Police believe someone left a fire hydrant open, draining the water supply.
The city is still asking residents to conserve water until the towers fill back up.
The water shortage led to the closing of schools and local businesses.
Acting Mayor Tommy Scott told CBS 11, “Someone is sabotaging some of this stuff and tampering with it so right now we looking into getting that taken care of.”
Ferris ISD said schools will be back open Tuesday.
A boil water notice remains in effect for the area.
Both the Ferris Police and Fire Departments are handing out bottled water until the water shortage ends.