Onsite Septic

Think of onsite septic systems like a sewage treatment plant, only much smaller. They store, treat and dispose of the things you flush or send down drains. There are many different types of systems. Some are simple, using only a tank and a drainfield. Others are more complex, requiring pumps, filters, or specially designed materials.

New Onsite Septic Systems

Building, splitting, or altering your property?

​If you are developing your land, you may need to schedule a site evaluation with Whitman County Public Health to begin the permitting process.

Details on the permitting process are included in-detail below.

Current Onsite Septic Systems

Buying or selling property with a septic system? ​

A System Assessment Form, linked below, completed by a Licensed Evaluator is required prior to property transfer.

Step 1: Site Evaluation

• Submit the Site Evaluation Application, linked below. An WCPH Environmental Health Specialist will contact you to schedule a site evaluation.

• At site evaluation, soil conditions and any site restrictions will be identified. Drainfield requirements will be presented based on project.
• Site Evaluation Reports are good for 3 years and are project specific.

Step 2 — Design & Install

• If required, contract with Licensed OSS Professionals.
• Submit the OSS Permit Application.

• ​Setback Requirements may be a helpful resource.
• Once the design is approved and all fees are paid, a Construction Permit will be issued. Building permits cannot be issued until a Construction Permit is issued.
• Schedule a final inspection before covering the system​.

Step 3 — As-Built Drawing and Final Permit

• Submit an As-Built drawing at the time of the final inspection.
• An Operational Permit will be issued once the system is approved. Certificate of Occupancy cannot be granted until an Operational Permit is issued.

Step 4 — Maintenance

• Every 3 years, hire a Licensed OSS Professional to pump and evaluate your tank.
• Return the System Assessment Form to Whitman County Public Health for record keeping.

Licensed Installer, Pumpers, and/or Evaluators

Licensed installers, pumpers, and/or evaluators are those qualified to do the following:

• Installers: Install septic systems in Whitman County, including residential gravity, residential alternative, and commercial systems.
• Pumpers: Pump septic systems in Whitman County
• Evaluators: Evaluate septic systems in Whitman County, including locating septic tank and drainfield location and evaluating their condition

Installers, pumpers, and/or evaluators are required to submit an application for approval. Pumpers must disclose the number of pumping vehicles, dispatch locations, storage location and name and location of dumping facility.

Out of County Installers & Pumpers are those licensed to install and/or pump septic systems in another county in Washington State. By submitting the Out of County application, these professionals may receive a one-time installation and/or pumping permit for work in Whitman County.