A section of Altoona is currently under a boil water notice following a water main break that occurred early yesterday. The Altoona Water Authority has issued an alert for residents in the Eldorado Springs and Klock developments, as well as some parts of southwest Altoona. The break, on the 800 block of 36th Street, may have caused contamination, or service interruptions in these areas. Affected customers were notified by phone by the authority. They are advised to boil their water vigorously for one to three minutes before consumption, including for drinking, cooking, and brushing teeth. The advisory is expected to remain in effect for 36 to 72 hours while the water supply is tested. The authority will issue a subsequent notification when the water is confirmed to be safe for normal use.