Rialto Fire Department responded to reports of a water main break. Arriving crews located a large amount of water flooding at least two, possibly three city blocks that was flowing from a broken main line in front of a residence in the 2300 block of W Loma Vista Dr. The water flowing from the main line caused the roadway to crack. Water department personnel marked the cracked pavement with cones to avoid motorists driving over it citing possible danger of a sink hole developing. Residents of the affected areas also reported very low water pressure inside their homes. Water department personnel are currently working to stop the flow of water and initiate repairs. It's unknown at this time when repairs will be completed and when the water pressure in the homes affected will be restored to normal.