The function of a backflow prevention device is to prevent dirty water from storm drains, sewer lines, pools, spas, fire suppression systems, and irrigation lines from flowing backward or into the clean, uncontaminated, drinking water (potable water) in homes.

In California, every city and/or county has a law requiring backflow devices and annual testing by a licensed plumber certified to perform such work. The Company should arrange to have such testing completed timely in order to help assure that the supply of water remains clean. Most companies that perform this type of work will send annual reminders, but there is never an assurance that this will happen making it important for the manager to calendar the required annual inspection.