A precautionary boil water notice is now in effect for parts of Guam following impacts from Typhoon Sinlaku. The Guam Waterworks Authority says the advisory comes after a sustained loss of pressure in portions of the island’s water distribution system, raising the risk of possible, though unconfirmed, bacterial contamination.

Officials say customers who did not experience any loss of water service are not affected. However, those who lost water for 48 hours or less are strongly advised to boil their water before use.

For those who experienced outages lasting 48 hours or more, boiling water is mandatory. Residents are advised not to drink tap water without boiling it first and to bring water to a rolling boil for at least three minutes before cooling and using it.

Boiled water should be used for drinking, brushing teeth, making ice, washing dishes, and preparing food. GWA says contamination can occur when pressure drops, runoff enters the system, or treatment processes are disrupted.

Crews are now collecting water samples across the island, with results expected within 24 to 48 hours. The agency says it will notify the public once testing confirms the water is safe and the boil water notice can be lifted.