A long-running religious freedom case has come full circle, with a court ruling this week that a deeply conservative Amish community in Minnesota cannot be threatened with the loss of homes if its members don’t install septic systems to dispose of their bath, laundry and dish water.

The state Court of Appeals on Monday found that members of the Swartzentruber Amish community in southeastern Minnesota don't need to install septic systems to dispose of “gray water,” which is dirty water left from dishwashing, laundry, bathing, and other tasks not involving toilet waste. Two years ago, the U.S. Supreme Court reversed court rulings that had required the group to install septic tanks.

The Supreme Court ruling said governments can infringe on sincerely held religious beliefs only as a last resort and sent the case back to Minnesota, where the appellate panel ruled that state and local officials “failed to demonstrate a compelling state interest” to justify overriding the Amish families' religious freedom.

Here's a look at the legal dispute and the traditionalist religious community at the root of it.

The Amish are a Christian religious group that, based on its religious beliefs, shuns many modern technologies like electric and gas-powered machinery. Members are likely most recognizable by their use of horse-and-buggy transportation. There are more than 360,000 Amish in the U.S., and at least 32 states had an Amish population as of 2022, concentrated in the Midwest and East Coast states.

The Swartzentruber Amish are among the most restrictive concerning the use of technologies and eschew everything from tractors and refrigeration to phones and flushing toilets.

It's essentially about plumbing — specifically, the disposal of gray water. The Swartzentruber Amish do not have modern running water in their homes. Water arrives through a single line and is either pumped by hand or delivered by gravity from an external cistern.

In 2013, Fillmore County adopted an ordinance requiring most homes to have a septic system for the disposal of gray water. The Amish community sought an exemption “in the name of our Lord,” explaining that their religion forbids the use of such technology. They also offered an alternative used in more than a dozen other states that would allow them to funnel gray water from their homes by pipes to earthen basins filled with wood chips to filter solids and grease from the water as it drains, similar to how a septic system would work.

But the Minnesota Pollution Control Agency refused, and filed an administrative enforcement action against 23 Amish families in Fillmore County, threatening criminal penalties, civil fines and even to force them from their homes if they didn't comply. State officials presented testimony from an expert in court that said the mulch basins would not be as effective and that the mulch would quickly clog with solids and grease, requiring frequent relocating of new mulch pits.

State courts acknowledged that the requirement for septic tanks systems burdened the Amish community's religious beliefs. But the courts also found that septic systems — not mulch basins — would be the least-restrictive means for the Amish families to meet the government's interest in protecting public health and the environment.

The case made it all the way to the U.S. Supreme Court in 2021, which found that Minnesota courts overstepped. It said the burden was on the government to prove that the mulch basins wouldn’t work, not on the Amish to show they would. And it sent the case back to the Minnesota courts for reconsideration. Justice Neil Gorsuch wrote that if “the government can achieve its interests in a manner that does not burden religion, it must do so.”

Gray water is more hazardous to public health than it might sound, wastewater treatment expert Sara Heger testified in the lawsuit over the Fillmore County septic system requirement.

Heger, a researcher at the University of Minnesota, acknowledged that gray water is less dangerous than toilet waste, or “black water." But gray water carries contaminants such as human fecal material, harmful bacteria and viruses, and a variety of chemicals, commercial soaps and detergents that contain nitrogen and phosphorous that pose environmental problems.

“Whatever might make you sick, that’s also present in the gray water," she said.

The lower courts also found that while mulch basins may work in other states, the topography of Fillmore County — including fissures, fractures and sinkholes in the area's limestone bedrock — lends to more rapid travel of wastewater to ground and surface water than in other places.

If dumping gray water is occasional — like washing a car or wastewater by hunters and anglers — it poses very little risk, experts said. But large families produce much more wastewater where they live, testified Brandon Montgomery, with the Minnesota Pollution Control Agency.

An attorney for the families, Brian Lipford, argued that it made little sense for the state to target his clients over gray water disposal when it allows their use of outhouses — where residents essentially relieve themselves in a hole dug into the ground.

But state officials argued there are already regulations in place governing outhouses that require them to be a certain distance from wells and other sources of water. It's the addition of water in wastewater, they argued, that has the potential to spread contaminants much further.

Fillmore County Attorney Brett Corson is hoping to decide in the coming days whether to appeal to the Minnesota Supreme Court. He has 30 days from Monday's ruling to decide.

“We’re just taking the chance to digest the decision and consider what we’re going to do," he said.

Officials with the Minnesota Pollution Control Agency did not immediately respond to a request for comment on whether they’ll appeal.

Corson said he recognizes the issue is important to both the county and to the Amish.

“In a county like ours, the Amish community is a big part of our community,” he said. "They’re our neighbors and friends. We work together. It’s one of those things we have to make a solid decision on.”