Cross-Connection Control Program


  1. To protect the public water supply served by the Town of Tewksbury from the possibility of contamination or pollution through backflow into the public water system from the Owner's internal distribution system.
  2. To promote control of or the elimination of existing cross-connections, actual or potential, between the in-plant potable water system and non-potable systems.
  3. To provide continuing maintenance of the cross-connection control program; effectively preventing the contamination or pollution of all potable water systems by cross-connection.


The Federal Safe Drinking Water Act requires that the water purveyor hold the primary responsibility for preventing water from unapproved sources, or any other substances, from entering the potable, public water system. This intent is further clarified in the Massachusetts DEP Cross-Connection Control Program Regulations, 310 CMR 22.22. In addition, authority arises from the rules and regulations published by the Massachusetts Board of State Examiners of Plumbers and Gasfitters, 248 CMR 176, sub-section 10.14.

Total Containment Policy: Tewksbury uses a Total Containment Policy which requires all Commercial, Industrial, Municipal and Institutional properties to install a Reduced Pressure Backflow Preventer at the meter.

Town of Tewksbury Forms & Bylaws

Types of Backflow Preventers
Air Gap (AG): A physical separation sufficient to prevent backflow between the free-flowing discharge end of the potable water system and any other system. Physically defined as a vertical distance equal to twice the diameter of the supply-side pipe diameter, however, no less than one inch.

Double check valve (DCVA) backflow prevention system
Atmospheric Vacuum Breaker (AVB): A device that prevents back-siphonage by creating an atmospheric vent when there is either negative pressure or sub-atmospheric pressure in a water system
Atmospheric vacuum breaker (AVB) backflow prevention system
Double Check Valve Assembly (DCVA): An assembly of two independently operating check valves with tightly closing shut-off valves on each side of the check valves, plus properly located test cocks for testing each check valve.

Double check valve assembly
Pressure Vacuum Breaker (PVB): A device containing one or two independently operated check valves and an independently operated spring-loaded air inlet valve located on the discharge side of the check valve(s). The device includes tightly closing shut-off valves on each side of the check valve(s) and properly located test cocks for the testing of the check valve(s).

Pressure vacuum breaker (PVB) backflow prevention system
Backflow Preventer with Intermediate Atmospheric Vent (BPIAV): A device having two independently operating check valves separated by an atmospheric vent chamber.Double check valve with atmospheric vent (BPIAV) backflow prevention system
Hose Bibb Vacuum Breaker: A device connected to a hose bibb acting as an Atmospheric Vacuum Breaker; this device is not to be used under constant pressure.
Hose bibb vacuum breaker backflow prevention system
Residential Dual Check: An assembly of two loaded, independently operating check valves without tightly closing shut-off valves and test cocks. Generally employed immediately downstream of the water meter to act as a containment device.

Residential dual check backflow prevention system

Reduced Pressure Backflow Preventer (RPBP): An assembly consisting of two independently operating check valves with an automatically operating differential relief valve located between the two check valves, tightly closing shut-off valves on each side of the check valves, plus properly located test cocks for the testing of the check.

Reduced pressure zone backflow preventer (RPBP) backflow prevention system
Barometric Loop: A fabricated piping arrangement rising at least thirty-five (35) feet at its topmost point above the highest fixture it supplies. It is utilized in water supply systems to protect against back-siphonage.
Barometric Loop backflow prevention system