The state Department of Environmental Protection had ordered the testing after it said the Water Department failed over three years to consistently use a soda ash additive to adjust the water's pH to prevent corrision. The additive is designed to adjust the pH to 7 or higher
Officials say the city's water is safe, but residents with compromised immune systems are still being cautioned after three water samples came up positive for total coliform bacteria.
According to a letter mailed to residents from the Water Department, random testing in June turned up positive samples of coliform bacteria. However, the department says samples taken from the same sites the next day came up negative.