Backflow / Cross Connection


The Backflow and Cross Connection Division is responsible for monitoring, inspecting, and ensuring business and home owners who need to have appropriate backflow devices installed to eliminate the potential to pollute the potable water supply are informed and installed to protect the water system customers.

Backflow Prevention and Cross Connection Control Program

The program is designed to:

  • Protect the public by establishing minimum standards
  • Educate and enforce the minimum standards
  • Promote the elimination or control of existing cross connections (actual or potential) which could create backflow

The program also sets standards for backflow prevention assembly installation, maintenance, and testing that will systematically and effectively 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.

Installing Backflow Prevention Valve

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

Proper installation - Diagram 1

Manufacturer's Specifications, Warranty Information, and Weatherizing of Backflow

For manufacturer's specifications and warranty information on your backflow assembly, and to view tips on proper weatherization of a backflow prevention assembly, click here.

Testing Backflow Prevention Valve

ONWASA's cross connection regulations require that all backflow prevention assemblies be tested annually by a certified tester. (Updated Dec. 2017)

Backflow Prevention Test and Maintenance Report