A qualified professional in your jurisdiction will utilize a backflow preventer test kit. The backflow preventer test kit is a compact portable device that measures differential pressure and is used for all testing of backflow prevention assemblies (DCVA, RP, PVB and SVB types). Depending on the model, test kits come equipped with either 3 or 5 soft seated needle valves. Equipped with a full-face scale, the kit can measure a range of 0-15 psid (psi differential). Test kits are equipped with three color-coded service hoses with inline filters for connecting the test kit to the backflow prevention assembly.
Manufacturers of backflow assemblies and most regulating authorities require annual testing to ensure the assembly is functioning properly. Backflow assemblies are mechanical devices. Just like car maintenance with regular oil changes, a backflow assembly must be checked to ensure it functions properly.