Summary of Oregon's Water Reuse Guideline or Regulation for 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 Treated Municipal Wastewater.
On this page:
- Technical basis
- Types of planned potable reuse approved for use in Oregon
- Water reuse treatment category type
- Additional context and definitions
- Potable reuse specifications (table)
- Upcoming state law or policy
- References
- Disclaimer
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, potable water reuse The use of highly treated recycled water for drinking water purposes. This reuse application includes both indirect potable reuse through introduction of recycled water into an environmental buffer such as a surface reservoir or groundwater aquifer, and direct potable reuse through introduction of recycled water into a drinking water system. applications include direct potable reuse and indirect potable reuse (groundwater recharge). The source of water treated municipal wastewater Treated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. is specified by the state as domestic wastewater. 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
Potable water in the United States must meet all applicable Safe Drinking Water Act (SDWA) requirements, including its implementing regulations (40 C.F.R. § 141) for chemical and microbial contaminants. Oregon approves the use of recycled water for direct potable reuse (on a case-by-case basis) and indirect potable reuse (IPR) through groundwater recharge which requires, at minimum, a National Pollutant Discharge Elimination Systems (NPDES) permit (40 C.F.R. § 122) or a Water Pollution Control Facilities (WPCF) permit and a “Recycled Water Use Plan” (Or. Admin. R. 340-055). Permitting for groundwater recharge must also satisfy the water quality requirements of the Recycled Water Rules (Or. Admin. R. 340-055) and Groundwater Rules (Or. Admin. R. 340-040). Direct injection of recycled water into a subsurface aquifer is currently prohibited in Oregon. However, subsurface injection of recycled water into the vadose zone is allowed with an Underground Injection Control permit (Or. Admin. R. 340-044).
IPR through groundwater recharge requires Class A recycled water with additional restrictions based on the water quality of the receiving aquifer (Or. Admin. R. 340-055). Class A recycled water has a total coliform requirement and a turbidity requirement (see table, Summary of Oregon’s Potable Reuse Specifications). The technical basis for the derivation of turbidity and total coliform removals are not explicitly specified.
Direct potable reuse of recycled water is authorized on a case-by-case basis and requires Class A recycled water with additional treatment. The additional treatment method and process must be approved in writing by the Oregon Department of Human Services/Health Authority, opened for public hearing and authorized by the Environmental Quality Commission. At this time there is only one facility in Oregon that has met these requirements.
Types of planned potable reuse approved for use in Oregon
Or. Admin. R. 340-055 defines the following approved planned potable uses:
- Indirect potable reuse
- Groundwater recharge, including surface infiltration and subsurface injection (Class A)
- Direct potable reuse (Class A with additional treatment as authorized on a case-by-case basis)
Water reuse treatment category/type
All classes of recycled water must be oxidized and disinfected. Class A recycled water must also be filtered and achieve a turbidity of ≤2 NTU (7-day median) and ≤10 NTU (single sample maximum) and a total coliform concentration of ≤2.2 organisms/100 mL (7-day median) and ≤23 organisms/100 mL (single sample maximum).
Additional context and definitions
Oregon defines groundwater recharge as “the process of adding water to an aquifer for the purpose of restoring and managing groundwater resources. The groundwater may or may not be withdrawn downstream from the injection location.” (Or. Admin. R. 340-055).
Potable reuse specifications
Summary of Oregon's Potable Reuse Specifications
| Recycled Water Class/Category | Source Water Type | Water Quality Parameter | Specification | Sampling/Monitoring Requirements (Frequency of monitoring; site/ location of sample; quantification methods) |
|---|---|---|---|---|
|
Class A |
Domestic wastewater |
Turbidity |
2 NTU (24-hr mean) 5 NTU (5% of time during a 24-hr period) 10 NTU (single sample maximum) |
Hourly; must meet the requirements prior to reaching the aquifer |
|
Total coliform |
2.2 organisms/100 mL (7-day median) 23 organisms/100 mL (single sample maximum) |
Daily; must meet the requirements prior to reaching the aquifer |
Sources = Or. Admin. R. 340-055
Upcoming state law or policy
No upcoming potable reuse regulations were noted for Oregon.
References:
Construction and Use of Waste Disposal Wells or Other Underground Injection Activities (Underground Injection Control), Or. Admin. R. 340-044.
EPA-Administered Permit Programs: The National Pollutant Discharge Elimination System, 40 C.F.R. § 122.
Groundwater Quality Protection, Or. Admin. R. 340-040.
National Primary Drinking Water Regulations, 40 C.F.R. § 141.
Recycled Water Use, Or. Admin. R. 340-055.
Please contact us at [email protected] 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.