Frequently Asked Questions

A cross-connection is any actual or potential physical connection or arrangement between a pipe conveying potable water from a public water system and any non-potable water supply, piping arrangement or equipment including, but not limited to, waste pipe, soil pipe, sewer, drain, other unapproved sources.

An airgap is an unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture, or other device and the flood level rim of the receptacle. This separation must be at least twice the internal diameter of the water supply pipe and never less than one inch. An air gap is considered the maximum protection available against backpressure backflow or back-siphonage but is not always practical and can easily be bypassed.

A reduced pressure zone assembly is an approved testable backflow prevention device incorporating: 2 or more check valves; an automatically operating differential relief valve located between the 2 checks; 2 shut-off valves; and necessary appurtenances for testing. A sprinkler and irrigation system that has a chemical feed requires this device. It is also commonly used in commercial establishments to protect against numerous contaminants. These devices must be installed above ground.

A double-check valve assembly is a testable backflow prevention device that incorporates an assembly of check valves, with shut-off valves at each end and appurtenances for testing. For instance, sprinkler and irrigation systems are required to be protected by these devices. They are normally installed near the meter in an underground box.

An atmospheric vacuum breaker is an approved backflow prevention device used to prevent back siphonage which is not designed for use under static line pressure.

A pressure vacuum breaker is an approved backflow prevention device designed to prevent only back siphonage and which is designed for use under static line pressure.

A hose bibb vacuum breaker (HBVB) is one of the least expensive and most commonly used backflow preventers. When attached to an outside water tap, these backflow preventers keep water that may be contaminated with fertilizer or insecticide from entering your drinking water. You should attach an HBVB if you have a sprayer on your hose.

In order to insure the proper operation of a backlfow assembly, it must be tested and certified upon installation and periodically thereafter as required by state code. If the hazard (substance you are protecting against) is considered a high hazard (i.e., a hazard that can cause health problems), the State requires that the device be tested twice a year. If the hazard is considered a low hazard (such as the hazard effects only the taste and odor of the water), the State requires testing once a year.