What is a backflow preventer?

A backflow preventer is a mechanical or automatic valve that allows water to flow in one direction only, preventing contaminated water from reversing course and entering your home's or business's drinking water line. Backflow occurs when pressure changes cause water to flow backward through pipes, potentially carrying chemical, biological, or physical contaminants from appliances, irrigation systems, or commercial processes into the main water supply.

Connecticut plumbing code requires annual testing and certification of backflow preventers on certain connections where cross-contamination risk is high. These typically include irrigation systems, boiler systems, lawn sprinkler networks, and commercial buildings with on-site water treatment or auxiliary water sources. Residential single-family homes may need them in specific situations, particularly if they have in-ground irrigation.

Common installation points are at the meter or service entrance, on lawn irrigation lines, on water lines serving boilers or hot water tanks, and at any point where non-potable water could enter the public system. Different types include atmospheric vacuum breakers for low-hazard applications and reduced pressure principle (RPP) devices for high-hazard situations. Many Greater Hartford property owners rely on local plumbers to install these devices correctly and maintain the required annual testing documentation to stay compliant with state codes.