Most backflow devices do not need to be tested or are not testable. However, two types of devices used to protect connections that pose the highest hazards need to be tested regularly.

Double Check Valve Assemblies (DCVA) are typically found on fire protection systems that are made of non-potable materials and have a fire truck connection. These devices prevent contaminated water from being drawn into the distribution system during main breaks or water being forced into the distribution system if the Fire Department uses the truck connection. DCVAs need to be tested on an annual basis.

Reduced Pressure Backflow Preventer (RP) are found on the highest hazard connections. These devices are designed to protect the water system even if part of the device fails. They are found on connections that a high risk such as chemical mixing tanks, heating systems containing chemical additives, fire protection systems with chemical additives and x-ray developers. RPs are tested once every six months.

Testing these devices ensures they are being maintained and in proper working order. The owner of the device has 14 days to repair or replace a device that has failed a test.