Newburgh must switch its water source again -- and it could cost hundreds of thousands of dollars.

Earlier this month, officials discovered the city's original water source is contaminated with PFOS. The city switched to Brown's Pond, but low water levels are forcing the city to switch again to the Catskill Aqueduct.

On Tuesday, the city started using water from both the aqueduct and pond. And on Monday, the city will completely switch over to the Catskill Aqueduct.

That could cost the city roughly $230,000 per month.

Previously, Mayor Judy Kennedy said the state agreed to pay for any costs associated with this move.

Meanwhile, Congressman Sean Patrick Maloney says a possible source of Newburgh's water issues has become a priority as part of a larger investigation through the Department of Defense.

He's released a statement saying the DOD will look into the Stewart Air National Guard Base in Newburgh. The DOD had already been looking into the issue of groundwater contamination linked to firefighting foam.

Maloney says that was at a number of different areas, but did not originally include Stewart. Now, Maloney's office says it's "at the top of the list."

Stewart Air National Guard Base hosts the Guard's 105th Airlift Wing.