Fillmore residents are under orders to boil any water from the tap through the weekend. A crew installing fiber optic cables led to the detection of a leak in the water system.
The construction site is near the corner of Ventura Street and Central Avenue in Fillmore.
Water quality tests will be done daily until the boil order can be lifted, which could be as soon as Sunday.
Until then, Fillmore residents are urged to use bottled water or boil water for at least a minute before drinking or cooking with it.