Over the weekend, the Park Fire grew to more than 360,000 acres, prompting evacuation orders and warnings around Chico, California. …months from now when the rains come and the fires are extinguished, a hidden threat could put communities at risk once again. …Around 60 to 65 percent of the United States’ drinking water comes from forested areas. As fires burn in these areas, they increase the risk of cancer-causing and toxic substances entering water supplies. An estimated 53.3 million U.S. residents who live in areas with significant wildfire risk may face damaged drinking water infrastructure from those flames. …Megafires burn land at higher temperatures across wider areas than standard wildfires, putting watersheds across the United States at greater risk. …As wildfires burn hotter and consume more trees and structures, water quality will continue to worsen, research suggests. …To meet these risks, it will take a coalition of informed community members, scientists and city officials to work toward solutions to protect clean water supplies. [Access to the full story requires a Washington Post subscription]