By Bruce Rathburn
The Importance of Backflow Prevention
ackflow incidents occur daily in the U.S., although known or believed to have occurred in numerous recent these incidents typically only affect a single house- incidents.
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hold. There are millions of opportunities to create cross-connections, which could result in backflow inci- Boise, Idaho dents. Over Memorial Day Weekend 2012, as many as 80 resi- For example, inspectors at Pinellas County Utilities in dents in Boise, Idaho, got sick from bacteria that apparent- Florida discovered several cross-connections in homes in ly came from the drinking water. When a water meter early February. The possibility of more incidents all over showed unusual readings, further inspection discovered that the U.S. increases when there are piping mistakes, unli- an empty house in the Hobble Creek neighborhood was the censed contractors, incorrect plumbing, unregulated manu- location of the problem. An installed backflow preventer facturers, and careless connections to irrigation systems and failed to keep irrigation water out of the drinking water sys- retention ponds. tem. The backflow preventer had not been inspected regu- While certain cross-connections will not result in illness- larly, according to the Idaho Statesman . es from consuming contaminated drinking water, other A spokesman for the Boise water system explained to cross-connections are likely to cause people to get sick. reporters that ultimately the responsibility for keeping irri- Therefore, as noted in the ABPA position statement on gation water out of the drinking water system does not cross-connections and appropriate backflow protection, the belong to the water company. Instead, state law requires actual or potential degree of the health hazard determines customers to have proper backflow devices installed, which how cross-connections are classified. Classifications are: must be tested annually. Property owners are responsible low hazard (because health problems will not be caused) or for maintaining these critical public safety devices. Boise high hazard (because of the potential to cause human illness State Public Radio reported this incident. or possible death). Once the degree of hazard and type of backflow is determined, you can look to a list of approved Louisiana assemblies. The list of approved assemblies is usually Sometimes contamination only begins in a small area. In established by the administrative authority that has jurisdic- 2012, people from a neighborhood in Louisiana fell ill with tion. bacterial infections from micro-organisms that entered The different types of backflow assemblies have certain drinking water through a garden hose left in a large above- applications as to how they can be installed. It is important ground swimming pool. The homeowner noticed the hose that they only be installed in the same orientation and type siphoning water, but they did not think there was a problem, of protection as determined by the approval agency. One of because the hose would only be turned on when the pool the most recognized approval agencies, the USC was in use, and it was not operated all the time. The Foundation for Cross Connection Control & Hydraulic Louisiana Department of Health and Hospitals recorded Research (USC FCCC-HR), is one of the only approval or this incident. listing agencies that requires a lab and field evaluation prior to an assembly being approved for listing. The foundation Denver, Colorado publishes a List of Approved Assemblies that contains the Even contamination for one home can be serious. In model, size and orientation that each assembly is approved 2012, a family living outside Denver, Colo., was awarded in. Most administrative authorities having jurisdiction use nearly $1 million in damages after drinking water contami- the list provided by the foundation. nated with raw sewage. High-hazard cross-connections and backflow were
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Page 62/Plumbing Engineer October 20013
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