Cross Connection and Backflow Device Inspection



There are laws that apply to cross connections. The Massachusetts Plumbing Code (248 CMR 2.14) and Massachusetts Drinking Water Regulations (310 CMR 22.22) both require installation of backflow preventers at all cross connections. In addition, backflow preventers at cross connections are to be inspected once a year by a certified backflow preventer inspector. Your local public water supplier is also required by DEP to inspect cross connections twice a year.  Please contact our Department at 508-432-0304 if you have a backflow device that needs testing.

Backflow Preventer Diagram


Cross Connection & Contamination

Cross connections which could contaminate drinking water distribution lines are a major concern of the Department of Environmental Protection (DEP). A “cross connection” is formed at any point where a drinking water line connects to any equipment or system containing chemicals or water of questionable quality. Cross connections can occur at:

Community drinking water distribution systems, as well as internal facility drinking water systems, are continuously jeopardized by cross connections unless appropriate valves, known as backflow prevention devices, are installed and maintained. As an owner of one or more cross connections you have the responsibility to maintain the system so that drinking water in your facility or the surrounding neighborhood is not contaminated. Serious illness, even deaths, have been caused by “backflow” contamination-incidents that could have been prevented.

How Backflow Occurs

Water of questionable quality or chemicals used in a system or equipment can end up in the drinking water line as a result of “back-pressure” or “backsiphonage”. Back-pressure occurs when the pressure in the equipment or system (A/C, boiler, etc.) is greater than the pressure in the drinking water line. Backsiphonage occurs when the pressure in the drinking water line drops (main breaks, fires, heavy demand) and contaminants are sucked out of the system into the drinking water line.

Please contact our Department at 508-432-0304 if you have a backflow device that needs testing.