Septic System

All septic systems have a limited life expectancy so one can expect that they will fail at some point in time. Failing septic systems can expose you, your family and your neighbors to sewage, containing pathogens that can cause disease. Sewage can also contaminate ground and surface water, polluting wells, rivers, and creeks near your home.

You may know your septic system is failing if there are:

  • Bad odors around the drain field, especially after heavy rains or heavy water use
  • Very wet spots with lush green grass growth over the drainfield or septic tank areas
  • Gurgling sounds in the plumbing system
  • Plumbing or septic tank back-ups
  • Slow draining fixtures
  • Standing water in the drainfield

King County Board of Health Code

The King County Board of Health code requires all septic owners to maintain their systems to protect and preserve public health. Septic systems require maintenance every 3 to 6 months with Mound and Sand Filter systems, every 6 to 12 months for some Pressure Distribution systems, or every 1 to 3 years for Gravity systems. The presence of Aerobic Treatment Units (ATUs) and household garbage disposals can affect inspection frequency.

Inspect & Monitor Your System

Contact a certified On-site System Maintainer (OSM) to inspect and monitor your system on a regular basis to extend its useful life. A certified OSM has two or more years of experience, has completed a monitoring and maintenance class and has passed an exam given by Public Health - Seattle and King County.

Your septic system is considered "non-functioning" if sewage is surfacing on the ground and routine maintenance cannot fix it. If this is the case, you should contact the Public Works Department immediately to determine your best course of action.

More Information

For more information on septic systems, proper maintenance, and how to find a certified OSM, please visit the King County Public Health website.  Please note this is an external website, and not all information may apply to residents within the Snoqualmie city limits.

  1. Tom Holmes

    Wastewater Supervisor
    Phone: 425-888-4153, ext. 1159