Prompted by the Flint water crisis, Michigan is set to enact the country’s strictest rules on lead in water.

The new rules would require water utility companies to replace all lead pipes that connect water mains to buildings within the next 20 years, which could cost an estimated $2 billion. In addition, reports U.S. News & World Report, “the ‘action level’ for lead [found in water samples from high risk homes or buildings] would drop from 15 parts per billion, the federal limit, to 12 ppb in 2025.”

The rules were drafted by Michigan’s Department of Environmental Quality (DEQ), an office in the administration of Governor Rick Snyder. In its Request for Rulemaking, which is required to create new rules, the department wrote, “In wake of the Flint water crisis, there has been immense public pressure to update the rules to protect public health. Health providers, elected officials and the public at large have become aware that the existing rules and drinking water standards for lead are not health-based standards and not as protective of public health as they should be, especially for vulnerable populations of infants and children.”

The Flint water crisis was caused by an April 2014 decision to switch Flint’s water source from the Great Lakes Water Authority to the Flint River. The switch led to a rise in lead levels for residents of the majority Black city and 12 fatal cases of Legionnaires’ disease. There was also a decrease in fertility and an increase in infant deaths as a result of the lead. City dwellers still rely on filtered and bottled water for many common household tasks.

The proposed rules have been met with criticism from utility companies and municipal governments. “The state is giving the impression that the new rules are more protective of public health, but we don’t necessarily think so,” Kelly Karll, an engineer with the Southeast Michigan Council of Governments, told Governing.com:

Besides, she says, the new rules don’t even directly address the problem that caused the Flint water crisis. There, the city’s water became contaminated in 2014 after it switched from using water from Detroit’s Lake Huron to the Flint River, in an effort to cut costs. When the city made the switch, though, it did not add chemicals to prevent lead pipes from corroding, which is standard practice in the industry. So the river water stripped the protective coating that had built up over years on lead pipes in the city, which, in turn, lead to high lead levels in many homes.

But Michigan’s new plan doesn’t require cities to conduct a corrosion control study when it switches water sources, Karll notes.

Opponents to the new rules also claim the cost could be crippling to local governments. While the state estimates the cost of replacing pipes could be half a billion dollars, municipalities and water utility companies in Michigan place it closer to $2 billion. They would be responsible for this cost, not the state.

Michigan’s Joint Committee on Administrative Rules, comprised of 10 lawmakers, is currently considering the rule change.