Pennsylvania American Water customers in Yardley, Lower Makefield, and parts of Falls Township no longer have to boil their water before use, the company said Tuesday in announcing an end to the warning issued four days ago.

“We have received acceptable test results showing no sign of bacteria in the water samples collected on December 2, and December 3, and the Pennsylvania Department of Environmental Protection has authorized lifting the advisory,” the company said in a statement.

The problem prompted the Pennsbury School District to close for the day Friday, but the district reopened Monday after American Water provided bottled water for the district’s eight schools.

The boil advisory was issued Thursday due to a spike in turbidity, or cloudiness, levels at the water treatment plant.

While the advisory has been lifted, customers are being advised to flush their pipes by running all cold-water faucets for at least five minutes simultaneously before using the water and to take the following additional steps:

  • Flush automatic ice makers by making three batches of ice and discarding them, then cleaning and sanitizing the ice bin.
  • Run water softeners through a regeneration cycle. Use the owner’s manual for instructions.
  • Change your refrigerator’s filter cartridge.
  • Run water coolers with direct connections for five minutes at the highest flow rate possible.
  • Drain and refill hot-water heaters set below 113 degrees Fahrenheit.
  • For home water filter systems, change filter cartridges. Some units will need to be disinfected.
  • Commercial customers should flush adequately to turn over the water in their plumbing systems, including flushing their automatic ice makers and drinking water fountains.

For more information, customers can contact Pennsylvania American Water’s customer service center at 800-565-7292.