The Safe Drinking Water Act of 1974 mandates that water suppliers ensure that the water that is being delivered to consumers meet federal drinking water standards and that water quality not be compromised in the distribution system. Golden State Water Company, through implementation of a Cross-Connection Control Program, safeguards it distribution system from unwatned backflow that can jeopardize water quality in the distribution system. In this manner the Safe Drinking Water Act requirement is satisfied.

Program Overview

Golden State Water Company’s Cross-Connection Control Program (CCCP):

• Safeguards our communities drinking water by surveying and identifying customer facilities from potential and/or existing cross-connection hazards.
• Provides information on how customers can protect and safeguard  the public water system from unwanted backflow & cross-connections.  
•  Ensures backflow assemblies in the water system are in compliance with all state regulatory requirements.

Defining Cross-Connection

Cross connections are plumbing setups that can provide a direct pathway for contaminated substances to enter the potable water supply. The most common cross-connection in a residential setting is a water hose whose inlet has been left submerged in a container with non-potable water.

Understanding Backflow, Backsiphonage, And Backpressure

Under typical conditions, potable water would only flow from the public water system into customer homes and businesses. The real world, however, is more complicated than that. Under the right conditions water that has made its way into customer plumbing systems can make its way back to the public water system. When this type of flow reversal occurs, we refer to it as backflow. There are (2) hydraulic conditions that can cause backflow: .

1. Backpressure: Occurs when water pressure in the customer plumbing system exceeds the public water system pressure.
2. Backsiphonage: Occurs when there is a sudden reduction of pressure in the public water system. Pressure can suddenly drop if there is a firefighting event, broken water main, or other high water demands by end users.

Why It Matters

Cross-connections are a public health concern because any water that is reintroduced into the public water system has the potential to carry contaminants from the customer’s premises. In this way, cross-connections can compromise the quality of the public water supply.

Taking Measures To Protect Our Communities Water Supply

Backflow assemblies, installed downstream of the water meter, offer a mechanism by which GSWC can ensure contaminated water does not flow back into the public water system. Backflow assemblies act as check valves that allow water to flow only in one direction - from the public water system into homes and businesses.

Not all backflow assemblies are created equal; some offering a higher level of protection than others. In the event that GSWC requires the installment of a backflow assembly, the water user will be provided with a letter indicating the type of backflow assembly/method that needs to be installed/implemented.

Approved Assembly Types & Method For Backflow Prevention

Pressure Vaccum Breaker Assembly (PVB)

This assembly contains a check valve and an independently operating loaded air inlet valve. It is designed to protect against a non-health and health hazards under a backsiphonage hydraulic conditions only.

Double Check Valve Assembly (DC)

This assembly has two independently acting check valves in series. The assembly is designed to protect against non-health hazards under a backpressure or backsiphonage hydraulic condition.

Double Check Detector Assembly (DCDA)

Similar to the DC assembly, but contains an approved bypass line with a water meter. The meter is included to detect leaks and also unauthorized illegal taps on the customer plumbing system. The bypass line is equipped with a DC assembly also. This type of assembly is commonly used in fire protection systems, posing a non-health hazard to the public water supply.

Reduced Pressure Principle Assembly (RP)

This assembly contains two check valves and a differential relieve valve. The assembly is designed to protect against non-health or health hazards under backpressure and backsiphonage hydraulic conditions.

Reduced Pressure Principle Detector Assembly (RPDA)

Similar to the RP assembly, but contains an approved bypass line with a water meter. The meter is included to detect leaks and also unauthorized illegal taps on the customer plumbing system. The bypass line is equipped with an RP assembly also. This type of assembly is commonly used in fire protection systems posing a health hazard to the public water supply.

The Air Gap (An Approved Backflow Prevention Method)

The most effective form of backflow prevention is the air gap—a physical separation between a water supply outlet and the highest potential water level in a receiving vessel. The air gap eliminating the possibility of backflow due to the absence of a direct connection to the supplying piping.The physical separation is a vertical distance spec­ified by regulations.

Customer Responsibilities

Customers must:

• Install and maintain backflow preventer assemblies as required by Golden State Water Company.
• Ensure that backflow assemblies are tested annually by a certified tester and provide test results to Golden State Water Company. In specific cases, GSWC may require a higher testing frequency on an assembly.
• Report to the CCCP group any changes in water usage or plumbing within their facilities that could introduce or alter cross-connection risks. Please email backflowtest@gswater.com or call (310)-977-7368.

Company Responsibilities

Golden State Water Company will: 

• Identify cross-connection hazards by surveying customer facilities.
• Provide information and guidance on how to install and maintain backflow assemblies.
• Ensure adherence to backflow prevention regulations.
• Uphold the safety and reliability of the water being supplied to our customers.

Backflow can lead to serious chemical or microbiological contamination in distribution systems.

For example, water in an irrigation system can contain fertilizers or soil-borne bacteria and parasites. If this water were to flow back into the public water supply during a backflow event, it would contaminate the water supply and pose a public health risk to you and others on the water system. A backflow prevention assembly would prevent the contaminated water from entering the public water system.

Below is a list of commonly asked questions about cross-connections, backflow prevention assemblies, and annual testing requirements. If you require additional assistance, email backflowtest@gswater.com.

Frequently Asked Questions

Why do I need a backflow prevention assembly installed at my meter? 

State regulations require certain premises and business types to install backflow assemblies.  For those not explicitly required, a hazard assessment is conducted to determine if a backflow assembly is necessary to safeguard the public water supply from potential or actual contamination.

How can I prevent backflow and potential contamination?

Backflow prevention assemblies, such  as reduced-pressure assemblies or double-check assemblies, are crucial safeguards against water contamination. They prevent unwanted backflow, reducing the risk of potential harm to the water supply. Golden State Water Company has adopted standard specifications for installing backflow prevention assemblies.

How can I find a Certified Backflow Prevention Assembly (BFA) and Tester?

Golden State Water Company cannot recommend testers, nor do we maintain a list of certified testers. If you need a tester:

• Consult with your current plumber or contractor. These professionals usually hold backflow tester certification or know someone who can test your assembly. PLEASE NOTE: Whomever you select to test your BFA must be certified to do so. You should confirm that the plumber or contractor you select as a tester is certified. Testers must hold a current certification from the county, American Backflow Prevention Association (ABPA) or American Water Works Association (AWWA). Please contact us if you are uncertain that your tester’s certification is acceptable.
• Search online using keywords such as “Backflow”, “Testers”, “Cross-Connection”, etc.
• Check your assembly. In some cases, the existing BFA has been tested before and would have a tag from the previous tester that shows the tester/ testing company’s phone number.

The backflow tester should use the annual test form supplied by Golden State Water Company, since it is pre-populated with unique identification numbers. If it is not available, the tester may use this approved  blank form (click here).

Where can I find additional resources? 

EPA Cross Connection Control Manual
Rule 16: Service Connections, Meters, and Customer’s Facilities
Division of Drinking Water Cross Connection Control Policy Handbook
List of Approved Backflow Prevention Assemblies
Change of Mailing Address Request Form

P-35 Backflow Prevention Assembly Overview for Above Ground Installation
P-35-Backflow-Prevention Assembly for Fire Services Standard Drawing