Nassau County has banned swimming at 19 beaches for the second time this week due to elevated bacteria levels.

The Nassau County Department of Health says the ban is in effect as a precautionary measure.  The department states that storm water runoff from heavy rain can raise bacteria levels, potentially impacting the health of swimmers.

Health officials say the ban could be lifted Tuesday, July 31 at 7 a.m. barring additional heavy rainfall or further evidence of high bacteria levels.

The ban is in place for the following beaches:

Centre Island Sound – Bayville

Creek Club – Lattingtown

Lattingtown Beach – Lattingtown

Laurel Hollow Beach – Laurel Hollow

Morgan Sound – Glen Cove

North Hempstead Beach Park – Port Washington

Piping Rock Beach Club – Locust Valley

Pryibil Beach – Glen Cove

Ransom Beach – Bayville

Theodore Roosevelt Beach – Oyster Bay

Sea Cliff Village Beach – Sea Cliff

Soundside Beach – Bayville

Stehli Beach – Bayville

Tappen Beach – Glenwood Landing

Biltmore Beach Club – Massapequa

Hewlett Point Beach – East Rockaway

Island Park Beach – Island Park

Merrick Estates Civic Association – Merrick

Philip Healey Beach – Massapequa