Island County Public Health issues permits for new and repair construction of onsite sewage (septic) systems. The process can be very challenging for a homeowner. However, our staff is here to be a resource to you and your designer.

Our Sanitarians work with hundreds of designs a year. This, along with official certification and licenses, provides you with a public health staff that will bring creative and efficient solutions to your onsite sewage treatment needs.

The Permitting Process & General Information

Site Registration

The Site Registration (SR, Perc, etc.) is typically the first step in the process of obtaining permit(s). A Site Registration is a recorded document filed with Island County describing various conditions found on a site. A licensed designer is responsible for submitting the Site Registration. Based on the site characteristics the site may or may not be capable of supporting an on-site sewage disposal system. A typical Site Registration will provide a description of soil texture, soil depths, and water tables. The Site Evaluation does not expire and is acceptable so long as the findings remain valid. Certain activities such as grading, filling or logging of the property can alter the original findings and render the Site Registration invalid.  


Typically, the next step in the process is to apply for a permit to construct a sewage disposal system. A licensed designer will draw up a plan based on the site registration and your use of the property. The type of septic system will be either conventional or alternative depending on site conditions and use. Based on the number of bedrooms and/or water use the designer will draw a plan with septic tanks, pump tanks and drain field lines that are sufficient in size to support the use. The plan should include information such as well location, easements, utilities, dwelling size, dwelling dimensions, driveways, surface water, critical areas, and bluffs. The designer will submit a copy of the application to the Health Department for review. If the plan meets all requirements and a valid water share has been identified, a permit will be issued. The permit is valid for three years. If the permit expires before the system is installed, a new design meeting all codes must be resubmitted. At the time the permit is issued, the septic permit can be used to apply for a building permit(s).


After the sewage disposal system has been installed, the installer will draw up an as-built. The as-built will detail any deviations between the permit and what was installed. The as-built is a scaled drawing showing where dwellings, tanks, utilities, property lines, wells, drain field(s) and other important features are located. The as-built will have technical information on it as well. Items such as pump models, timer settings, dosing regimes, orifice size, residual pressures, and proprietary devices will be listed. This drawing can be used by the system owner to locate components, making system maintenance convenient.

 Minimum Horizontal Separations

Minimum Horizontal Separations

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