A precautionary order to boil water in Round Lake Beach is expected to continue until Thursday afternoon.
Village officials issued the order Wednesday after pressure in the system dropped when a water flow regulator failed.
Public Works Director Keith Neitzke said nothing entered the system but the order is required under state protocol.
"We dropped pressure. It wasn't overly significant but it was in the range we needed to respond," he said.
The order to boil all water used for cooking or drinking will remain in effect until results of testing on samples are received, he added.
Round Lake Beach water users should boil water vigorously for five minutes before use for cooking or drinking; and, disinfect dishes by immersing them for at least one minute in clean tap water that contains one teaspoon of unscented household bleach per gallon of water.
When water pressure is low, conditions exist that could allow contamination to enter the distribution system.
"The system maintained its integrity," Neitzke said.
Anyone with questions should call (847) 546-8752.