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Florida v. Georgia, 592 U.S. 433 (2021)

Why this matters: Florida spent roughly 8 years and a reported $57 million arguing that Georgia’s water use destroyed its oyster industry, and lost 9 to 0. This is the modern bar for getting a court to divide an interstate river. It is very high, and that’s the point.

Doctrine: Interstate equitable apportionmentequitable apportionmentThe US Supreme Court dividing an interstate river between states that cannot agree. The evidence bar is very high. Florida spent over a decade and lost.

Case name and citation

Florida v. Georgia, 592 U.S. 433 (2021). No. 142, Original.

Court and year

Supreme Court of the United States, original jurisdiction. Decided April 1, 2021. Unanimous, 9 to 0. Opinion by Justice Barrett.

One-line holding

Florida failed to prove by clear and convincing evidence that Georgia’s water consumption caused serious injury to its oyster fisheries or river ecosystem, so its exceptions to the Special Master’s report were overruled and the case was dismissed.

Facts

The Apalachicola-Chattahoochee-Flint River Basin starts near Atlanta and runs south to Apalachicola Bay on the Gulf.

Georgia consumes basin water heavily: metro Atlanta municipal supply upstream, and agricultural irrigation in the Flint River basin further south.

Florida claimed the resulting low flows in the Apalachicola River caused serious harm, most visibly the collapse of its oyster fishery in Apalachicola Bay around 2012.

Florida filed an original action seeking equitable apportionmentequitable apportionmentThe US Supreme Court dividing an interstate river between states that cannot agree. The evidence bar is very high. Florida spent over a decade and lost., asking the Court to cap Georgia’s consumption.

The litigation was long and procedurally tangled. The first Special Master, Ralph Lancaster, recommended dismissal, concluding Florida could not show redressability because the Army Corps of Engineers controls reservoir operations and was not a party.

In Florida v. Georgia, 585 U.S. 401 (2018), the Court held that the Special Master had applied too strict a standard to the threshold redressability question, at least absent further findings. It remanded with instructions to make definitive findings on whether Florida had proved serious injury caused by Georgia, how much reducing Georgia’s consumption would increase Apalachicola flows, and how much that increase would redress Florida’s injuries.

Special Master Lancaster retired. Judge Paul Kelly was appointed. After supplemental briefing and argument he issued an 81-page report recommending the Court deny Florida relief for several independent reasons.

Did Florida carry its burden of proving that Georgia’s alleged overconsumption caused serious injury of the magnitude required for equitable apportionment?

Holding and reasoning

Unanimous. Florida loses, case dismissed.

The Court restated what a state must show to obtain equitable apportionment. First, a threatened or actual injury of “serious magnitude” caused by the other state’s water consumption. Second, that the benefits of a decreedecreeThe court order at the end of an adjudication, spelling out exactly who gets how much water and in what order. would substantially outweigh the harm it causes.

The burden is heavy, and deliberately so. A state seeking apportionment “bears a burden much greater than does a private party.” Both Florida and Georgia are riparianriparianThe eastern US rule, and Wisconsin's rule. If your land touches a lake or stream, you get reasonable use of that water, shared with everyone else whose land touches it. The rights come with the land and generally cannot be sold separately from it. states with “an equal right to make a reasonable usereasonable useYou can use the water however you like until it unreasonably harms someone else's use. This is Wisconsin's groundwater rule. The catch: it is enforced by a lawsuit after the harm, not by a permit beforehand.” of shared basin water, and Florida had to prove its case by clear and convincing evidence.

On the facts, the Court conducted its own independent review of the record and agreed with the Special Master.

The line that carried the opinion: “Considering the record as a whole, Florida has not shown that it is ‘highly probable’ that Georgia’s alleged overconsumption played more than a trivial role in the collapse of Florida’s oyster fisheries.”

The Court also acknowledged what it could not do. “Of course, the precise causes of the oyster collapse remain a subject of ongoing scientific debate. As judges, we lack the expertise to settle that debate.”

Other plausible causes were on the table, including Florida’s own fishery management decisions and increased harvesting after the Deepwater Horizon spill.

Florida’s exceptions were overruled and the case dismissed.

Why it matters

Read this alongside Kansas v. Colorado (1907), which created equitable apportionment, and the arc becomes clear. See 1907-kansas-v-colorado.md.

Kansas proved real harm in 1907 and lost because the balance was not destroyed. Florida proved harm in 2021 and lost because it could not prove causation to a clear and convincing standard.

The lesson for any state considering an equitable apportionment suit: don’t. Interstate water litigation is expensive, slow, and almost always unsuccessful. Florida’s effort ran from 2013 to 2021 and reportedly cost tens of millions of dollars for a unanimous loss.

The causation problem is structural, and it will recur. Complex ecological collapses have multiple causes. Courts require clear and convincing proof that one defendant’s water use was a substantial factor. Ecosystems don’t produce evidence that clean.

Which brings the story back to compactscompactA binding agreement between states that Congress approves. Once approved it becomes federal law and overrides conflicting state rules. The Great Lakes Compact is one.. The ACF basin has never had one, despite decades of negotiation attempts. States that negotiate a compactcompactA binding agreement between states that Congress approves. Once approved it becomes federal law and overrides conflicting state rules. The Great Lakes Compact is one. and get congressional consent avoid this. States that litigate get an 81-page report and a dismissal.

The Great Lakes states did it the other way. See ../03-wisconsin-great-lakes/.

What it means for a landowner today

No direct application to a Wisconsin parcel.

The indirect value is a reality check on how water conflicts actually get resolved.

  • Litigation between states is a poor remedy. If a shared water resource matters to your land, the protective mechanism worth caring about is the compact or the permit system, not the possibility of a lawsuit.
  • Causation is hard to prove in water cases at every scale. If a large well nearby lowers your lake, you will face a version of Florida’s problem: proving that this pumping, rather than drought, land use change, or something else, caused the harm. Wisconsin’s high capacity wellhigh capacity wellIn Wisconsin, a well (or all wells on 1 property combined) capable of pumping 100,000 gallons a day or more. These need DNR approval. An ordinary house well does not. framework matters partly because it addresses harm before it happens, rather than requiring proof afterward. See 2011-lake-beulah-v-dnr.md.
  • The best time to develop evidence is before the harm, not after. Baseline data on water levels and well performance is worth collecting.

Who to involve if you want that baseline: a hydrogeologisthydrogeologistA geologist who specializes in groundwater. Worth hiring for acreage, tricky geology, or any large planned withdrawal., and the DNR’s existing monitoring records for the water body.

Subsequent history / is it still good law

Good law as of July 2026 and the current authoritative statement of the equitable apportionment standard.

The case is over. Dismissal ended more than a decade of Supreme Court litigation between the 2 states, though disputes over the ACF basin continue through Army Corps reservoir operations and related federal litigation.

Apalachicola Bay’s oyster fishery was closed to wild harvest by Florida in 2020 for a multi-year restoration period. Confirm its current status before relying on any statement about the fishery.

The 2018 decision, 585 U.S. 401, remains relevant for its treatment of the redressability threshold.

Sources

Research demo, not legal advice. Facts current as of July 2026. Water law is state-specific and moves quickly, so confirm anything you plan to act on with a licensed attorney and the relevant state agency.