What Can Be Done to Prevent Contamination of Public Water Systems?
Modern technology has provided us with new tools to prevent backflow from non-potable sources into our public water systems. They are called backflow prevention assemblies. There are two types: reduced pressure (RP) or double check valve (DC) type.

Unlike the older accepted, non-testable, hardware for preventing backflow such as swing check valves, dual check valves, and atmospheric vacuum breakers (which still have their applications), the RP- and DC- type backflow prevention assemblies are testable to assure they are in proper working order.

Placed at the site of the cross-connection they can protect the plumbing system from contamination. Placed just downstream of a water meter to an establishment, they can protect the public water system from any contamination that may occur within the entire establishment's plumbing system.