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

On-Site Sewage Systems

What is a Septic System

A septic system is a small-scale wastewater treatment plant that you own and operate. It treats and disposes of all the wastewater generated in your home or business.

Types of Septic Systems

Below are the different types of septic systems that are currently installed in Walla Walla County. You can click on the system to find more information about that system.

Gravity distribution

Pump to Gravity

Pressure Distribution

Sand Line Trench



Permitting On-Site Sewage Systems

Do I need a permit?

What is the permitting process?

Permit Application Click Here


Maintaining Your Septic System

      How a Septic System Works

Washtenaw County, Michigan has provided us with a short video that explains how a septic system works.

Do I need a permit

A permit to build or repair a septic system is required any time. (back to top)

What is the permitting process

New septic systems

When a client is proposing to build on a new lot that requires a septic system there are several items that must be checked to insure the proper septic system is installed on that parcel. The items that an Environmental Health Specialist must check on are:

  1. Lot size and location
  2. Type of water supply (public water system or individual well)
  3. How many bedrooms (This determines how big the septic system needs to be)
  4. The type of soils on that lot (This determines the type of septic system that is required a test hole may be required)
  5. Reviewing a site plan shows the location of the house, septic, well, pool, out-buildings, etc.. (this is to insure that all minimum distances are maintained).

    For a check list of the septic permit process Click Here
    For a septic permit application Click Here

If you have any questions about the permitting process please contact our office at 509.524.2662. (back to top)

Replacement of an existing septic system.

If you think you need a septic system repair, the first thing to do is contact a certified installer. The installer will be able to look at the multiple elements of your system and possibly determine where the failure is originating from.

Replacing an existing septic system requires a site visit from an Environmental Health Specialist. The site visit is to make sure there is adequate room on the property to install a new septic systems that meets all of the current regulations. If you own a septic system that needs to be replaced please contact 509.524.2662 to set up an appointment to meet with an Environmental Health Specialist. (back to top)

How to locate your system 

If we do not have an as-built for your system, you should be able to find the septic tank by probing with a steel rod gently tapped into the ground, starting five feet from where the sanitary sewer leaves your house. You may be able to use a metal detector to help you locate the tanks as they are made of concrete with rebar, and the handles on the lids are usually made of metal wire. The lids on the tank are circular, 20”-24” in diameter and 5’-5 ½’ apart. (back to top)

How to maintain your septic system

The longevity of your on site septic system relies heavily on the way that you care for it. Maintaining your system involves monitoring not only what goes into it, but also scheduling regular pumping for your septic tank and protecting the system from surface water and drainage, soil compaction, and other activities or site development that might negatively impact the system and eventually cause it to fail. Additionally, some system types require additional routine maintenance. below are some useful documents that help to protect and prolong your septic system.(back to top)

Landscaping Your Septic System
provided by Sea Grant
Water Conservation
provided by Washington Department of Health
Pumping Your Septic
provided by Sea Grant
Septic Sense
provided by Sea Grant
Understanding and Caring for Your Septic Tank System
provided by Washington Department of Health

Septic record files
Every owner of an on-site sewage system needs to know where the on-site sewage system is located in order to properly maintain it. Pumpers may charge you extra to locate and/or dig up the lids to the septic tank so that they are able to pump the septic tank. If you do not know where your system is located, you may be able to obtain this information from our offices. This document is called an “as-built,” and it is a drawing of the location of your system when it was inspected by our office after it was completed. When inquiring about a as build please have the parcel number and or the address of the lot in question.

PLEASE NOTE: Before 1975, permits were not required by law. If your system was installed before 1975, no records may be available. (back to top)

Why do septic systems fail

Septic systems do not last indefinitely, and eventually even the most well taken care of system will fail when the treatment properties of the soil in the drain field have been exhausted. A system may also fail due to poor design or installation in unsuitable soils. More often than not, though, a failing system is caused by homeowner misuse:(back to top)

Overloading the system with too much water – Septic tanks function by allowing solids to float and settle, so that relatively “clean” water from the middle layer of the tank is sent to the drain field for further treatment. By sending too much water through the system (by washing all your loads of laundry in one day, for example) you could be pushing solids into the drain field before they have a chance to settle out. This can clog up drain field components, leading to early system failure.

Using a garbage disposal when the system was not designed for it – In addition to sending lots of extra water into the septic tank, food waste does not settle or degrade well in the tank and will increase the need for more frequent pumping.

Disposing of garbage in the system – items that should go in the trash like dental floss, feminine hygiene products, condoms, diapers, cotton swabs, cigarette butts, coffee grounds, cooking fats, bones, cat litter, and paper towels won’t degrade in the tank and will increase the need for more frequent pumping. Trash can also clog inlets, outlets, and drain field components.

Overuse of chemicals – Harsh cleaning chemicals and other household chemicals can kill the bacteria in your septic tank. While they should bounce back quickly after your cleaning session. (back to top)

What are some signs of a failing system

Some signs of a failing septic system are foul odors inside or outside your house, gurgling sounds in the plumbing, sewage on the ground or soft, spongy spots in your drainfield, and/or sewage backing up into your house. By the time you see these symptoms the damage may already be done, which is why regular inspections and pumping are so important. (back to top)

Who do I contact if I’m having a problem with my system

To determine the problem, contact a certified septic tank pumping company, operation and maintenance specialist, installation company or designer/engineer for an initial assessment. Once the problem has been identified, hire the appropriate professional to fix the problem. A designer is involved if the system has to be relocated or replaced with a new type of system. An installer’s role is the construction of the system. A pumper primarily pumps and repairs the septic tank. (back to top)


Updated: 5/1/2014