Comprehensive Plan 2040:

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Backflow & Cross-Connection Control

Water normally flows from the City’s water lines to your home or business.  However, when backpressure or backsiphonage conditions occur, the flow of water can reverse and flow back into the community drinking water supply. Without proper protection, the drinking water supply may become contaminated and jeopardize public health.

To prevent backflow into the community water supply, the City must protect against the actual or physical connections through which contaminates can enter (known as cross-connections).  When cross-connections cannot be eliminated, mechanical backflow preventers are used to provide a physical barrier to backflow

Determining if a Backflow Preventer is Required

The need for a backflow preventer is determined by the degree of hazard to the public drinking water system.  Examples of water services that require backflow preventers include:

  • Premises with an irrigation system using potable water connected via a dedicated irrigation service line
  • Premises with fire protection systems using potable water
  • Specific categories of non-residential customers, such as restaurants, hair salons, car wash facilities, laboratories, processing or industrial facilities

To find out if a backflow preventer is required, complete the Cross-Connection Control Program Facility Questionnaire and return to

Backflow preventers must be tested by a certified backflow prevention assembly BackflowPreventertester immediately after installation or repair, then annually thereafter and must be repaired if they fail to meet performance standards.  Mechanical backflow prevention assemblies consist of springs and seals, which are subject to fouling and fatigue. Having the backflow assembly tested annually ensures that it is in working order and is adequately protecting the public water supply. All test reports must be submitted to the City of St. Augustine Public Works Department.

Cross-Connection Control Documents and Forms
List of Approved Backflow Preventers
Backflow Preventer Installation Guidelines
Backflow Preventer Test Report
Cross-Connection Control Facility Questionnaire