At his home near Kearsley Park, on the east side of Flint, Michigan, Tony Palladeno Jr. grabs his keys and a pair of 1-liter medical-grade plastic bottles—one full and one empty. He filled the first yesterday, with slightly cloudy water from his own tap. To fill the second, he strolls a few doors down to a two-story home he once rented out. The place looks move-in-ready, with new windows, fresh trim, and crisp beige siding. But it's vacant, just like three other rentals Palladeno owns on this block.

Some of his tenants moved out in the winter of 2015, after much of the city's municipal water turned murky, reeking like swamp muck. Others stuck it out a little longer, even when the city issued boil advisories (E. coli in the water) and a notice about high levels of trihalomethanes, a carcinogenic byproduct of disinfectants.

That autumn, 21 percent of the tap water sampled from the dilapidated, bohemian neighborhood around Kearsley Park was positive for lead contamination. In fact, every residential zip code in Flint has houses that have tested hot.

In January, Genesee County health officials reported another waterborne threat—87 cases of Legionnaires' disease in two years, with 10 deaths. It's one of the largest outbreaks in US history. The entire city was vulnerable to either heavy metal or bacterial poisoning.

Palladeno's bottles are part of a sampling effort run by the Michigan Department of Environmental Quality to map the chaos. Entering his rental, Palladeno ignores the chirp from a dying smoke alarm and heads to the kitchen sink to fill his bottle. "Bada bing," he says, although it comes off flatly. Palladeno is supposed to drop his sample at city hall, but he has a more pressing concern. He's not thirsty now, but he will be. So he steers his late-model Buick downtown, following signs tacked to wooden pallets leaning against trees and street posts. The messages—WATER PICKUP, with big blue arrows—lead to a fire station parking lot, where National Guardsmen in fatigues and orange vests watch over 6-foot-tall towers of bottled water.

You used to have to show ID—one case per person. After an uproar, that changed to two, no license required. Sometimes Palladeno and his wife come together and take four, stockpiling. Today one of the Guardsmen recognizes Palladeno and starts loading his trunk. "I tell you what I'm afraid of," Palladeno says. "Once summer hits and the heat comes, we're going to be fighting for this water

At city hall, he joins a procession of dazed-looking people dropping off water samples. It doesn't feel like science in action. In fact, it's a mess: Somehow many volunteers got the wrong kind of bottle, so their samples get set off to the side. Others have lost paperwork, so they've guessed at a few methodological particulars.

Palladeno was already skeptical. Like most Flint residents, he has come to distrust people from any level of government. He figures if anyone is going to save Flint, it'll be people like him, who grew up there.