The Water Department has imposed townwide restrictions on outdoor water use. The department said the restrictions were mandated under its state water-management permit, which calls for limits when the measured stream flow on the Taunton River near Bridgewater drops below 130.5 cubic feet per second for three consecutive days. The restrictions are needed to protect aquatic life and ensure a sustainable drinking water supply for communities in the Taunton River basin. The rules ban nonessential outdoor water use, but allow sprinklers to be used one day a week before 9 a.m. and after 5 p.m., and watering by a hand-held hose any day from 7 to 9 a.m. and 5 to 7 p.m. The restrictions will be maintained until the stream flow remains above the threshold for seven consecutive days.