The city has now closed four beaches — one in Brooklyn and three on Staten Island — after a wastewater treatment facility dumped hundreds of millions of gallons of raw sewage into the Hudson River following a four-alarm fire last week.

The Department of Environmental Protection said water testing by the Department of Health has shown higher levels of bacteria at Sea Gate in Brooklyn.

Samples at Midland, Cedar Grove and South Beach on Staten Island did not show higher bacteria levels, but according to the DEP, they're also being closed as a precaution until the Health Department deems them safe for swimming.

The Health Department also said parts of the Hudson, East and Harlem rivers still aren't fit for swimming, canoeing, kayaking or any other recreational activities that could include direct contact with the water. Fishers are also advised not to eat what they catch at this time.

The North River Wastewater Treatment Plan processes some 120 million gallons of wastewater each day, according to the DEP.

Officials said they began dumping sewage into the Hudson River late Wednesday afternoon, and said they stopped doing so on Friday night.

But due to a mechanical error, the DEP has acknowledged that between 15 and 20 million gallons of sewage were released on Saturday, until the issue was resolved that afternoon.

The department said no new dumping has occurred since 3:30 p.m. on Saturday, and that it is working on backup pumping systems.