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Sunday, November 29, 2020

Cross-Connection and Backflow Prevention

Cross-connections are any unprotected actual or potential connections between a public or a consumer’s potable water system and any other source through which it is possible to introduce any substance other than the intended potable water.

Cross-connections that contaminate drinking water distribution lines are a major concern.  A cross-connection is formed at any point where a drinking water line connects to equipment, systems containing chemicals (air conditioning systems, fire sprinkler systems, irrigation systems), or water sources of questionable quality.  Cross-connection contamination can occur when the pressure in the equipment or system is greater than the pressure inside the drinking water line (backpressure).  Contamination can also occur when the pressure in the drinking water line drops due to fairly routine occurrences (main breaks, heavy water demand), causing contaminants to be sucked out from the equipment and into the drinking water line (backsiphonage).

Backflow is the undesirable reversal of flow of water or mixtures of water and other liquids into the distribution pipes of the potable supply of water from any source.  Bypass arrangements, jumper connections or any other temporary or permanent connections through which backflow can occur are considered to be cross-connections, and are illegal.

Protection against backflow is provided by a variety of backflow prevention devices (BFPs) which are selected according to the potential hazard.

All backflow prevention assemblies (BFPs) must be tested upon installation and certified to be operating within specifications.  Backflow prevention assemblies which are installed to provide protection against health hazards must also be tested and certified to be operating within specifications at least annually by a recognized backflow prevention assembly tester.

A Test Report must be completed by the certified backflow prevention assembly tester for each assembly tested.  The signed and dated original must be submitted to the District for record keeping purposes.

Backflow prevention assembly testers must be qualified to test and repair assemblies on any domestic, commercial, industrial or irrigation service.  Backflow prevention assembly testers may test and repair assemblies on firelines only if there are permanently employed by an approved fireline contractor.  The State Fire Marshall’s office requires that any person performing maintenance on firelines must be employed by an approved fireline contractor.

If your system has a high hazard BFP installed for health hazard protection, the District will mail a letter annually listing the devices that must be tested.  You will have 30 days to get the BFP tested and repaired (if needed) and test results faxed to our office at (512) 266-2790.  A list of certified testers will be included for your convenience.