Welcome

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
E-mail
health@co.walla-walla.wa.us

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

Mound System

The sewage from your house enters a large two compartment septic tank, where the solids settle out. The liquid (effluent) then flows to a pump tank where it is pumped to a mound system which consists of a raised mound of coarse sand media. Within the sand fill is a gravel bed with a network of pressurized pipes. Effluent is pumped through the pipes and trickles down into the gravel and sand layer where treatment takes place before reaching the soil. The soil filters and further treats the effluent, removing bacteria and other pollutants before reaching the groundwater.

Areas of concern for maintenance

    1. Septic Tank: The septic tank needs to be pumped out every 3-5 year.
    2. Pump Chamber: The pump chamber is a chamber similar to a septic tank that contains a pump and a series of floats. the flows are used to turn the pump on and off. There is also a float that is called a high water alarm when the high water alarm is activated there is a loud noise and sometimes a light is turned on at the control panel this indicated that the pump is no longer working a effluent is building up in the pump chamber and septic tank an will soon surface. The floats in the pump chamber need to be inspected every year.
    3. Effluent Filter: The effluent filter is a plastic filter that is installed in the septic tank on the outlet side. There are 1/4" slots in the filter that allow effluent from the tank to enter the pump chamber. This filter need to be check for clogs at least once a year.

Below are some useful educational material specific to caring for your Mound System

Understanding and Caring for Your Mound System  Click Here
Provided by Washington State Department of Health

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