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Protect Your Drinking Water from Backflow Contamination
Cross Connections - Backflow
The drinking water supply system can be contaminated if water from a customer’s building flows back into the water supply system.  This can occur if the water main pressure drops, or if the interior plumbing from a building is not properly installed.  This backflow occurs through a plumbing connection that is called a Cross-Connection.  (Definition from MDEP “Protecting Your Water” flyer - A Cross-Connection occurs whenever a potable water line is directly or indirectly linked to a piece of equipment or piping containing non-potable water.)  To avoid this possibility, the DPW administers the Cross-Connection Control Program.  Under this program, all commercial properties are routinely surveyed to be sure that special protective check valves are installed and maintained.  The Cross-Connection Control Program and the Plumbing Code help to insure that the risk from this form of system contamination is avoided.
Residential water customers also need to be aware of this risk and understand how to prevent backflow at their homes.  A backflow event can occur at a home as well as a business and can draw contaminants into YOUR water system, placing you and your family at the greatest risk.
The potential for backflow through a cross connection seems remote but the consequences are severe.  Cross connection backflow has the greatest potential for having your water contaminated to a degree that it can cause immediate illness or death.  Imagine taking a drink of water that is laced with pesticides or lawn chemicals.  

Some things you should do to prevent backflow at your home:
  • Have all changes to your plumbing system done by a licensed plumber.
  • Install and maintain hose bib vacuum breakers on all outside faucets.  (The hose bib vacuum breaker isolates your garden hose from the rest of your plumbing system.  Garden hoses are the most likely source of residential backflow.  Hoses left in a swimming pool, on the ground in a puddle, or connected to a lawn or garden chemical sprayer without a hose bid vacuum breaker creates a potential for water system contamination.)
  • Do not attach any pesticide, chemical, or any other non-potable liquid applicator to your water line.
  • Survey your home to make sure no hoses or pipes are connected to a potential source of contamination.  (Please contact the DPW (508-966-5813) or Plumbing Inspector (508-966-5821) if you have any questions about the plumbing at your house.  We will gladly perform a survey of your plumbing free of charge.)
Contact us to get more information about Cross-Connections and our program to prevent them, or for a copy of the MDEP “Protecting Your Water” Flyer.