New Jersey American Water is urging some of its customers to avoid non-essential water use until further notice.

The alert applies to customers in Hunterdon, Mercer, Middlesex and Somerset counties.

The reason is because of reduced water levels caused by a system issue at the Raritan-Millstone Water Treatment Plant.

The company says that if customers notice their water is discolored, they should let the cold water fun from the tap for 1-2 minutes until the water is clear.