The Potomac River scored below the Chesapeake Bay's overall health grade in a new report card released Tuesday, Oct. 13.

The bay itself earned a C+, its highest mark in nearly 40 years of monitoring, the University of Maryland Center for Environmental Science (UMCES) said. The 56% score represents a six-point jump from the year before, when erratic weather and persistent heat dragged the grade to a C, as The Banner first reported.

UMCES presented the findings at a George Mason University research center on the Potomac River, south of Washington, D.C. No specific letter grade for the Potomac region has been published, but the river scored worse than the bay overall.

Long-term trends for dissolved oxygen, underwater grasses and nitrogen and phosphorus pollution are all improving across most of the bay's 15 regions. Eight showed improving health trends, UMCES said. Virginia's Lower Bay earned a B+, the best score on record for any single region. The Lower Western Shore received the lowest mark, a D-.

Not everything is trending up. Water clarity and algae growth are moving in the wrong direction.

Alexandra Fries, the UMCES program manager who led the assessment, said persistent drought in Maryland likely helped the score by reducing polluted runoff. But the six-point swing was too large to pin on dry weather alone, she said.

Theaux Le Gardeur, a fishing guide and Gunpowder Riverkeeper, offered a counterpoint. He told The Banner he has observed fewer fish species returning to his river to spawn and worries about rising salt concentrations.

"I've got an 11-year-old in Baltimore County Public Schools, and if he came home with a C, I'd be raising my eyebrows," Le Gardeur said.

The report card arrives alongside several other positive markers. Gov. Wes Moore's administration announced in August that Maryland had met 100% of its sediment and phosphorus reduction goals and 99% of its nitrogen reduction goal under the 2014 Chesapeake Bay Watershed Agreement, according to a governor's office press release.

Underwater grass coverage in Maryland's portion of the bay expanded nearly 13% in a single year, growing from 36,799 acres in 2024 to 41,419 acres in 2025, Maryland DNR reported in September. Mattawoman Creek, a Potomac River tributary, maintained 85% of its 792-acre restoration goal. Oyster populations in Maryland waters more than tripled between 2005 and 2023, according to a DNR management review released Oct. 2.

Federal support remains uncertain. President Trump rescinded an Obama-era executive order in September that had organized the federal Chesapeake Bay cleanup response since 2009. Funding for the Chesapeake Bay Program has not been cut, but Maryland officials are still assessing the impact, Maryland Matters reported. The EPA separately announced Oct. 5 that it will distribute $90 million for bay cleanup projects, including $53 million in matching grants for 83 projects across the watershed, 32 of them in Maryland, according to Maryland Matters.

The next UMCES report card, covering 2026 data, is expected in fall 2027.