Septic System Maintenance & Evaluation

Links to online septic system records
Links to list of licensed septic professionals
Links to homeowner training information
Links to information about septic rebate program
Icon links to septic safety page
Links to basic septic maintenance information

Septic systems, also known as on-site sewage systems (OSS), treat sewage so it doesn’t contaminate local rivers, lakes, and groundwater. Just like your home or car, your septic system needs to be monitored and maintained regularly. This can reduce the chance that you’ll need to do major, costly repairs to your system because you’ll catch small problems before they become big ones.

What is a septic system evaluation?

A septic evaluation is a required inspection of all the components of your septic system: septic tank, pump tank (if you have one) and drainfield.

Some of the things checked during an evaluation are:

  • The tanks are checked to make sure they are not leaking.
  • The sludge and scum levels are measured in the tank to determine if the tanks should be pumped.
  • The drainfield is checked with a flow test to see if it is performing properly and inspected to see if any sewage is pooling.
Septic system maintenance infographic

You can hire a professional to perform a septic evaluation. Depending on your system type and the purpose of the evaluation, you can also do it yourself. To learn if and how you can complete your own evaluation, see the “Who can perform a septic evaluation?” section.

When do you need a septic evaluation?

Some types of septic systems need to be checked more often than others.

  • Conventional gravity systems need to be evaluated every 3 years
  • All other types of septic systems need to be evaluated once a year (unless the manufacturer specifies they should be inspected more frequently)
  • All septic systems that serve a food service establishment must be inspected once every year.

When a property is offered for sale, a current inspection report, called a “Report of System Status” (ROSS), must be on file with the Whatcom County Health and Community Services.

Who can perform a septic evaluation?

A septic evaluation can be done by a licensed professional, also called an Operations & Maintenance (O&M) Specialist. These professionals work for private businesses and have been licensed by Whatcom County Health and Community Services.

Homeowners can also become certified to complete their own septic evaluation by taking a free training offered by the Whatcom County Health and Community Services.

Homeowners CANNOT complete their own evaluations if any of the following apply:

  • The septic system is connected to a community drainfield
  • The system serves a restaurant or other food service establishment
  • The system is being evaluated for a sale or property transfer
  • The septic system uses a proprietary technology (Some examples are Glendon Biofilter, OSCAR, and ATU)
  • The system was considered “non-conforming” when it was replaced

Please contact us at (360)778-6000 if you are unsure your septic system uses proprietary technology or was “non-conforming”.

Licensed Septic Professionals in Whatcom County

How much does a septic evaluation cost?

Septic evaluation costs vary depending on your specific system. To get information on costs, contact a licensed professional to get a quote. 

Financial help is available for failing septic systems or repairs in some cases.

  • Whatcom County Septic Maintenance Rebate Program – helps cover the costs of septic evaluations, pumping, and equipment installation. Learn more at the Septic Maintenance Rebate Program page. 
  • Clean Water Loans to finance septic repairs - Craft3, a nonprofit lender, offers Clean Water Loans to allow homeowners to borrow the entire cost of eligible design, permitting and installation. Lower interest rates may be available for qualified lower-income borrowers, with no up-front loan fees or pre-payment penalties. Please visit Craft3’s Clean Water Loans page for rates and terms, to check eligibility, and begin your application.


 The educational materials for the “EVALUATE before it’s too late” campaign have been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement PC-01J18001 through the Washington State Department of Health. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency or the Washington State Department of Health, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.