The swimming area at Round Valley Recreation Area has been closed due to a water quality issue from stormwater run-off.
The recreation area is at Round Valley Reservoir, New Jersey's deepest lake, in Hunterdon County.
The swimming area closed Tuesday, when its water failed a test for fecal coliform, and it remained closed Wednesday because it did not pass a test done Tuesday.
Lawrence Hajna of the New Jersey Department of Environmental Protection said results from today's water testing will be available tomorrow.
He explained all recreational bathing areas routinely are tested for fecal coliform and those areas are closed if levels are too high.