Four Nassau County beaches have been closed to bathing, a "precautionary measure" to guard against any negative impact from higher bacterial levels brought on by Thursday's heavy rainfall, county health officials said.

Closed are Creek Club, Locust Valley; Laurel Hollow Beach; North Hempstead Beach Park, Port Washington; and Piping Rock Beach Club, Lattingtown.

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Storm water runoff can increase bacterial levels and impact water quality, officials said.

The health department provides recorded information on beach openings and closings at 516-227-9700.