Why do I need a backflow preventer?

MIC Cross-Connection Control and Backflow Prevention Program

There are two types of backflow conditions, which could contaminate the public water system: backsiphonage and backpressure.

1. Backsiphonage occurs when the supply pressure at the water meter decreases below the pressure on the consumer's side. This could be caused by a water main break, water system repairs, or large fire demands. Water is siphoned into the public system, possibly drawing hazardous substances into the drinking water system.

2. Backpressure occurs when the consumer-side pressure overcomes the normal supply pressure. This can be caused by the operation of a boiler or a separate booster pump system connected to the consumer piping. In essence, contaminated water is "pumped" back into the drinking water system.

Unlawful connection caused water warning

By The Garden Island | Friday, May 27, 2011, 11:30 p.m.

KILAUEA — A “do not use” advisory in Kilauea last week was caused by an unlawful cross connection that was installed by a Department of Water customer in Kilauea, a county press released stated.

The cross connection was caused by the customer connecting a surface water irrigation line to the water system without an approved backflow preventer. When the pressure in the irrigation line increased, irrigation water was pushed into the county water system, causing the contamination, according to the release.

“We want to assure our customers that we have taken immediate action to mitigate the chances of similar incidents from occurring again,” Deputy Manager-Engineer William Eddy said in the release.

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After receiving reports of the dirty water, DOW staff investigated and found the cross connection with surface water on private property on May 19. Upon finding the unauthorized cross connection, crews pulled the meter from that property, thereby disconnecting that customer from the water system.

DOW staff took samples, which came up positive for ecoli. DOW proceeded to flush the entire system until there was no turbid water and disinfection residuals were up to standard. 

The DOW issued a “do not use” notice on radio, television and through the Kaua‘i County Connect CTY notification system advising residents in the area not to use the water for consumption. The “do not use” advisory was downgraded to a “boil water” advisory on May 20 after disinfection residuals were up to standard.

The boil water advisory was canceled on May 21 when laboratory tests on all water samples taken after flushing the entire water system late in the evening on May 19 indicated that it was safe and free of contamination.

“We would like to take this opportunity to explain how dangerous this type of activity can be,” DOW Manager and Chief Engineer David Craddick said in the release. “Cutting into the potable water system can result in both criminal and civil penalties.”

Craddick said: “Everyone in the community needs to take an active role in helping to protect the water that is provided for our families, friends and neighbors.”

The DOW Rules and Regulations, Part 3, Section XX, states: No cross-connections with other water supplies, or other physical connections, shall exist, or be installed, located, maintained or operated which could permit backflow of contaminated water, except in situations where there is adequate protection against backflow.

Cross connections include connecting the public water system before or after the meter to any system that can hold water such as pools, tanks, irrigation systems or extra-long pipelines and pumps, which also includes opening or connecting to hydrants illegally. These types of systems require an authorized backflow preventer.

The county encourages residents to log onto www.kauai.gov to register with the Connect CTY notifications system.

The DOW apologizes for any inconvenience and thanks its Kilauea customers for their patience and understanding, the release stated.

Go to www.kauaiwater.org for more information or call DOW at 245-5455. For emergencies after business hours, call Police Dispatch at 241-1711.