Summary of Oregon’s Water Reuse Guideline or Regulation for Landscaping and Onsite Non-potable Water Reuse

This page is part of the EPA’s REUSExplorer tool, which summarizes the different state level regulations or guidelines for water reuse for a variety of sources and end-uses.
The source water for this summary is Rainwater Collected Onsite.

On this page:

• Technical basis
• Onsite non-potable water reuse applications approved for use in Oregon
• Water reuse treatment category/type
• Additional context and definitions
• Onsite non-potable water reuse specifications (table)
• Upcoming state law or policy
• References
• Disclaimer

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This page is a summary of the state’s water reuse law or policy and is provided for informational purposes only. Please always refer to the state for the most accurate and updated information. 

In Oregon, landscaping water reuse for landscapingThe use of recycled water on land to assist in the irrigation of vegetation in residential and non-residential areas. Includes impoundments to store water for irrigation , ornamental vegetation, parks, school yards, sporting facilities (including golf courses), private gardens, roadsides and greenbelts, and cemeteries. Excludes irrigation of areas used for agriculture, commercial reuse applications, or any centralized non-potable reuse. reuse applications include irrigation and onsite non-potable water reuse applications include water closets, urinals, tap primers, clothes washers, cooling tower makeup and water features. The source of water (rainwater collected onsite) rainwater collected onsite Precipitation collected at the district or regional scale is classified separately under 'stormwater.' is specified by the state as rainwater. The write-up uses state terms when discussing sources or uses of water that may differ from the Regulations and End-Use Specifications Explorer's (REUSExplorer's) terms.

Technical basis

Oregon approves the use of both above and below ground rainwater catchment systems for onsite non-potable water reuse applications, including use in water closets, urinals, tap primers for floor drains and floor sinks, clothes washers, irrigation, water features and cooling tower makeup (OPSC, 2021). Non-potable rainwater catchment systems must be designed in accordance with the Oregon State Plumbing Code (OSPC) by a registered design professional. All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met in addition to any state water quality standards. A permit is required for the construction, installation, repair or alteration of non-potable rainwater catchment systems, except if the reuse is limited to outdoor applications and/or the entirety of the catchment system is in the exterior of the building (OPSC, 2021). Treatment requirements and performance standards are applied for the removal of microbial contaminants and other relevant indicators related to onsite non-potable water reuse and are summarized in the onsite non-potable water reuse specifications table. The technical basis for developing the specifications and/or removal of microbial contaminants and other relevant indicators is not explicitly specified.

Onsite non-potable water reuse applications approved for use in Oregon

The Oregon State Plumbing Code (2021) defines the following specific onsite non-potable water reuse applications for rainwater catchment systems:

• Water closets
• Urinals
• Tap primers for floor drains and floor sinks
• Clothes washers
• Irrigation
• Water features
• Cooling tower makeup

Additional onsite non-potable water reuse applications for rainwater are not specified.

Water reuse treatment category/type

Oregon does not assign harvested rainwater used for onsite non-potable water reuse to a category or class but does provide specific minimum water quality requirements based on intended application. Water treatment is not required for the following exceptions (OPSC, 2021):

• Rainwater catchment systems used for aboveground irrigation with a maximum storage capacity of less than 360 gallons.
• Rainwater used for subsurface or non-sprinkled surface irrigation where maximum storage capacity is less than 360 gallons.

Specific treatment requirements are provided for harvested rainwater. Briefly, these treatment requirements include:

• Filtration: All rainwater catchment systems must include a debris excluder or other approved means to prevent accumulation of leaves, needles, sediment and other debris from entering the storage tanks (OPSC, 2021). Collected rainwater must be further filtered as required for the intended end use. Specifically, non-potable water utilized for water closets, urinals, tap primers and drip irrigation systems must be filtered by a 100-micron or finer filter (OPSC, 2021). All filtration systems must have a mechanism to indicate servicing or replacement as well as be installed with shutoff valve immediately upstream and downstream to allow for maintenance (OPSC, 2021).
• Disinfection: Oregon requires harvested rainwater to be disinfected as necessary to meet water quality requirements specific for the intended onsite water reuse application, including those provided in the onsite non-potable water reuse specifications table (OPSC, 2021).

Additional context and definitions

Oregon provides specific requirements on the collection, distribution and drainage materials of rainwater catchment systems. In Oregon, collection of rainwater is limited to above-ground impervious surfaces (OPSC, 2021). Water supply and distribution materials utilized in rainwater catchment systems per ORS statute 537.141 (1)(h) and (6) must be constructed of similar and approved materials (OPSC, 2021; ORS, 2023).

Oregon requires specific design elements when implementing rainwater catchment systems. Rainwater catchment systems must be compatible with the pipe and fitting materials, water treatment and water conditions (OPSC, 2021). Rainwater storage tanks must be constructed of solid, durable, water-tight materials not subject to excessive corrosion or decay (OPSC, 2021). All components of the storage tanks must be designed with room for cleanout and inspection (OPSC, 2021). Oregon allows for both above and below grade non-potable water storage tanks, given an approved permit, under the requirements summarized in the OPSC (2021).

All non-potable water storage tanks must be made identifiable with signage with the words “CAUTION: NONPOTABLE RAINWATER, DO NOT DRINK” (OPSC, 2021). Commercial and institutional restrooms using nonpotable rainwater for water closets or urinals require signage made visible to users with the words “TO CONSERVE WATER, THIS BUILDING USES RAINWATER TO FLUSH TOILETS AND URINALS” (OPSC, 2021). Equipment rooms containing non-potable rainwater equipment must have a sign posted with the words “CAUTION NONPOTABLE RAINWATER DO NOT DRINK. DO NOT CONNECT TO DRINKING WATER SYSTEM. NOTICE: CONTACT BUILDING MANAGEMENT BEFORE PERFORMING ANY WORK ON THIS WATER SYSTEM” (OPSC, 2021).

Onsite non-potable water reuse specifications

Summary of Oregon's Onsite Non-potable Water Reuse Specifications

Sources = OPSC (2021)

* Information about sampling and monitoring requirements such as frequency, site and quantification methods not specifically listed in the table was not explicitly specified in the State-specific regulations.

Upcoming state law or policy

No upcoming onsite non-potable rainwater reuse regulations were found for Oregon. 

References:

Clean Water Act, 33 U.S.C. §§ 1251 et seq.

State of Oregon Plumbing Specialty Code (OPSC). 2021.

Oregon Revised Statutes (ORS). 2023.

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Disclaimers

Please contact us at waterreuse@epa.gov if the information on this page needs updating or if this state is updating or planning to update its laws and policies and we have not included that information on the news page.