Environmental Health, Personal Health, Public Health Administration and WIC

Public Health and Legislative Building
Location - 314 W. Main Street (Rose Street Entrance)
Mail - P.O. Box 1753
Walla Walla, WA  99362

Contact Information
Phone  509.524.2650
Fax       509.524.2678

WIC Contact Information
Phone  509.524.2680
Fax       509.524.2681

Office Hours
Mon-Tue-Wed  8:00 - 5:00
Thurs   9:00 - 5:00
Fri  8:00 - 5:00
Closed 12:00 PM - 1:00 PM

Gravity Distribution Septic Systems

The sewage from your house enters a large two compartment septic tank, where the solids settle out. The liquid (effluent) then flows to the drain field where it is disbursed through perforated pipes in the gravel trenches. In some cases, a pump is utilized if the drain field is upslope from the septic tank. The effluent trickles through the gravel where it reaches the soil. The soil filters and treats the effluent, removing bacteria and other pollutants before reaching the groundwater. Properly operating and maintaining your drain field will greatly reduce the potential contamination of ground and surface water.

Areas of concern for maintenance


Septic Tank:   The septic tank needs to be pumped out every 3-5 years.

Below are some useful educational materials specific to caring for your Gravity Distribution System.

Understanding and Caring for Your Septic Tank  Click Here
Provided by Washington State Department of Health

Homeowner's Manual for the Operation, Monitoring, and Maintenance of a Gravity On-Site Sewage Treatment and Disposal System Click Here
Provided By SeaGrant