Cross Contamination

YOU CAN AFFECT THE QUALITY OF THE WATER YOU DRINK

Many public drinking water systems are contaminated each year by pollutants or contaminants that back flow into the water system through unprotected cross-connections. Identifying and eliminating or protecting cross connections is a matter of public health. 

WHAT IS A CROSS-CONNECTION?

A cross-connection is a physical connection (piping configuration) between the public drinking water system and anything else, including another water supply that can allow pollutants or contaminants to back flow into the public drinking water system.

WHAT IS BACKFLOW?

Backflow is the reversal of the flow from a residential or commercial water system back into the public drinking water system. A back flow incident could carry pollutants or contaminants into our public drinking water supplies making them unsafe to use.

CAN I AVOID CROSS-CONNECTION AND BACKFLOW?

Yes! Several common cross connections are described in the following paragraphs.

Threaded Hose Connections (Hose Bibs)

A large majority of back flow incidents are created by the common garden hose.  Modern Plumbing Codes require that all threaded potable water outlets (hose bibs or sill cocks), except water heater drains and clothes washer connections, be protected by a non-removable hose bib vacuum breaker or an atmospheric vacuum breaker.  The installation of a hose bib vacuum breaker is an inexpensive way to protect against contamination.

Kitchen and Bathroom Faucets

Kitchen and bathroom facets are generally designed with an adequate air gap between the end of the faucet and the flood rim of the sink.  They are manufactured so that a hose can not be attached to the end of the faucet.  Slip on hose connections can defeat the protection of the air gap and should not be used.

Hand held shower sprayers and other similar hose attachments also pose a problem.  If submerged in the water, back-siphonage can occur.  This problem can be corrected by installing a special hose vacuum breaker.

Laundry Rooms

Your washing machine has air gaps built in at the factory.  Utility sink faucets must be equipped with a hose bib vacuum breaker or atmospheric vacuum breaker.

Special Conditions

Drain lines from water softeners and water conditioners are typically connected to the sewer line.  An air gap must be provided between the end of the drain line and the sewer line to eliminate the possibility of raw sewage being back-siphoned into the drinking water system.

Sinks used for special purposes such as home photography darkrooms, arts and crafts, etc.  must be protected by vacuum breakers to ensure that chemicals or other pollutants will not enter the water supply.

Ballcock Assemblies in Toilets

Many toilets are equipped with ballcock assemblies that do not meet code. These assemblies can allow water from the toilet tank to be siphoned back into the drinking water supply.  Anti-siphon ballcock assemblies must be used to protect against back-siphonage.

Landscape Sprinkling System 

The Plumbing Code requires that all landscape sprinkling systems connected to the public drinking water system be equipped with an approved back flow prevention device or assembly.

Any sprinkling system that can utilize both public drinking water supplies and secondary water supplies must follow specific plumbing regulations to prevent raw water from entering the drinking water system!

WHERE CAN I GET INFORMATION OR HAVE MY QUESTIONS ABOUT CROSS CONNECTIONS ANSWERED?

Call your local plumbing inspector or call the office at 435-644-3997 regarding cross connection control and back flow prevention requirements in your specific area.

For further information call:

Utah Chapter – American Backflow Prevention Association – 801-949-5512

Utah State Division of Drinking Water – 801-536-4200