Summary of Oregon's Water Reuse Guideline or Regulation for Agriculture

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
• Water reuse for agriculture approved for use in Oregon
• Water reuse treatment category for agriculture
• Additional context and definitions
• Water reuse for agriculture 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, water reuse for agriculture water reuse for agricultureThe use of recycled water to land to assist in the production of both commercially and non-commercially processed food crops consumed by humans or livestock and non-food crops. Includes pasture for milking and non-milking animals, fodder, fiber, and seed crops, vineyards, orchards, ornamental nursery stock, Christmas trees, and silviculture. Excludes consumption by livestock, onsite non-potable reuse, and landscaping. includes any agricultural or horticultural use; orchards or vineyards if an irrigation method is used to apply recycled water directly to the soil; processed food crops; pasture for animals; sod; firewoods, ornamental nursery stock and Christmas trees; commercial timber; and fodder, fiber and seed crops not intended for human ingestion. The source of water (treated municipal wastewater) 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. This 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 reuse of recycled water for agricultural irrigation, including irrigation of crops not intended for human ingestion, processed food crops, ornamental nursery stock, sod, pasture for animals and orchards or vineyards (Or. Admin. R. 340-055). All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met. Additionally, commercial food crop growing operations may be subject to any relevant rule requirements under the Food Safety Modernization Act (FSMA) (124 Stat. 3885). Public access requirements designed to minimize exposure to recycled water are specified for each class of water (Or. Admin. R. 340-055). Any recycled water use in Oregon requires, at minimum, a National Pollutant Discharge Elimination System (NPDES) permit (40 CFR 122) or a Water Pollution Control Facilities (WPCF) permit and a “Recycled Water Use Plan” (Or. Admin. R. 340-055). Treatment requirements and performance standards are applied for the removal of microbial contaminants and other relevant indicators related to agriculture and are summarized in the table. The technical basis for the derivation of turbidity, total coliform and E. coli removals for Class A, B and C recycled waters is California’s Title 22 Water Recycling Criteria (Cal. Code Regs. tit. 22). The E. coli removals for Class D recycled water are based on the values from Oregon’s freshwater contact from recreational activities (Or. Admin. R.  340-041-0009).

Water reuse for agriculture approved for use in Oregon

Or. Admin. R. 340-055 defines the following approved water reuse for agriculture:

• Any agricultural or horticultural use (Class A)
• Orchards or vineyards if an irrigation method is used to apply recycled water directly to the soil (Class C)
• Processed food crops (Class C)
• Pasture for animals (Class D)
• Sod (Class D)
• Firewood, ornamental nursery stock, Christmas trees (Class D)
• Commercial timber (Class D)
• Fodder, fiber, seed crops not intended for human ingestion (nondisinfected)

Water reuse treatment category for agriculture

All classes of recycled water must be oxidized and disinfected (Or. Admin. R. 340-055). The classes are differentiated by their specific treatment requirements, turbidity and total coliform requirements:

• 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).
• Class B recycled water must achieve a total coliform concentration of ≤2.2 organisms/100 mL (7-day median) and ≤23 organisms/100 mL (single sample maximum). 
• Class C recycled water must achieve a total coliform concentration of ≤23 organisms/100 mL (7-day median) and ≤240 organisms/100 mL (single sample maximum).
• Class D recycled water must achieve an E. coli concentration of ≤126 MPN (30-day log mean) and ≤406 MPN (single sample maximum).

Oregon also allows permitted facilities to use nondisinfected recycled water for reuse applications including those related to agriculture. Public access to the irrigation site must be prevented. Irrigation with recycled water is prohibited for 30 days before harvesting. Sprinkler irrigation is prohibited unless authorized in advance and in writing by the department based on demonstration that public health and the environment will be adequately protected from aerosols. The state cautions that nondisinfected water should be assumed to contain significant levels of pathogenic organisms and carry the highest public health risk (Oregon DEQ 2009). Oregon encourages facilities currently permitted to reuse nondisinfected water to treat their effluent to Class D or better for agricultural irrigation (Oregon DEQ 2009). 

Additional context and definitions

Land application of recycled water requires notification and may require registration with the Oregon Department of Water Resources (Or. Admin. R. 537.132; Or. Admin. R. 340.055.0017). Oregon defines recycled water as “any treated effluent from a domestic wastewater treatment system that (as a result of treatment) is suitable for a direct beneficial purpose” (Or. Admin. R. 340-055). 

