Residents of Tilley, Alta., can drink water from the tap after a 3½-year boil-water order was lifted. (CBC)

For the first time in nearly four years, people in a village southeast of Calgary can safely drink straight from the tap after the province lifted a boil-water advisory.

Tilley, Alta. — population 405 — is now getting its water from the city of Brooks, 22 kilometres northwest, which has just completed a $45-million upgrade to its water treatment plant.

The improvements include a water transmission main to its smaller neighbours, provincial and village officials said Monday.

Residents of Tilley have had to boil their water since 2006 when Alberta Health Services told the village its water was not safe to drink.

Because of concerns about turbidity and bacteria found in water samples, the province decided Tilley's water treatment facility was no longer adequate and recommended the community tie in to an improved regional water system in Brooks.

The province covered $37 million of the project's cost, with Brooks and the County of Newell No. 4 paying the rest.

The village celebrated the return of clean tap water with a party at the village office Monday.

"It was a real treat to just brush my teeth with that good water," said resident Hubie Kallon.

Residents of Tilley had been forced to transport water to the village since the boil-water order was issued, said Mayor John Timko.

"Bottled water has been brought into the school for 3½ years — every business, including the stores, the hotel, the arena, the curling rink, the community centre," he said.

The newly upgraded plant also serves the hamlets of Lake Newell Resort, Rainer, Scandia, Rolling Hills and Patricia.