Beginning Monday, SAWS customers will have their water source switched.
SAWS said it will start pumping Edwards Aquifer water to areas now getting water from Lake Dunlap.
The switch is temporary to ensure water quality during the summer.
SAWS also said it is possible the taste and smell of the water could be different since a different chemical treatments is used, but the water is safe to drink.
Some hospitals and Dialysis centers could be affected and have been notified.
People with live fish might also want to test their water.