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

Sand Line Trench

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 out to a network of pipes lying in a sand bed buried in the ground. The effluent leaves the pipes under low pressure through small diameter holes, and trickles downward through the sand layer where it reaches 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 Sand Line Trench

Understanding and Caring for your Sand Filter Click Here
Provided by Washington State Department of Health

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