Oregon provides specific site management practices for each class of water. Most practices relate to signage requirements or harvesting/irrigation restrictions (Or. Admin. R. 340-055).

Oregon requires municipal recycled water to be distributed through pipes that are appropriately identified by color (i.e., “purple pipe”) and labelled (Or. Admin. R. 340-055). Cross connections between a potable water supply and recycled water distribution system are not allowed unless the connection is through an air gap separation approved by Oregon DEQ. Oregon’s Recycled Water Use Rules also require signage to mark recycled water to prevent cross-connections. Signs must be in English and Spanish and contain language indicating recycled water is used and not safe for drinking, for example, “RECYCLED WATER USED – NOT SAFE FOR DRINKING” (Oregon DEQ 2009). The recycled water generator must actively notify any person that may come into direct contact with recycled water (ex. employees) for all classes of recycled water and for all end uses. 

Water reuse for agriculture specifications

Oregon DEQ provides a list of approved analytical methods for bacterial and turbidity testing in Table 10 of their Recycled Water Use Rules (Oregon DEQ 2009).

Summary of Oregon's Water Reuse for Agriculture Specifications

Source= Or. Admin. R. 340-055; Oregon DEQ 2009

* 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.

^a Or. Admin. R. 340-055 specifies the frequency of bacteria and turbidity monitoring required for each recycled water Class. These requirements are also described in Oregon DEQ (2009). “For bacteria monitoring, the rule specifies a frequency of daily, 3- times/week, or weekly and includes acceptance criteria such as a “30-day log mean” (Class D) or median value “based upon the last seven days” (Classes A, B and C). The seven day median value is intended to be made from the last seven consecutive samples that are representative of the treatment process and operating conditions. The seven consecutive samples do not need to be collected on seven consecutive days. However, collecting seven samples on a single day is not acceptable, nor is selectively choosing seven previous samples out of a larger number. When samples are collected more frequently than specified in the rule (e.g., following an upset in the treatment system or during startup), those should be used in the calculation. For other monitoring parameters, the monitoring frequency should be sufficient to reasonably characterize the recycled water stream” (Oregon DEQ 2009). 

^b “Analytical testing methods for determining compliance with federal and state water quality standards must comply with 40 CFR Part 136, or if Part 136 does not prescribe a method, then with the most recent addition of Standard Methods for the Examination of Water and Waste Water published jointly by the American Public Health Association, American Water Works Association and Water Pollution Control Federation [OAR 340-041-0061(14)]” (Oregon DEQ 2009).

^c Specific nephelometric methods include ASTM D1889- 94,00, USGS I-3860-85, EPA Method 180.1 Rev 2.0 (1993), Standard Method 2130 B, or Standard Method Online 2130 B-01 (Oregon DEQ 2009; Table 10).

^d Specific methods include standard methods 9222 D and 9222 D-97 and EPA (1978) for single step membrane filtration; standard methods 9222 B and 9222 B-97, USGS B-0025-8 and EPA (1978) for single step or two step membrane filtration; and standard methods 9221 B and 9221 B-99 and EPA (1978) for most probable number (5 tube, 3 dilution) (Oregon DEQ 2009; Table 10).
 

Upcoming state law or policy

No upcoming regulations pertaining to water reuse for agriculture were found for Oregon.

References

Bacteria, Or. Admin. R. 340-041-0009.

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

EPA-Administered Permit Programs: The National Pollutant Discharge Elimination System (NPDES), 40 C.F.R. § 122.

Rules, Or. Admin. R. 537.132(2).

Food Safety Modernization Act (FSMA), 124 Stat. 3885.

Oregon Department of Environmental Quality (DEQ). 2009. Implementing Oregon’s Recycled Water Use Rules.

Recycled Water Use, Or. Admin. R. 340-055.

Treatment and Use of Recycled Water, Or. Admin. R. 340.055.0017.

USEPA. 1978. Microbiological Methods for Monitoring the Environment, Water, and Wastes. Environmental Monitoring and Support Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH EPA/600/8-78-017.

Water Recycling Criteria, Cal. Code Regs. tit. 22.

---

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.