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Failing septic systems can expose you, your family, and your neighbors to sewage, which contains pathogens and viruses that can make your family and pets sick. Additionally, sewage can impact ground and surface water, possibly polluting wells, rivers, streams, or lakes near your home.

Failure warning signs

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

Drainfield trench failure anatomy

Trench failure anatomy

Trench failure detail

Trench failure detail

Trench failure — surface detail

Trench failure surface detail

Trench failure — during repair

Trench failure during repair

Take action

If you think your septic system is failing, contact one of the following professionals to confirm the location and possible cause of the failure and learn of repair options. Remember, septic system repairs require a repair permit from Public Health — Seattle & King County.

  • Public Health - Seattle & King County can confirm the failure. If necessary, a dye test may be performed to check if surfacing sewage is from your septic system. Contact the Eastgate Environmental Health office for assistance at 206-477-8050.
  • Contact a certified Installer, licensed Designer, or qualified professional Engineer to examine the septic system and submit a repair proposal to Public Health.
    • A Certified Maintainer can investigate causes of septic system backups or slow-draining fixtures.
    • A licensed designer will design a repair for your septic system that takes the characteristics of your property into consideration. They will submit a repair application to Public Health.

Repair tips

  • A failing septic system may not have to be replaced with a new system. Your septic system professional can advise you on your repair options.

  • While it may be necessary to have the tank pumped during the repair process, pumping the tank alone may not correct a failing septic system.

  • The Craft3 Clean Water Loan Program offers affordable loans to repair or replace failing on-site sewage systems. The loan program is available throughout King County. Learn more about this program as well as other funding resources.

Learn about the jetting of failing septic systems.