Swimming at Zach’s Bay was closed on Friday as a precautionary step after heavy rain fell, state parks department officials said.

The beach, part of the Jones Beach State Park, also was shut earlier this week, but that was after water quality tests revealed a health risk caused by a slightly elevated bacteria count.

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The culprit likely was Monday’s rains; storms can overwhelm sewer systems, releasing contaminants.

The statement issued Friday by the Office of Parks, Recreation and Historic Preservation said that the latest temporary closure “is a precautionary step to assure protection of the health and safety of our swimmers.”

The beach likely will remain shut at least on Saturday.

The parks department said it would review additional water quality tests to determine when to reopen the beach.