The Louisville Water Company has issued a boil water advisory for more than 20-thousand customers in eastern Jefferson County.Officials say the advisory was prompted by a break in a 60 inch main near Highway 42 near Prospect.The advisory area is bounded by the Gene Snyder Freeway to the north, Hurstbourne Parkway to the west, Floyd's Fork to the east and Taylorsville Road to the south. It includes customers served by the English Station Reservoir.The water company says customers should, until further notice:Bring all water used for drinking, food preparation and cooking to a rolling boil for three minutes before consuming..Avoid using chilled water lines on refrigerators.Avoid using ice from automatic ice machinesMore information is available at the water company's website.