For months, lead leached into the Flint, Michigan, water supply – and no one did anything about it. In the wake of that crisis, the nation is re-examining its water supply. But some families in central Massachusetts are wondering why the increased scrutiny hasn’t helped them.

Those families have been living on bottled water for months because their water supply is contaminated. State environmental officials say the only possible source they’ve identified is the biggest active municipal landfill in the state, just west of Worcester. But the operator of that landfill, Casella Waste Systems, Inc, says its safe.

“The landfill is such low-hanging fruit, it’s so easy to pick on,” says director of landfill development Tom Cue. “The fact is, neutral hydrologists, geologists have looked and tested and they keep telling us, ‘it does not look like it’s coming from you at all.’”

And, Cue says, the landfill fuels the local community; Casella gives the town of Southbridge nearly $2.5 million a year for hosting what looks like a big muddy hill.

“Right now the oldest section of the landfill is capped,” says landfill general manager John Farese. “Unless you looked at it on a map, you wouldn’t be able to tell an older section from a new section.”

But there’s a difference underneath. Unlike new parts of the landfill, the oldest sections don’t have the protective lining on the bottom that federal standards demand today. So, to make sure the landfill isn’t leaching into groundwater or nearby wetlands, Casella – which runs the landfill -- has monitoring stations along its periphery.

“What we’re looking at here is a groundwater monitoring well,” says Farese, standing next to a short nondescript pole on the outskirts of the landfill property. “So what happens is the locked top will be taken off, and a small jar is lowered down. And that’s how they sample the water down deep.”

Over the past few years chemicals have shown up in those samples, including something called 1,4-dioxane. It’s a solvent used in paint, adhesives, pesticides and stuff like household cleaners. Nearby resident Kevin Weldon had never heard of it, even though it was showing up in Casella’s tests of his well water. The company’s required to offer testing to homes with wells within a half mile of the landfill.

“We’d get a report once every three years with some contaminants that were found in our well. And nothing was ever said in the report as to this being unusual,” Weldon says. “So we thought whatever we had was something normal in the wells.”

Now he knows that, according to the EPA, 1,4 dioxane is a likely human carcinogen. In November, Casella told residents the chemical had exceeded government-recommended safety levels in Weldon’s well, and the wells of several neighbors in the town of Charlton, which borders the landfill. The Massachusetts Department of Environmental Protection made Casella truck in bottled water. Weldon’s neighbor, Melissa Whiting, was at the Charlton Board of Health meeting where company reps displayed a map of affected homes.

“And they said ‘the ones that are in green have some level of contamination,’” she recalls.  “’The ones that are in red have a very high level of contamination. And those folks have been notified and we’ve given them bottled water.’ So I looked at my husband and I said, ‘counting over on the map, I’m pretty sure that’s our house.’ And we didn’t know that. So after the meeting was over we went and looked and sure enough, there’s our house in flashing red.”

Six months later, Casella is still providing bottled water for 28 families, nine of which have contamination that exceeds safety limits. Wil Gallien is one of them. His well tests three times the recommended limit for 1,4 dioxane, and it frightens him.

“Taking a shower – they tell you it’s safe. I’m not a chemist. I don’t know that showering in this is good. But just the thought that you’re showering in 1,4 dioxane at any level is disturbing,” he says. “A lot of us have children. Pets. My pets drink bottled water.”

At Charlton Board of Health meetings, residents plead for what they see as the only permanent solution – municipal water. Get Casella to pipe it in, they say.

“It’s getting ridiculous,” resident John Jordan told board of health members at a recent meeting. “Everybody knew about this all this time, and nobody seems to be pushing to get any action done.”

Town health agent Jim Philbrook tells them to talk to the Department of Environmental Protection.

“I don’t take what you say lightly, any of you. We’re not desensitized to how you guys are living,” he says. “You’re right it is frustrating, to the point where I give out the DEP’s phone number like its – ‘call Mark Baldi, here’s his phone number, call him.’”

Mark Baldi is Deputy Regional Director for the Bureau of Waste Site Cleanup in MassDEP’s Central Regional Office. He says the state’s identified only one possible source of the contamination: the landfill. He agrees that Casella should pay to put in water lines and remediate the area.

“There is information there that indicates they could likely be the source of the contamination of the private wells,” he says. And, in response to whether that information is enough to hold Casella responsible, Baldi says, “It is, yes.”

But, he says, the regulatory process could take a while.

“Under the regulations they have up to six years actually to submit a permanent or temporary solution,” Baldi says. Asked whether families with contaminated wells could be on bottled water for that long, he says,”We hope not but we do have other sites where that does happen.”

Baldi says the state will make Casella supply families with bottled water for as long as thier well water contamination continues – even if the levels fall below recommended limits. But Casella maintains there’s no proof the landfill is responsible for the contamination. Director of landfill development Tom Cue says their geologists haven’t found a way chemicals could be traveling underground toward the affected homes.

“What the problem is that we’re trying to prove a negative. We’re trying to prove it’s not us,” he says. “Finding another source has been difficult, but we’re still looking.”

Cue says culprits could include laundry detergent, spills by small businesses, or some other chemical spill that happened decades ago and is just now migrating underground toward the effected wells.

“It is easy to point a finger at us, we are a landfill – nothing sexy about it, we take trash, that’s what we do,” he says. “Until there’s a better option, we are a necessary evil, for lack of a better term.”

State environmental officials say despite the unresolved contamination issues, the Southbridge landfill may soon be getting bigger – because Casella has applied to expand.