LANSING, Mich. (AP) — A judge on Friday let stand Michigan’s toughest-in the-nation drinking water regulations that were created after the Flint crisis, dismissing a lawsuit that was brought by major Detroit-area water systems over concerns such as the cost of having to replace hundreds of thousands of underground lead pipes.

State Court of Claims Judge Christopher Murray said the rules, which former Gov. Rick Snyder’s administration finalized more than a year ago, are procedurally, substantively and constitutionally valid. He said the plaintiffs failed to make a convincing argument that the new regulations are not rationally related to assuring the long-term health of the state’s public water supplies.

The suit was filed in December by the Great Lakes Water Authority, whose system is used by about 40% of Michigan’s residents; Oakland County Water Resources Commissioner Jim Nash; and the cities of Detroit and Livonia.

They argued, among other things, that the state mandated the replacement of service lines without a meaningful study of affordability and funding, and failed to consider the legality of giving away a public service “for free” on private property.

The Great Lakes Water Authority said the opinion is not a final order in the case, because Murray earlier this week granted the plaintiffs’ motion to amend their complaint.

Michigan created the country’s strictest regulations for lead in tap water in the wake of the man-made emergency in Flint, where the toxic metal leached into the supply in 2014 and 2015 due to a lack of corrosion-control treatment following a switch in the water source while the city was under state emergency management.

Underground lead service lines connecting water mains to houses and other buildings will be replaced by 2040, unless a utility can show regulators it will take longer under a broader plan to repair and replace its water infrastructure.

The “action level” for lead will drop from 15 parts per billion, the federal limit, to 12 in 2025.