The Nassau County Department of Health issued an advisory Saturday against swimming at 19 beaches in the county due to elevated levels of bacteria.

The advisory is a precautionary measure for beaches that are typically impacted by stormwater runoff following heavy rains, the county says. Parts of Nassau saw downpours Friday night as strong storms swept through the area.

"Stormwater runoff can impact bathing water quality by elevating bacteria levels, which may cause exceedances of the New York state standard for bathing water quality," the Health Department said in a statement.

For up-to-date recordings on closings and openings, residents can call 516-227-9700.

14 affected North Shore Beaches within Nassau County:

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