Backflow Prevention Program

Did you know common hazards exist around homes and businesses that can contaminate your drinking water as well as your neighbor’s? The City of Lacey is committed to protecting the public water system. Learn about the actions the City is taking and how you can help to make sure our water supply stays safe and reliable all day, every day.

What is a cross-connection? What is backflow?

What is a cross-connection?

A cross-connection is any point where the public water supply meets an actual or potential source of nonpotable liquid, solid, or gas in a connection to a home, business, irrigation system, etc. that could contaminate the public water supply by backflow.

What is backflow?

Backflow is the unwanted flow of water in the reverse direction. This means that water flows backward from your home or business into the public water supply.

There are two types and causes of backflow: backsiphonage and backpressure.

Backsiphonage means backflow due to a reduction in system pressure in Lacey’s water distribution system. This is a normal and common occurrence due to firefighting, water line flushing, or water line breaks.

Backpressure means a pressure (caused by a pump, elevated tank or piping, boiler, or other means) on the consumer’s side of the service connection that is greater than the pressure provided by the public water system which may cause backflow.

The danger? Backflow can carry contaminated water into the public water supply.

The degree of hazard depends on the type of substance which may flow into the drinking water supply at the point of cross-connection.

  1. A low cross-connection hazard refers to any substance which would affect the color or odor of the water but is considered a non-health hazard.
  2. A high health cross-connection hazard refers to any substance that causes illness or death if ingested and is considered a health hazard.
  3. A severe health cross connection hazard refers to extreme hazards including sewage treatment plants and nuclear facilities because of the epidemic possibilities and dangers associated with them.

Washington State Law requires that water purveyors establish and implement a cross-connection control program to protect the public water system from these hazards. The public water system begins at the source of water (in Lacey the source of water is a well) and ends at the service connection to the customer, the water meter.

The installation or maintenance of any uncontrolled cross-connection which could endanger the quality of the City’s public water system is prohibited. Any such cross-connection is unlawful and should be abated immediately. Abatement includes, but is not limited to, discontinuance of water service or the installation of an approved backflow prevention assembly, equal to the degree of hazard, as determined by the City.

The customer is responsible for backflow prevention assembly installation, initial testing, and annual testing thereafter by a licensed tester. The customer is required to provide proof of installation and proof of a passing test to the Public Works Department by the annual due date. The City will mail affected customers an annual reminder, but it is your responsibility as the water customer to ensure testing is completed.

Service shall be discontinued to any premises, water user, or property owner for failure to comply with rules and regulations pertaining to the City’s cross-connection program or failure to permit entry upon the premises by authorized City personnel for purposes of inspection and/or testing.

For more information about this program, please see the City of Lacey Development Guidelines and Public Works Standards, or contact the City’s Cross-control Specialist at (360) 413-4341.

Residential Cross-Connections – What are your responsibilities?

The most common household cross connections include the following:

Garden hoses

Any hose is a cross connection when left submerged in a swimming pool, laundry sink, car wash bucket, puddle, etc. To protect against this type of cross-connection, check to see if you have an air vacuum breaker installed on each of your outdoor hose bibs. These simple devices are inexpensive and can be purchased from your local hardware store. They are easy to install and usually you just have to screw them on.

In-Ground Irrigation System

In-ground irrigation systems are one of the most common cross-connection found in Lacey’s water system. Washington Administrative Code (WAC) 246-290-490 and Lacey Municipal Code (LMC) 13.48.070 require that all irrigation systems be isolated from the water system with a special set of valves called a backflow prevention assembly.

If your property has an in-ground irrigation system it is your responsibility to make sure these steps are followed.

  1. Confirm that your irrigation system has an approved backflow assembly. This is usually a brass valve found between your water meter and the point of connection to your irrigation system.
  2. Test the backflow prevention assembly annually.
    The assembly must be tested by a Washington State Department of Health certified Backflow Assembly Tester (BAT) immediately upon installation, following any repairs, and annually thereafter.
    List of Certified Backflow Assembly Testers
    Blank Backflow Prevention Assembly Test Report
  3. Make sure the test results are reported to Lacey PW/Water Resources. Normally, your hired BAT will submit the test results to the City for you, but it is your responsibility to make sure the test results are submitted in a timely manner.

You will continue to receive overdue testing notices until passing test results are received by the City.

Test results should be submitted to, or:
City of Lacey Water Resources
ATTN: Cross Connection Specialist
420 College St. SE
Lacey, WA 98503

An overview of this information can be found here:Residential Backflow Brochure

We are here to help! If you have any questions, please contact:

Branden Clark
Cross-connection Specialist
(360) 413-4341

Commercial Cross-Connections – What are your businesses’ responsibilities?

To ensure the safety of our community’s water system, backflow assemblies are required for applications that have the potential of contaminating the drinking water supply and are chosen based on the degree of hazard at each location.

  1. Low cross-connection hazards require:
    Double Check Valve Assembly (DCVA/DCDA)
    These are the most common assemblies in the Lacey water system. Most are installed below ground in a valve box or vault for irrigation or fire sprinkler systems.
    Spill resistant vacuum breaker
    These are when water spillage is undesired. They protect against backsiphonage only and are not to be used under constant pressure applications.
  2. High health cross-connection hazards require:
    Reduced pressure backflow assembly (RPBA/RPDA)
    These are required and very important in commercial settings where hazardous material could enter potable drinking water.
    RPBA use is required for any mobile or temporary apparatus that connects to the City water system by way of a fire hydrant or other temporary water connection.
    They are also used with higher-level fire systems, irrigation systems that distribute fertilizers, in medical facilities, chemical plants, etc. RPBAs protect against both low and high health cross-connection hazards.
  3. Severe health cross connection hazards require:
    Air gap separation
    This method is used in commercial applications where reservoirs and storage tanks are required. It protects against all levels of cross-connection hazards. An air gap means there is a physical break between the city’s water supply and the facility’s process therefore providing the utmost protection.

Universal Installation Requirements for all of the following backflow methods can be found here: Commercial Backflow Brochure

Discontinued Use of Hazard- What if you remove a cross-connection?

If at any time you believe there is no longer an actual or potential cross-connection on your premises, you may request an inspection to verify elimination of the hazard and discontinued use of your backflow assembly (or assemblies) and exemption from further testing requirements. As long as the connection exists, backflow protection and testing is required, regardless of whether the system is used.

Example:  “I don’t use my sprinkler anymore”

If the use of your in-ground irrigation system is no longer desired, the system may be decommissioned by completing the following:

  1. Remove visible sprinkler heads and distribution lines.
  2. Remove the existing backflow assembly and cap the water supply line.
  3. The remaining water line may be buried once inspected.
  4. Remove plastic or concrete boxes and backfill.

To request an inspection, contact Ashley Smith at (360) 413-4341 or at

Public Works


phone: (360) 491-5600

Monday - Friday: 9:00 am - 5:00 pm