Dallas flushes out water after finding coliform

Neither the bacteria nor the treatment are harmful to humans

DALLAS -- Dallas officials tested the waters -- and found coliform bacteria.

Dallas water users might have noticed their tap water smelling like a swimming pool last weekend. City officials flushed the system with more chlorine than usual after discovering the harmless organisms.

The chlorine level stayed well within limits for all use, including drinking, said Dave Leland, drinking water program manager with the state Health Division.

Dallas tested positive for coliform bacteria throughout the water system. The bacteria, though not harmful to humans, show the possibility of disease-causing pollutants in the water.

No E. coli or fecal coliform were found in Dallas' water supply. Coliform from animal waste can point to the presence of giardia or cryptosporidium in the water, Leland said.

At that point, health officials recommend boiling water. There is no need to boil Dallas water, Leland said.

The positive tests in Dallas came from a film forming on top of water-holding tanks, said City Manager Roger Jordan. These tanks have been cut off from the water system for cleaning.

Subsequent tests proved negative, Jordan said, but the results of the treatment won't be known for sure until later this week.

Dallas water returned to its normal chlorine level by Aug. 5, Jordan said.

Coliforms don't mean Dallas' water treatment is inadequate, Leland said. "No treatment system on the planet is 100 percent effective.

"Drinking water is not completely sterile."

Dallas tests its water more than 15 times a month, Leland said. The coliform just alerts officials to stay watchful. "This is our alarm system."

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