Seven towns in Bergen County are under a boil water advisory after E. coli was detected within a water distribution system following a water main break.

Fairview, Cliffside Park, Ridgefield, Edgewater, Fort Lee, Palisades Park and Leonia were notified by Veolia Water New Jersey after 9 p.m. on Thursday after test results returned.

The boil water advisory remains in effect. New water samples will be collected on Saturday morning, for testing by the NJ Department of Environmental Protection & Energy, according to a message sent out to Leonia residents. The earliest that the boil water advisory might be lifted would be Sunday afternoon.

Residents are also reminded that Veolia does not recommend the use of water filters during the boil water advisory and that they will not be effective.

Additional water tests were performed after a water main break occurred in Ridgefield on Monday night during a rainstorm. The water main break wasn't fully repaired until Tuesday followed by additional water tests.

Veolia, formerly Suez Water, takes over 7,000 water quality tests a month normally, Debra Vial, a spokeswoman for Veolia said. Additional tests came back clear Tuesday, but it takes 24 hours for the E. coli test to return. After a trace amount of E. coli returned, the state required the company to validate the results with additional tests, which came back Thursday night.

"One of the many tests indicated a trace amount, which triggered a boil water before drinking advisory," Vial said.

E. coli indicates that water may be contaminated with human or animal wastes. "Human pathogens in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms," Veolia warned. "They may pose a greater health risk for infants, young children, the elderly, and people with severely compromised immune systems."

Bacterial contamination can occur when increased run-off enters the drinking water source, like during the heavy rains earlier this week. It can also happen due to a break in the distribution system pipes or a failure in the water treatment process.

Additional test results are scheduled to return Friday night and if needed Saturday that will determine when the advisory will be lifted.

Veolia began flushing all the pipes in the area with high velocity water to clear the E. coli. Phone messages were sent to customers and town officials were notified and began issuing their own warnings to residents. The same notification process will take place once clean test results are received.

Tens of thousands of water bottles were distributed to the effected towns in senior housing areas. A water tanker is also available on Brinkerhoff Avenue in Fort Lee.

Do not drink the water.

Residents are instructed to bring tap water, even if it is filtered, to a rolling boil for one minute and allow it to cool before using for the following: drinking, cooking, or baking, making ice cubes, taking medication, brushing teeth, handwashing dishes, washing food, mixing baby formula or food, mixing juices or drinks, feeding pets, and all other consumption. Boiling kills bacteria and other organisms that may be present in the water.  Water does not have to be boiled for showering or washing clothes.

After a notice has been lifted, you should flush household pipes, ice makers, water fountains, etc., prior to using for drinking or cooking. Flushing simply means letting the water run to ensure that no contaminated water remains in your pipes. Follow these guidelines for flushing: