ALPINE, Calif. - A water main break on Alpine Boulevard Friday prompted state authorities to issue a boil water advisory for most of the homes and businesses in Alpine, effective through at least Sunday.

The Padre Dam Municipal Water District said a 16-inch pipe broke at 4 p.m. Friday, and possible water contamination was a worry for Alpine customers east of Harbison Canyon Road.

People were urged to use only bottled water to drink or cook, or boil their tap water for one minute, then let it cool, before using it.

Boiling water kills bacteria and other harmful organisms.

"The total number of water accounts affected is 1,921, probably close to 5,000 people," said Melissa McChesney, the Padre Dam Municipal Water District communications officer.

McChesney said boil water orders are not uncommon because of the mountainous topography of the rural area.

 "Alpine is at such a high elevation, and there are a lot of elevation changes, so water main breaks depressurize the system," she said. "The majority of the time there ends up being a boil-water notice. It's
precautionary, and what the state requires."

Affected residents will be informed when tests show tap water is again safe to drink in their area, expected within 72 hours, the agency said.