard applications
- Inspection: required before the system is put into service
Portland's BDS staff have reviewed greywater permits before and can answer specific questions about component requirements — contact BDS's residential plumbing team directly.
Rural Oregon and Smaller Counties
Outside Portland and the Willamette Valley's urban centers, greywater permits are processed by local building departments or, in some areas, the Oregon BCD directly. Rural counties in Eastern Oregon (Malheur, Harney, Lake) have minimal experience with greywater permits — applications may require some education of local staff. The Oregon BCD's technical assistance line (503-378-4133) can help navigate local processes.
On-lot septic systems (common in rural Oregon) affect the overflow connection requirement — your system must overflow to your septic, not to a surface ditch. Consult your septic installer before designing the overflow path.
What Oregon Allows
Under a valid permit, Oregon allows:
- Laundry-to-landscape irrigation with mulch basin discharge
- Shower and bath water systems (with surge tank, more complex permit)
- Drip, bubbler, and subsurface distribution methods
- Irrigation of ornamental plants, turf, shrubs, and trees
Oregon does not allow (even under permit): edible crop irrigation with greywater, spray application, surface ponding, or any discharge to stormwater systems.
Frequently Asked Questions — Oregon
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Oregon allows homeowners to pull plumbing permits for their own owner-occupied single-family homes under the homeowner exemption. However, the work must still pass inspection. If the inspector finds that the installation doesn't meet Oregon's specialty code requirements, you'll need to correct it before approval. Many Oregon homeowners successfully self-install simple L2L systems under homeowner permits — but for more complex systems (Tier 2, multiple sources), a licensed plumber is strongly advisable.
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Western Oregon gets 36–60 inches of rain annually, so active landscape irrigation is only needed from about June through October — roughly 5 months. During that dry period, greywater can meaningfully reduce potable water use. Eastern Oregon is much drier (10–15 inches annually) and greywater is more consistently valuable there. Many Portland homeowners use L2L systems 5–6 months per year and redirect to sewer November–May, which is a reasonable and practical approach.
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Plumbing permit fees in Oregon vary by jurisdiction. Portland charges based on the value of the work — a simple L2L installation is typically valued at $300–$800 in labor and materials, resulting in a permit fee of $150–$200. Smaller jurisdictions may use a flat fee of $75–$150. Contact your local building department for current fee schedules.