Officials Give All-Clear Signal for Tap Water at Edwards Air Base : Contamination: Air Force formally ends 2 1/2-day warning after test results show no problems.

More than 20,000 workers and residents at Edwards Air Force Base were told Friday afternoon they could resume drinking tap water there after a ground well failure had piped murky brown water throughout much of the base since Wednesday.

Air Force officials formally ended their 2 1/2-day warning after test results received Friday showed no problems with chemical or bacteriological contamination. Base officials also said the water had cleared of what they believe was sand and sediment.

“We feel very confident the water is fine,” said Lt. Col. John Shirtz, the director of bioengineering programs at the base. “The water is safe to drink.”

Edwards, the Air Force’s main flight test center, is about 90 miles northeast of downtown Los Angeles in the Antelope Valley.

Base officials were still trying to determine what went wrong with the ground water well, one of about a dozen that provide the entire drinking water supply for the base. Although the one well was not a major producer, officials said its loss alone could worsen the base’s water supply problems this summer.

“When the demand goes up, that’s when it will really hurt us,” said Bob Johnstone, a top civilian official at the base who deals with water supply. To conserve, the base already limits residents’ lawn watering to alternate days and forbids watering and car washing on Wednesdays.

Johnstone said further investigation next week on the cause of the well failure could be critical. Base officials hope the problem was caused by old age. But if it failed because of the sinking ground that has been a problem at the base, several other nearby wells could also be endangered, he said.

At the outset Wednesday, base residents and workers rushed to the commissary at Edwards and bought out its stock of bottled water, forcing officials there to order emergency truck supplies from the cities of Industry and Ontario that arrived later in the day.

“They were picking it up by three and four cases to six and eight cases at a time,” said Byron Borgaes, the base commissary officer. “My shelves were literally annihilated within the first 30 minutes I opened the store. We’ve never had that experience before.”

Borgaes said the base commissary normally sells several dozen cases of bottled water a day. Since Wednesday, he said, the commissary had sold about 10 times that amount.

By Friday afternoon, the demand had slacked considerably and the commissary had plenty of water on it shelves. But base residents still were being told to run their faucets once for about 15 minutes to help flush out any remaining sediment.