The water is expected to be discolored because of turbulence created by water changing direction from easterly to westerly and the increased volume, Walzl said.
The water flow has been easterly for 11 to 12 years, he said.
"There is not a known health threat associated with using the water; however, customers may want to draw sufficient quantities prior to the scheduled time of the flow reversal for their use," Walzl said.
City officials urge customers to check water for discoloration before operating washing machines.
The water's color is expected to improve tonight and Wednesday, Walzl said.
The switch in the water flow will save on pumping costs because the water will be flowing downhill instead of uphill, he said.
The Breichner plant provides an additional and backup water source to the city's R.C. Willson Water Treatment Plant near Williamsport. The plant feeds the Edgemont Reservoir.
Walzl said the Breichner plant will run at maximum capacity.
At the plant's dedication in December, Walzl said it could produce 4.8 million gallons of treated water a day at peak capacity, but would average about 3 million gallons a day.
The plant south of Smithsburg off Crystal Falls Drive can produce only about half of the 10 million gallons of water the city's roughly 75,000 water customers use daily, Walzl has said.
Customers who continue to have discolored water or other problems may call the Hagerstown Water Department at 301-739-8577, ext. 169.