Environmental Health Programs - On-site Sewage


Environmental Health Specialist


An environmental health specialist permits all county septic systems and licenses septic system installers and septic tank pumpers. On Site Sewage is responsible for the safe treatment and dispersion of domestic, non-industrial wastewater in areas of Kittitas County to ensure the safety and sanitary disposal of waste.

Kittitas County on-site sewage system permitting process:

  1. Site Evaluation

    To obtain an OSS installation permit you will first need to have a site evaluation on the proposed project parcel. The site evaluation is performed by an Environmental Health Specialist from the Kittitas County Public Health Department. This evaluation of soil and site characteristics will determine the suitability for an OSS on the parcel. During the evaluation, the type of OSS (gravity, pressure distribution, or alternative system), along with the soil loading rate, and other landscape and environmental factors will be determined. To obtain a site evaluation, submit the site evaluation application and applicable fee to the Kittitas County Public Health Department. Once the application has been submitted, two holes six feet in depth and three feet in width with a step side access will need to be placed in the proposed drain field and reserve drain field locations on the parcel.
  2. OSS Design

    After the site evaluation is complete, the next step will be to have an OSS design prepared by a licensed on-site sewage system designer. Homeowners may prepare their own OSS system design, but a pre-design meeting with an Environmental Health Specialist is required. To apply for an OSS installation permit and submit an OSS design, submit a sewage system installation permit application and applicable fee to KCPHD.
  3. Design approval and installation

    Once the OSS design has been reviewed and approved, KCPHD will notify the applicant of approval. This is not an issuance of an installation permit. When the OSS is ready for installation, the Kittitas County licensed OSS installer or homeowner must request the installation permit through KCPHD either via email or in-person. Once issued, the installation permit is valid for one year from the date of issuance. A one-year renewal permit may be issued if the sewage system installation permit renewal application is submitted before the expiration date of the original installation permit. Homeowners may install their own OSS system. A Kittitas County OSS Installers license is required for all septic system installers and septic tank pumpers contracting work in Kittitas County. These licenses are available through the Kittitas County Public Health Department.
  4. Inspection

    All OSS systems installed must be inspected by an Environmental Health Specialist prior to final approval. All inspection requirements, including as-built and electrical components (if applicable), must be completed prior to scheduling a final inspection. No drain field can be backfilled prior to final inspection. When the OSS system is complete, a request for final inspection can be made through KCPHD.


Licensed designer and installers may request an inspection online. You will receive a confirmation email once the requested inspection has been scheduled.