Introduction to Backflow Prevention and Cross-Connection Control
A “cross-connection” is a physical arrangement where the public potable (drinking) water supply is threatened by the introduction of an unwanted foreign substance or contaminant due to an illegal or incorrect connection. Cross-connections most often occur when water flows in the wrong direction; i.e., from the customers side of the meter to the distribution system. This is referred to as “backflow.” To prevent cross-connections and backflow, special devices called “backflow preventers,” or “backflow prevention devices,” are used to keep the water flowing in one direction from the distribution main to the customer. The exact required backflow prevention device is determined by the hazard level posed to the public water supply by the property in question. For example, a hotel or a restaurant would require a form of backflow prevention that provides greater protection than one used for a home. Table B-1 provides a summary of the different backflow prevention devices and their properties appropriate for the given contamination threat. Cross-connections between public water supplies and non-potable sources of contamination pose significant threats to the health, safety, and welfare of the people of Guam. Water utilities throughout the world have developed and implemented programs to mitigate the threat of cross-connections to the public water supply. To provide proper sanitary protection to GWA’s water supply, and to comply with the applicable regulations, Guam law Title 28, Guam Administrative Rules and Regulations (GAR) Section 2114(a) requires that no cross connections with other water supplies or other physical connections shall exist or be installed, located, maintained or operated which could permit backflow of contaminated water or any other dangerous, impure, unsanitary or un-potable substance from the customer’s premises into GWA’s water supply system.

Strategy and Goal of the Program
Strategies and goals of the Program are as follows:
1. To protect the GWA and Guam public water supply from the possibility of contamination by isolating and
containing, at the point of connection, any unwanted contaminants which could backflow or back-siphon
into the public water system within a customer’s internal distribution system(s);
2. To promote the elimination or control of cross-connections, actual or potential, between customer’s inplant
drinking water system(s) and anything that could contaminate or pollute it; and
3. To provide for the maintenance of a cross-connection control program to effectively prevent the
contamination or pollution of all drinking water systems.

Legal Authority Summary
The following authorities govern the responsibility of preventing water from unapproved sources, or any other
harmful substances, from entering the public potable water system:
1. The Federal Safe Drinking Water Act of 1974, as amended;
2. The laws, rules and regulations of Guam as amended, including:
a. Title 12 Guam Code Annotated Chapter 14 (Guam Waterworks Authority Act);
b. 22 GAR
. Chapter 7, Part II (Guam Environmental Protection Agency Guidelines for Water Works
Development);
c. 28 GAR. Chapter 2, Article 1 – Rates & Services; and
3. Hawaii Water System Standards 2002, as adopted by the Consolidated Commission on Utilities through
the GWA Water Resources Master Plan 2007 (CCU Resolution No. 11-FY20070).
The stated purpose of the Safe Drinking Water Act of 1974 is to protect the public water supplies from
contamination and require the provision of safe drinking water for public consumption to protect human
health and safety to the greatest degree practicable. This act provides GWA’s staff with the legal authority to
enter at all reasonable times in or upon any property served by the public water system for the purpose of
inspecting and investigating the adequacy and sanitary condition of the water supply and the quality of its
water. All plumbing work carried out on GWA’s water system must be compliant with the most current
version of the International Plumbing Code adopted by the government of Guam as a part of the
International Building Code.

Summary of Policies
At all times, GWA may conduct an inspection, survey, or evaluation of the cross-connection hazards of any
premises to which it serves water. Existing backflow devices will be allowed to continue in service if the
degree of hazard within the system has not increased. If upon inspection it is found that the device is no
longer adequate, GWA staff will contact the customer in writing informing them of:
1. The required corrective action deemed necessary; and
2. The time allowed for the correction.
All new service connection requests will be reviewed by GWA to assess the need for a backflow prevention
device. If backflow protection is deemed necessary, the required device must be furnished and installed to
GWA’s specifications by the customer.
Email:cccp@guamwaterworks.org