This is an excerpt from Circle of Blue's August 17, 2020 episode of What's Up With Water. Over two decades ago, New York City and its rural partners launched a groundbreaking, multibillion-dollar watershed protection plan, and the review is in – a panel of experts says the effort sufficiently protects the city’s drinking water supply from contamination. The Catskill and Delaware watersheds are the source of most of the city’s drinking water. Since 1997, New York City has spent some $2.5 billion on ecosystem protection in those watersheds. The money has been put to good use: upgrading 42 wastewater treatment plants, buying out land to prevent development, and stabilizing stream channels to prevent erosion. The funds also replaced failing septic tanks, trapped pollutants in stormwater, and helped dairy farmers control nutrients and pathogens in manure.