PARK CITY — Some Park City residents were told Thursday afternoon they don't have to boil their water anymore.

But the search continued for whoever tampered with the town's water tank.

Wednesday, Park City Municipal Corp. issued a boil-water alert for more than 115 homes served by the Quarry Mountain Water Tank. That followed the discovery Monday that the hatch of the water tank had been opened and the lock cut, said city spokeswoman Phyllis Robinson.

Not knowing whether the water had been tampered with, the boil alert was issued about 5 p.m. Tuesday as a precaution. About 3 p.m. Thursday, test results were completed showing no contamination, she said.

The city is offering a $1,000 reward for information leading to the arrest and conviction of the person responsible.

Robinson said investigators weren't sure Thursday if the cut lock was a prank or if someone was actually trying to sabotage the water supply. But she noted the water tank is in a "pretty remote area."

"You have to work to get there," she said.

Tampering with the water tank is a federal crime and could be punishable by up to 20 years in federal prison and a $1 million fine if convicted, she said.

The city provided affected residents with free bottled water.

Anyone with information on the incident can call police at 435-615-5500.