Cross-connection is any actual or potential connection between a public water supply and any other source or system through which it is possible to introduce, by backflow, any used water or substance other than the intended potable water. 

Backflow, or the reversal of the normal flow of water, can be caused by "backpressure" or "backsiphonage."

"Backpressure" occurs when the downstream water pressure exceeds the supply pressure. This can occur through a rise in the downstream pressure, a drop in the supply pressure, or a combination of both. Increases in downstream water pressure above supply water pressure can be created by booster pumps or temperature increases (e.g. in a boiler).

"Backsiphonage" occurs when the supply line pressure falls below atmospheric pressure (14.7 psi at sea level). In this situation, atmospheric pressure is creating a greater pressure on the downstream side in the reverse direction of flow, and the supply water system falls below atmospheric pressure. Decreases in the pressure of the supply water system may be caused by fire fighting, breaks in the water main, or water mains being shut down for maintenance. 

Cross Connection Certification Form

Cross Connection Control Questionnaire

Cross Connection Control Program Manual


Control & Maintenance

The City of Goose Creek is responsible for the protection of the public potable water distribution system from contamination or pollution due to the backflow of contaminants or pollutants through the water service connection.

Residential water services are classified as low hazard and come equipped with a non-testable prevention device. Commercial water customers are required to install, test, and maintain a testable backflow prevention assembly on their water service. The type of device required is dependent upon the degree of hazard posed by the service. The type of device is determined upon application for water service.

Control Devices
Each cross-connection control device on the city’s system is required to be tested and certified upon installation and annually thereafter. Certification forms must be turned in to the City of Goose Creek where they are maintained and subject to annual inspection by South Carolina Department of Health and Environmental Control (DHEC). Customers are notified when their annual inspection and certification is due.