On a recent frigid morning in Flint, Michigan, as another winter storm barreled through town, residents were filing through a water resource center to stock up on bottled water.

“Here we are in a winter advisory, not supposed to be driving on the roads, and you’ve got to drive out to get water,” said Kortney Porteous as she picked up a case of water.

This is the new state of normalcy in the city of 100,000, which has been grappling with a lead-contamination crisis that has left many residents living on bottled water, unsure of the long-term health effects of high levels of lead in their water, and deeply mistrustful of government.

Residents are expecting another surge of attention to their plight as the Democratic presidential candidates come to Flint Sunday for a debate. And despite a feeling that they are a source of political gain, many residents are ready to capitalize on the attention to demand action.

“You know how it goes, it’s an election year,” said James McCovery, a Flint native. “If it wasn’t an election year, and they were already [elected], I feel like neither one of them would be working as hard as they are.” But he said he’s grateful that they are.

Hillary Clinton with Flint mayor Karen Weaver at the House of Prayer Missionary Baptist church in Flint on 7 February. Photograph: Rena Laverty/EPA

Hillary Clinton and Bernie Sanders have made Flint’s water crisis a hallmark of their campaigns: Sanders visited the city last week for a town hall and has called for Michigan governor Rick Snyder to resign. Clinton used her victory speech on Super Tuesday to highlight the situation, taking aim at Snyder by saying the “city’s children were poisoned by toxic water because the governor wanted to save a little money.” (Without naming Clinton, Snyder later responded, “Flint families need our help, not political rhetoric.”)

But when both candidates visit the city this week, residents are expecting more.

“I think they need to address the water situation and fix the pipes,” said Porteous, 30. “The main thing should be fixing our pipes … so we don’t have to continue to do this every day.”

Rick Carter, a Flint resident and executive director of Michigan Faith in Action, helped organize an event with local activists on Saturday ahead of the debate to bring attention to the plight of the city’s residents and present a list of demands.

“What would be your strategy to address the long-term health issues that will affect our children, not only in terms of healthcare, but what about some of the issues that they will face in terms of the performance gaps in the schools?” said Carter, 67, when asked what he wants the candidates to express on Sunday.

The Flint debate comes at a critical juncture, he said, “because we clearly need the spotlight to continue the national attention on this issue”. Residents in recent weeks have focused on proposals to replace the city’s network of lead service lines and their costly bills for municipal water service – some of the highest in the country. The Michigan legislature has appropriated $30m to Flint’s water utility; the money is expected to be used as a partial credit for service dating back to April 2014, covering about 65% of a resident’s bill. But residents say that doesn’t go far enough.

“Why are we continuing to pay for water that we still can’t drink?” Carter said.

Flint’s water became contaminated after the city, in April 2014, started pulling water from the Flint river. The decision, made as Flint was run by a state-appointed emergency manager, was crafted as an interim measure until a new water system Flint planned to join was operational. Following the switch, however, the Michigan department of environmental quality (DEQ) did not require Flint to treat the river water with anti-corrosion agents, allowing lead to leach off pipes and flow into households.

Many have pinned blame for the crisis on Snyder, who has released more than 38,000 emails from his executive staff and state departments involved in regulating Flint’s water. The emails have shown that his administration’s delay in coming to terms with the enormity of Flint’s water crisis was fuelled, in part, by a dismissive attitude among many aides. The governor has received approval by the state legislature for $70m in funds to aid the city’s residents, along with an additional $5m from federal government, but many residents say the response has been wholly inadequate. What’s more, they said, Snyder should be held accountable for overseeing an administration that, for months, rejected resident complaints and third-party research that earlier revealed the extent of the crisis.

“Something should happen,” said Jim Donovan, 53, outside a water resource site on the city’s south side. “I think [Snyder] knew. The emergency manager answers to one person: that’s the governor.”

Maya Britton lifts up a bottle of water in the pew alongside her mother Walida Britton, both of Flint. Photograph: Jake May/AP

Donovan said the situation hadn’t affected him as significantly as it had low-income residents of Flint, where more than 40% of the predominantly black population lives below the poverty line. But Donovan said he and his wife had been drinking bottled water since the April 2014 switch to the Flint River. The tap water, he said, “smelled terrible”.

“I have the means,” he said. “I just feel so bad for many people who don’t. One hundred dollars for a water bill to get tainted water to me is just criminal.”

Clinton and Sanders seemed to be “posturing” for residents to gain political points, Donovan said. But the debate helped bring additional attention to the issue, he added, “and that’s the biggest thing”.

“We need that,” he said. “So talking about that is still better. It’s still a good thing.”

Several miles away, on the city’s north side, a family of four walked toward another resource site to pick up a case of water. The father, Tom, who declined to give his last name, carried a tall walking stick, as his wife and children trailed alongside, pulling a sled on the unplowed city streets.

Tom said his household had decent water filters installed, but his family “didn’t know anything” about the water situation for a year after the switch to the Flint River – a fact that grinds him down to this day.

The publicity of the debate was helpful for Flint, he said, but politicians would “always be taking advantage of whatever they can, to do what they can”. His view of Clinton and Sanders reflects a sentiment now shared by many Flint residents of their state government.

“I couldn’t believe anything they said, really,” he said. “There’s just no confidence in politicians.”