A city police officer is being treated for Legionnaires' disease after harmful bacteria are found at an East Harlem stationhouse.

Police department officials said preliminary test results found traces of Legionella bacteria in water samples at the 23rd Precinct on 102nd St. sometime between Friday and Saturday night.

The bacteria cause Legionnaire's disease, and are generally found in cooling towers and water systems.

Police said a tower in the building has been shut off since last October, and a new one installed last month is not yet active.

The precinct's hot water supply has also been turned off as a precaution.

City health department officials said officers can continue working in the building as they test the building's plumbing.

In 2015, a series of Legionnaires outbreaks in the Bronx killed a dozen people and sickened more than 100 others.

Health department officials said the bacteria is not contagious and is treatable with antibiotics.

Between 200 and 400 cases of the disease are reported in the city each year.