Repeat tests find no issues with bacteria

Photo Credit: PIONEER ILLUSTRATION - Deschutes Valley Water District sent out notification letters to district patrons after two samples tested positive for bacteria. The district repeated the tests twice, and the tests came back clean, but the district is required to send out letters.For a short time last week, Deschutes Valley Water District was on high alert, when routine water samples came back showing the presence of bacteria.

Fortunately, two sets of repeated tests came back clean, and Friday afternoon, Ed Pugh, district manager, was relieved to learn that a letter of notification to district patrons was all that was required.

The alert started on Aug. 5, when DVWD personnel took five routine water samples and two of the samples tested positive for bacteria: one for total coliform, and the other for E. coli. The samples were from locations in the Southwest LaSalle and Jericho Lane area on the south end of the district.

Total coliform indicates the presence of bacteria that might be found in the soil, in water that has been affected by surface water, or in human or animal waste, while E. coli is bacteria from the intestines of people or animals.

The district immediately notified the water bottling companies — which took their own samples and found no contamination — and took new samples, which also came back clean.

"We have no idea where that came from," said Pugh, who personally examined all the district's tanks, crawling on top of the enclosed tanks to check them out.

Even though they didn't find anything, he ordered flushing of the main tanks and chlorination from the Metolius tank north, since the district's water flows north. The district avoided chlorinating the tanks on the south half of the district since it would have affected the water bottling companies, which had not found contamination.

Pugh speculated that a bird or other small animal could have gotten into a vent on a tank — which doesn't seem to have been the case — or it could have been a testing anomaly.

After retesting and not finding evidence of contamination, the district took nine additional samples: one at each of the locations where the bad tests had occurred, as well as samples from a residence upstream and downstream from each of those sites, and then three samples from the main source.

"Thankfully, all nine repeat samples were good," he said Friday afternoon. The district is required by the Oregon Health Authority to send out notification to district patrons within 30 days, but DVWD expected to send out the letters early this week.

The last time the district had an incident was about five years ago, in the winter, he recalled. "We had to do the notification, but didn't have to boil water," he said.

That incident was right after the district had shut down a 20-inch line, which could have caused the problem, he said.

"When you have a nonchlorinated system, you're more at risk of having an incident, but if we can keep a really good record of not very many incidences, we can keep our status as a nonchlorinated system," he said.

The district, formed in 1919, has won numerous awards for the purity and taste of the water, which flows out of Opal Springs. Last year, it was judged the best overall water in Oregon.

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