Oregon Septic System Requirements

In Oregon, all residential properties are required to have a septic system. Your property’s size and nature determine the requirements to protect the groundwater from leachate and soil contamination. A septic system is designed to remove the waste from your household. Septic systems are regulated by Oregon State law and your local county health department. The county health department issues the state-required Permit to Construct, and septic system inspections are conducted by the county health department and state agencies such as water quality or natural resources departments. This article will go over all of your Oregon septic system requirements.

A septic system consists of a septic tank, an underground distribution tank, and two underground absorption areas that allow the tank effluent to soak into the ground. Commonly, a mound of earth is designed over the final absorption area.

The following are required when designing and installing a new septic system in Oregon:

• The property must be evaluated by a professional engineer or geologist who will determine if there is an adequate soil absorption area.
• The soil absorption area must have a minimum depth of 8 feet and a minimum diameter of 0.5 feet.
• A septic system must be designed to accommodate the flow rate of the residence. A flow rate test is required on residences with more than 2 bedrooms before installation approval will be issued. 
• The residence will also require an annual operating performance evaluation by a septic system professional who will confirm that the design and operation of the system are still adequate for continued compliance with code requirements.
• The septic system must be sized for the residence based on the total wastewater volume anticipated over 30 years for a new building. A professional engineer or geologist must evaluate the soil absorption area and determine its suitability.
• For remodeling, repair, and replacement of any part of an existing septic system, a local health department requires a permit. In addition to a new Permit to Construct, you may also require an individual Permit to Operate for parts of your system that have been replaced.
• All septic systems are required to have a state-approved backflow prevention device installed at the entrance pipe to the system. If you are adding or replacing a portion of your septic system, there is a Rebuild Permit and any permits that may be required. 
• Septic Systems in Oregon are required to have a state-approved pretreatment device or treatment plan. 
• The intake pipe must be sized to accommodate the flow rate from the residence. The county health department requires results of a performance test before a Permit to Operate will be issued.
• The septic system must have an automatic float switch installed at the main outlet pipe of the septic system. This is required by all new development and all remodeling, repair, and replacement.

Suppose you are planning to install a new Oregon septic tank or replace property lines. In that case, the septic system must be sized according to the Permit to Construct. The size of your existing Oregon septic tank is based on the flow rate from your residence, and a performance test will be required prior to the issuance of a Permit To Operate. If you are looking to understand these requirements better, we can assist in guiding you through the process.

If you are remodeling, repairing, or replacing parts of an existing septic system, you will receive a Rebuild Permit. The following permits may also be required prior to issuing a Permit To Operate:

Property owners should contact their local health department for more specific information on permits, including the fee and the time required to inspect septic systems.

For many people, like those in areas of Oregon with higher population density, septic systems handle more than just household sewage. In urbanized areas, residential septic systems are used to dispose of the entire contents of a home’s water system.

Are you seeking more information about the Oregon septic system, or perhaps you’re unsure about the Oregon septic drainfield requirements? If you have any questions, our knowledgeable team can help guide you to make the best decision. Contact us for more details about Oregon septic drainfield requirements and any other concerns you might have regarding your septic system. We’re here to help.