Backflow preventers are the main way that it is guaranteed that any public water that enters your home does not return back to the public water supply to go to someone else's home. This is to make sure that all of the water that enters your home (and everyone else's home) is fresh and has been nowhere else. Your backflow preventer must be tested every year by a certified tester to assure that they are working properly.
Backflow preventers and backflow prevention test kits are available from www.supplyhouse.com
