GREENSBURG — The first of two tests needed to lift a drinking water alert affecting 120,000 Western Pennsylvania residents has come back OK. If results of a second test today are fine, the boil water advisory issued Friday by the Municipal Authority of Westmoreland County will be lifted.

Residents in communities along the Kiski River in Westmoreland County have been advised to boil their water because a faulty filter might have allowed water tainted with dangerous algae to contaminate its entire supply. Officials say water should be boiled for a minute and then cooled.