Oregon – Composting Rules

Oregon’s composting regulations aim to facilitate composting while preventing public nuisance issues and any adverse environmental consequences from materials mismanagement. Described below are Oregon’s conditional exemptions for small-scale and agricultural compost facilities, specific site requirements needed to receive an operating permit, and ongoing performance standards for facilities to maintain.


Oregon Composting Regulations

The Oregon Department of Environmental Quality (DEQ) revised its composting regulations, in 2009 and again in 2019, in order to facilitate composting and limit negative environmental consequences of poorly operated compost facilities. The Oregon DEQ states that composting helps achieve several state goals including: preventing the release of methane (a potent greenhouse gas emitted from anaerobic decomposition in landfills), improving soil fertility, and contributing to the state’s goal of reducing food waste by 50 percent by 2030.

Changes to Oregon’s rules expand the variety of feedstocks deemed acceptable for agricultural composters to use, but require agricultural composters be held to the same performance standards as all other types of operations. The changes also “give operators the responsibility and flexibility to design, construct, and manage their operations – subject to DEQ approval – to meet the performance standards.”

In order to collect stakeholder input prior to the rules revision, the DEQ consulted members of the commercial refuse and recycling industry, the Composting Council of Oregon, agricultural composters, and regional governments. The DEQ also met with the Oregon Department of Agriculture and the Oregon State University Extension Service. In addition, the DEQ convened a workshop for agricultural composters.


Composting Permit and Exemptions

Oregon requires most compost facilities to apply for a permit from the Department of Environmental Quality. However, in order to facilitate increased composting, Oregon conditionally allows some operations to compost small quantities of certain materials without a permit. In general, facilities processing under 100 tons of feedstock per year are exempt from screening and permitting. These conditional exemptions from the permit requirement can be revoked if specific performance standards are not met.

The Oregon Department of Environmental Quality’s website states: “DEQ supports and encourages composting. At the same time, DEQ is aware that, if not conducted in the proper manner, or if conducted at an improper location, composting presents potential environmental problems, most notably to surface water and groundwater.” Hence, Oregon’s regulations, as amended in 2009, are tailored to both facilitate beneficial small-scale compositing and protect the environment.

According to Oregon Administrative Rules (OAR) 340-096-0060, Oregon allows the following conditional exemptions of facilities from obtaining a permit:

  • Composting less than 100 tons of Type 1, or Type 2, or both types of these feedstocks during a calendar year
  • Composting less than 20 tons of Type 3 feedstock during a calendar year
  • Composting less than 40 tons of Type 3 feedstock with in-vessel container system (which are designed to prevent vectors and nuisances)
  • Composting operations that produce silage on a farm for animal feed
  • Home composting operations


Performance-based Standards and Site Requirements

In order to apply performance-based standards and site requirements based on the size and potential environmental consequences of the material being composted, Oregon separates various types of compostables into three types. These regulations are found in OAR Section 340-093-0030.

Feedstock Tier


Hazard Level Posed

Type 1 feedstocks “Source-separated yard and garden wastes, wood wastes, agricultural crop residues, wax-coated cardboard, vegetative food wastes including department approved industrially produced vegetative food waste”

Other materials as determined by the department

Determined by the Dept. to pose a low level of risk from hazardous substances, physical contaminants, and human pathogens
Type 2 feedstocks Manure and bedding

Other materials as determined by department

Determined by the Dept. to pose a low level of risk from hazardous substances and physical contaminants, but a higher level of risk from human pathogens compared to Type 1 feedstock


Type 3 


Dead animals

Meat and source-separated mixed food waste

Industrially produced non-vegetative food waste

Determined by the Dept. to pose a low level of risk from hazardous substances and a higher level of risk from physical contaminants and human pathogens compared to Type 1 and 2 feedstocks


Oregon has differing requirements based on the feedstock types above; examples of these requirements are listed below. For more information see Oregon Administrative Rules, Division 96.

Specific information about the site and conditions of the compost facility must be submitted with the initial application. These regulations relating to screening of compost facilities by the state can be found in O.A.R. Section 340-096-0080. They include physical information such as location, distance to surface water, soil types, wind direction, and other factors.

In addition, there are regulations aimed at preventing nuisance and environmental damage that may result from the compost site. These regulations vary based on the type of organic material being processed. The most significant differences relate to pathogen reduction. For example, “if less than 2,500 tons of composted material from Type 1 and 2 feedstocks are produced per year, testing must be conducted once a year.” However, the same amount of Type 3 material must be tested every four months due to its higher risk level.

The specific performance standards for compost facilities are listed in OAR 340-096-0070; additional stipulations on “Special Rules Pertaining to Pathogen Reduction” are in section 340-096-0140. Some of these performance standards include:

  • Designing and operating the facility in a way that does not cause an unsafe discharge of leachate or stormwater runoff from the facility to surface water
  • Designing and operating in a way that prevents odors that cause adverse impacts beyond the boundaries of the facility
  • Achieving human pathogen reduction by ensuring Salmonella analysis results in “less than 3 Most Probable Number per 4 grams of total solids (dry weight)” and “fecal coliform analysis must result in less than 1,000 Most Probable Number per gram of total solids (dry weight)”
  • In order to prevent human pathogens, compost facilities that use either an in-vessel composting method or the static aerated pile composting method must maintain a temperature in the active compost pile of at least 55 degrees Celsius or higher for three days.
  • Facilities using a windrow composting method must maintain a temperature of 55 degrees Celsius or higher for 15 days or longer. During the period when the compost is maintained at 55 degrees Celsius or higher, there must be a minimum of five turnings of the windrow.


State Financial Assistance to Facilitate Composting

The Oregon Department of Environmental Quality charges a fee on every ton of domestic waste deposited in landfills. The money raised by the fee is used to make grants to local governments and partnering individuals or organizations that propose ideas to improve recycling, reuse, composting, household hazardous waste disposal, and the rate of materials diverted from landfills. According to a 2020 DEQ Materials Management publication, the Oregon DEQ has awarded over $9 million in grants since 1991. The funded projects have fostered innovations in recycling and advanced community development.

One example of a grant recipient is the ACCESS Inc. Food Rescue Program in Jackson County. In collaboration with Jackson County, ACCESS Inc. created a network of food service professionals that donate edible food that would otherwise be discarded. This food is then distributed to local low-income residents. The program collects 50 tons of food annually, which benefits 37 social service and community groups.


More Information

Original post from July 30, 2012
Updated August 2, 2021