Backflow / Cross Connection

Backflow Prevention and Cross Connection Control Program

The program is designed to set standards for backflow prevention assembly installation, maintenance, and testing that will systematically and effectively help to prevent contamination or pollution of the ONWASA potable water supply.

Cross Connection

A cross connection is a temporary or permanent connection between the public water supply and a source of non-potable water. One example of this is the piping between a customer's drinking water supply and an irrigation or sprinkler system. View more on the Cross Connection Control Program here.


All backflow prevention assemblies must be installed by a licensed plumber.

Proper installation - Diagram 1

Manufacturer's Specifications, Warranty Information, and Weatherization

For manufacturer's specifications and warranty information on your backflow prevention assembly, as well as tips on proper weatherization, click here.

Testing Backflow 

ONWASA's cross connection regulations require that all backflow prevention assemblies be tested annually by a certified tester. .

Backflow Prevention Test and Maintenance Report