AgdaPkt 2013-01-14 - Laserfiche WebLink

Browse Search

7.A. - Page 2 and the public health. Type of backflow devises include: (1) an air gap separator, which is considered the maximum protection available against backflow; (2) reduced pressure principle backflow assembly (RP), which is effective against backpressure backflow and back-siphonage and may be used to isolate health or non-health hazards; and (3) a double check valve assembly (DC) which is also effective but more commonly used when there is a need to isolate only non-health hazards and is generally preferred to be above grade for ease of testing and performing maintenance, although they can be installed below grade if installed with a proper vault. In any case, the backflow preventers need to be tested periodically because they are subject to fouling, wear, or fatigue. In addition, most public agencies require that the assembly be installed at the meter because this is the best location in order to prevent additional cross connections and also to prevent disruption to private property when the City needs to access the device. In compliance with state law (Title 17, California Code of Regulations, California Department of Public Health), in 2008, the City adopted a cross-connection control program contained in Article VII of Chapter 38 of the City's Municipal Code. The ordinance required that any property with an auxiliary water source install, at the owner's expense, an approved backflow prevention assembly in the service line as close to the City water system terminal as possible, with the type of assembly dependent upon the hazard, annual tests by an approved tester required, and an administrative fee of $60 to be charged per backflow device for costs of administering the program. Penalties for violations included termination of water service and criminal prosecution. On September 16, 2011, a cross-connection occurred at a residence in Redwood City. The City issued a "boil tap water" advisory to approximately 300 residences and businesses due to possible contamination of the City's water system within a certain radius. The City has used multiple methods of notifying the affected area, including its CodeRED emergency phone/email/text messaging system, and written notices posted at each property. The property had un-permitted well and which had been inadvertently pumping untreated well water into the City's drinking water system for approximately two weeks, when the resident had some plumbing work performed on his water system. An estimated 75,000 gallons of non-potable well water was injected into the City's water system. Upon discovery, the City immediately disconnected the well water system from its drinking water system, and commenced "flushing" the City's water system in that area through fire hydrants in order to purge any remaining non-potable water. However, until all the property tests could be completed — including tested for coliform bacteria and E. Coli — residents had to boil water to protect themselves, and in particular, protect susceptible populations like infants, the elderly, and anyone with a compromised immune systems. As a result of the cross-connection incident, the State of California required that the City create a Corrective Action Plan, which was submitted to the State in November 2011, to Page 2 of 6