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Water rules and religious freedom

Mast v. Fillmore County

Updated Oct 19, 2026

In brief

The Supreme Court wiped out the lower-court decision (vacated) and sent the case back to Minnesota (remanded); it did not decide which side should win.

Where it stands
Case remanded

Remanded · July 2, 2021

What it’s about
Amos Mast and other Amish residents challenged Fillmore County’s water-treatment rules under RLUIPA, saying the rules burdened their religious practices.
Who it affects
The Supreme Court wiped out the lower-court decision (vacated), but did not decide whether the county's requirements met federal religious-land-use protections.

Summary: written with AI from the case record.

Illustration for Mast v. Fillmore County
Conceptual illustration · AI-generated

What it's about

The Supreme Court wiped out the Minnesota Court of Appeals’ ruling (vacated it) and sent the case back to that court (remanded it) to reconsider in light of *Fulton v. Philadelphia*; it did not decide the RLUIPA questions.

The case concerns how the federal Religious Land Use and Institutionalized Persons Act (RLUIPA) applies when local governments enforce land-use and septic-system rules affecting religious practice.

Question presented

1. Does credible evidence regarding the Petitioners’ water use habits, topography and soil conditions surrounding plaintiffs’ residences, and the bacterial and viral composition of gray water, coupled with plaintiffs’ admission that the government has a compelling interest in protecting human health and the environment, satisfy RLUIPA’s requirement that the government demonstrate a compelling interest as applied to Petitioners? 2. Does a government satisfy RLUIPA’s “least restrictive means” test if it, in addition to providing scientific support for its own regulation, provides credible evidence demonstrating why a water-treatment system permitted in a minority of states is not suitable for use within its own state?

What the Court decided

Holding

Motion to proceed in forma pauperis and petition for a writ of certiorari granted. Judgment vacated and case remanded for further consideration in light of Fulton v. Philadelphia, 593 U. S. ___ (2021). Justice Alito, concurring in the judgment. Justice Gorsuch, concurring in the decision to grant, vacate, and remand.

Result
Remanded

What's next

The case returns to Minnesota for further consideration in light of Fulton v. Philadelphia. The Supreme Court sent it back (remanded), so the lower court will revisit the unresolved questions.

Why it matters

Whether the county showed a strong enough health and environmental interest and used the least burdensome approach remains open.

Documents

2

Docket activity

7
  • Case data updated: summary, question_presented, generation_metadata

    Oct 19, 2026 · Court records

  • New analysis added

    Sep 19, 2026 · Court records

  • AI analysis generated: Case Briefing

    Sep 19, 2026 · Generated

  • AI analysis generated: Decision Record

    Sep 19, 2026 · Generated

  • Case data updated: status, opinion_date

    Jul 25, 2026 · Court records

Show 2 more
  • Opinion added: Opinion

    Jul 2, 2021 · Court records

  • Brief added: Petition

    Jan 20, 2021 · Court records

More questions

4
What did the Amish families challenge in Mast v. Fillmore County?
They challenged Fillmore County's land-use and septic-system requirements, saying those rules conflicted with their religious beliefs.
What did the Supreme Court do in Mast v. Fillmore County?
It wiped out the lower-court decision (vacated) and sent the case back to Minnesota (remanded) for reconsideration in light of Fulton v. Philadelphia. It did not decide the legal questions.
Did the Supreme Court decide whether Fillmore County violated RLUIPA?
No. The order did not decide whether the county showed a strong enough health and environmental interest or used the least burdensome approach.
What happens next in Mast v. Fillmore County?
The case returns to Minnesota for further consideration in light of Fulton v. Philadelphia. The lower court will revisit the unresolved questions.

Sources

Primary materials plus reporting. Best-effort analysis: this explainer relies on a mix of primary materials and trusted secondary sources. Official filings and opinions remain authoritative.

Checked Sep 19, 2026Methodology

Court records and filings

Reporting and analysis