Clarification: An earlier version of this editorial mischaracterized the policies Maryland Gov. Larry Hogan (R) has taken on phosphorus regulation. Though Mr. Hogan did suspend the publication of phosphorus regulations upon taking office in January, his administration came to a compromise with the state legislature in March to pass and publish modified regulations. This version has been updated.

Satellite imagery of the Chesapeake Bay shows massive sediment, storm water runoff and sewer overflows. (NASA/GSFC, Rapid Response/NASA/GSFC, RAPID RESPONSE)

THE CHESAPEAKE Bay is the largest estuary in the United States. It is also one of the dirtiest. Though scientists have warned of the need to clean up the bay for years, very little headway has been made, and a recent Environmental Protection Agency assessment shows that states are not meeting agreed-upon pollution abatement targets. Leaders throughout the watershed should step up their cleanup efforts, and the EPA should hold accountable those who do not.

In 1983, the six states in the Chesapeake’s watershed and the District first partnered with the federal government and pledged to save the bay. However, after three more agreements — the latest and strongest in 2014 — states still have not made the progress they have promised on reducing nitrogen, phosphorus and sediment levels in bay waters. States are supposed to be 60 percent of the way toward the EPA’s suggested levels by 2017 and complete the final stretch by 2025. Maryland, Virginia and Pennsylvania make up most of the bay’s watershed. No state is on track to hit all three targets, but while Maryland and Virginia lag only a little behind, Pennsylvania’s improvement appears almost nonexistent.

Virginia Gov. Terry McAuliffe (D) has been a champion of conservation. Maryland Gov. Larry Hogan (R), on the other hand, campaigned against environmental regulations and suspended the publication of important restrictions on phosphorus output, formulated under predecessor Martin O’Malley, before reaching a compromise with the state legislature in March to pass and publish modified regulations. Pennsylvania Gov. Tom Wolf (D) is still unproven, succeeding an administration that largely ignored environmental issues.

Leaders cannot afford to ignore the catastrophe in the Chesapeake. The EPA also should not let them. Because the 2014 agreement imposes reporting requirements, the agency finally has the capability to track states’ behavior and punish them with fines or restrictions if they miss the mark. When states fail to act, they jeopardize the health of not just blue terns and osprey but also their own residents. Pollution in the rivers and streams that feed into the estuary contaminates well water in the bay’s watershed. Cleaner waters also mean more tourism. That, along with other benefits from a healthier ecosystem, could save states more than $22 billion dollars per year, according to the Chesapeake Bay Foundation.

Most state officials involved with the cleanup effort make a similar excuse for slow progress: They’re just getting started. But the struggle is 32 years old. Saving the bay should not be a partisan issue or the job of one governor or legislature. It should be a priority for anyone who has sworn an oath to serve the public interest, and one that spans administrations.