Backflow Prevention and Cross Connection

The Hanover Water Department makes every effort to ensure that the water delivered to your home and business is clean, safe, and free of contamination.  But what happens when the water reaches your home or business?  There is still a need to protect the water quality from contamination caused by a cross-connection.

What is a Cross-Connection?

A cross-connection occurs whenever the drinking water supply is or could be in contact with potential sources of pollution or contamination.  Cross-connections exist in piping arrangements or equipments that allow the drinking water to come in contact with non-potable liquids, solids, or gases (hazardous to humans) in event of a backflow.

Where Can Cross-Connections Occur?

Cross connections can occur at many points throughout a distribution system and a community's plumbing infrastructure. Cross connections can be identitifed by looking for physical interconnections between a customer's plumbing and the water system. Some specific examples of backflow incidents that can occur are:

• Lawn chemicals backflowing (backsiphoning) through a garden hose into indoor plumbing and potentially into the distribution system.
• Backsiphonage of "blue water" from a toilet into a building's water supply.
• Carbonated water from a restaurant's soda dispenser entering a water system due to backpressure.
• Backsiphonage of chemicals from industrial buildings into distribution system mains. 
• Backflow of boiler corrosion control chemicals into an office building's water supply.

What Can You Do to Prevent a Cross-Connection

Without the proper protection something as simple as a garden hose has the potential to contaminate or pollute the drinking water lines in your house. In fact, over half of the country’s cross-connection incidents involve unprotected garden hoses. There are very simple steps that you, as a drinking water user, can take to prevent such hazards:

• Never submerge a hose in soapy water buckets, pet watering containers, pool, tubs, sinks, drains, or chemicals.
• Never attached a hose to a garden sprayer without the proper backflow preventer.
• Buy and install a hose bib vacuum breaker on every threaded water fixture.  The installation can be as easy as attaching a garden hose to a spigot.  This inexpensive device is available at most hardware stores and home-improvement centers.
• Identify and be aware of potential cross-connections to your water line.
• Buy appliances and equipment with a backflow preventer.
• Buy and install backflow prevention devices or assemblies for all high and moderate hazard connections.

If you are the owner or manager of a property that is being used as a commercial, industrial, or institutional facility you must have your property’s plumbing system surveyed for cross-connection.  If your property has NOT been surveyed for cross-connection, contact this office at 781-826-3189 to schedule a cross-connection survey.

The Massachusetts Drinking Water Regulations, 310 CMR 22.00, requires all public water systems to have an approved and fully implemented Cross-Connection Control Program (CCCP). The Hanover Water Department is working diligently to protect the public health of its drinking water customers from the hazards caused by unprotected cross-connections.  We are doing this through the implementation of our cross-connection survey program, elimination or proper protection of all identified cross-connections, the registration of all cross-connections protected by reduced pressure backflow preventers (RPs) or double check valve assemblies (DCs), and the implementation of a testing program for all RPs and DCs.

Annual Backflow Test Summary

Annual Cross Connection Survey Summary