Laboratory tests of water samples from six Montgomery County municipalities came back negative for bacteria Thursday, Pennsylvania American Water announced. Officials could lift a precautionary boil water advisory affecting the area as soon as Friday.
The advisory was put into place late Tuesday after parts of the Norristown-area water distribution system lost pressure. Depleted water levels increase the risk of elevated bacteria levels, officials said.
By Thursday, the Norristown Water Treatment Plant had returned to normal production levels and its storage tanks had refilled to near-normal capacity, according to the utility company.
Still, the boil water advisory remained in place for about 18,000 Pennsylvania American Water customers. The state Department of Environmental Protection requires two consecutive days of clean test results before a boil water advisory can be lifted.
Pennsylvania American Water collected a second set of samples Thursday. If those show no evidence of bacteria, the advisory could be lifted Friday.