Oregon Greywater Code

Oregon is currently preparing a new greywater code.

The proposed rules are available for public comment until March 11, 2011

This is a long and complex document, but in summary, it defines 3 tiers of Greywater Reuse.

Tier 1 will apply to most single-family residences mot exceeding 300 gallons per day of greywater.

Subsurface irrigation is required (the greywater outlet must be covered by 2″ of soil or mulch).

A permit is required for all Tiers. The least expensive is Tier 1, requiring an annual registration fee of $50. This Tier requires a simple registration and does not require lot maps, plans or inspections.

This page will be updated when the public comment period has closed, and the Oregon DEQ produces a finalized code. Although the requirement for an annual registration fee is disappointing, the overall code is sensible and allows for technological innovation. I congratulate both the Advisory Committee and the DEQ on their efforts and outcome.

Oregon DEQ plans to recommend that the Oregon Environmental Quality Commission adopted the rules at the commission’s August 2011 meeting.

An advisory committee was appointed by the Oregon DEQ and produced a final report in November 2010.

Recommendations on Greywater Treatment, Disposal and Reuse

As the report is 26 pages (!) long, I am only listing the most interesting sections on this page.

Untreated Graywater.

The committee recognizes that the use of untreated graywater carries potential hazards to public health and has developed specific recommendations to address these concerns. Direct contact with untreated graywater by humans and domestic pets should be minimized. When used for irrigation, the edible portion of crops should not contact the graywater.

Untreated graywater should only be used for subsurface irrigation and composting. Untreated graywater may not be stored for more than 24 hours and, when used for irrigation, must be released under at least two inches of soil, mulch or other covers. Buffers or horizontal setback distances should be maintained from surface waters, stormwater systems, and property lines. Because of potentially high concentrations of organic material, solids and bacteria, all graywater originating from kitchen sinks should pass through a system designed to reduce grease, floatable solids, and settleable solids.

Treated Graywater.

The committee also recognizes that with appropriate treatment, graywater may be safely used for other uses, such as surface irrigation and landscape ponds. The committee recommends that graywater treatment systems either (1) use a technology‐based system recognized by an accreditation authority such as the American National Standards Institute or (2) meet performance-based criteria of an effluent concentration not to exceed 10 milligrams per liter for both five‐day Biochemical Oxygen Demand (BOD5) and total suspended solids (TSS). With disinfection, graywater may be safely used for additional applications, such as spray irrigation, wash water, and various construction uses. Graywater disinfection standards should be consistent with Oregon’s definition for Class B recycled water, which is a total coliform concentration not to exceed a seven‐day mean of 2.2 colony‐forming units (CFU)/100 mL under a three‐day/week monitoring frequency. Graywater treatment systems should be subject to monitoring and reporting requirements to show they comply with these standards.

Graywater Permits.

Finally, the committee recommends that the EQC adopt a tiered approach to graywater permitting that is primarily based upon the volume of graywater produced. This tiered approach should allow low‐volume residential graywater systems, which represent a low threat to public health or the environment, to be permitted with minimal effort, while high‐volume, complex systems should be subject to the appropriate review and approval.

  • Tier 1 General Permit. A Tier 1 general permit should be available for a single‐family residence or duplex that generates less than 300 gallons per day (gpd) of graywater that will be used only for subsurface irrigation. If the system meets certain eligibility requirements, the permit can be obtained by registering the system with DEQ and paying a small fee.
  • Tier 2 General Permit. A Tier 2 permit should be available for a single‐ or multi‐family residence, institution, commercial facility or industrial facility employing a graywater treatment system and producing less than 300 gpd for uses other than subsurface irrigation as well as any graywater system producing between 300 and 1,200 gpd. Because these types of systems represent a higher risk to public health and the environment, the permit should be obtained only after paying a fee and submitting documentation on system design and operation to DEQ for review and approval.
  • Tier 3 Individual Permit. Any graywater system producing greater than 1,200 gpd should be allowed under an individual Tier 3 permit. Moreover, any low‐ or medium‐volume graywater system that fails to qualify for a Tier 1 or Tier 2 permit can apply for an individual permit. The committee further recommends that graywater disposal options be considered by DEQ under an individual Tier 3 permit. Because of the volume, potential complexity, site limitations or other conditions, these types of graywater systems may require careful review of system design, maintenance, and operation. The fee for a Tier 3 permit should be appropriately scaled to the amount of effort required to develop the permit and the volume of graywater produced.

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