KINGMAN - Throughout April, city water customers received notices with their bills explaining that four routine water samples taken in March came up positive for coliform bacteria.
According to the notice, the situation was not an emergency. That's why customers were notified throughout April and not all at once.
City Water Superintendent George Sedich said that had it been an emergency, the city would have notified the community via radio, newspaper and mail.
The city takes 50 water samples a month from different distribution points and over a period of a couple weeks, Sedich said. When a given week is extra windy and dusty, the city generally schedules tests for the following week. Dirt and dust contain a lot of impurities, Sedich said, and can lead to total coliforms getting into the water system.
According to the Environmental Protection Agency, total coliforms are a group of closely related, mostly harmless bacteria that live in soil and water as well as in the gut of animals. The extent to which total coliforms are present in source water can indicate the general quality of the water, and the likelihood that the water is contaminated.
Total coliforms are currently controlled in drinking water regulations because their presence above the standard indicates problems in treatment or in the distribution system. EPA requires that all public water systems monitor for total coliforms in distribution systems. If total coliforms are found, then the public water system must further analyze the total coliform-positive sample to determine if specific types of coliforms, such as fecal coliform and E. coli are present.
Once the four-of-50 samples came up positive for the bacteria, Sedich said repeat samples were taken at each of the coliform-positive sites as well as upstream and downstream from the sites. Although those repeat samples came up positive for total coliforms, follow-up testing came up negative for fecal coliform and E. coli.
According to the notification water customers received, the city performed "extensive flushing and re-chlorination of the distribution system." Sample results taken after that came up negative for total coliforms.
Tests conducted for April came up negative as well, Sedich said.
Sedich suspects the bacteria entered the system during a period where maintenance was conducted downtown. He admits that it's an assumption, but added that he thinks the lines were not flushed adequately after the work was done.
Sedich has been the city's water superintendent for six years. He said it's the first time something like this has happened on his watch.
Although total coliforms are - for the most part - harmless, it is their presence in water that points to the possibility of other, more harmful, forms of bacteria being present. But that was not the case here, Sedich said.