A Baltimore County judge has upheld Maryland’s permit governing stormwater pollution from more than a thousand industrial sites statewide, closing out — for now — a legal challenge environmental groups had pursued for nearly four years and prompting renewed calls for lawmakers to strengthen the state’s stormwater rules through legislation instead.
The Circuit Court for Baltimore County ruled this month that the Maryland Department of the Environment’s so-called 20-SW general industrial stormwater permit complies with state and federal law, rejecting arguments from a coalition of environmental groups that the permit fails to keep pace with heavier rainfall driven by climate change and allows toxic pollutants to reach Maryland waterways largely unmonitored. The case, filed in Baltimore County Circuit Court under case number C-03-CV-22-005075, was brought by the Chesapeake Bay Foundation along with the Chesapeake Legal Alliance, representing Blue Water Baltimore and Gunpowder Riverkeeper, and the Environmental Integrity Project, representing Potomac Riverkeeper Network.
The 20-SW permit, first issued by MDE in November 2022, sets the pollution-control requirements for industrial facilities across Maryland — including scrap yards, auto yards, coal-handling operations and landfills — that discharge stormwater runoff into state waterways. The Chesapeake Bay Foundation filed its initial petition for judicial review in December 2022, arguing the permit relied on outdated precipitation data and lacked measurable pollution limits tied to the Chesapeake Bay’s federal cleanup targets. MDE agreed to a limited remand covering three sections of the permit — provisions governing “no exposure” certifications, comprehensive site compliance evaluations and stormwater pollution prevention plans — and reopened those sections for public comment in 2023. When the agency issued an amended version of the permit, known as 20-SW-A, in February 2025, environmental groups said it still failed to address their core concerns, and the case proceeded to oral arguments in April 2026 before this month’s ruling.
Attorneys for the environmental groups said the decision leaves Marylanders exposed to ongoing risk. “This is a huge loss for clean water in Maryland,” said Matt Stegman, a Chesapeake Bay Foundation staff attorney. “Stormwater pollution is only getting worse from climate change and more development.” Fellow CBF attorney Sheronda Rose said the ruling “undermines the intent of state and federal environmental laws,” while Abel Russ of the Environmental Integrity Project pointed to a specific gap in the permit’s monitoring requirements: facilities face no required sampling for four of every five years in a given permit cycle. Gunpowder Riverkeeper Theaux Le Gardeur cited MDE’s own inspection record, noting the agency visited only 26 of 116 regulated industrial sites along the Bush, Gunpowder and Middle rivers over a five-year term.
The ruling extends a pattern in which Maryland courts have generally deferred to MDE’s discretion in setting stormwater permit terms, even when judges have acknowledged the underlying pollution concerns as legitimate. In a related 2024 case over separate municipal stormwater permits for Baltimore City and County, the Appellate Court of Maryland ruled that MDE has “wide flexibility” to choose permit terms it believes will achieve water quality standards, with the panel writing that the agency “had a rational basis” for its choices even while acknowledging “genuine factual disputes” about the permits’ real-world effects. MDE has typically declined to comment publicly when courts rule in its favor in these cases, a pattern that continued after this month’s decision.
The department has separately defended its stormwater permitting approach in other recent proceedings. When MDE renewed the state highway system’s separate stormwater permit last year, Maryland Environment Secretary Serena McIlwain said the update “strengthens our ability to protect the Chesapeake Bay and the businesses and communities that rely on it,” even as the same coalition of environmental groups argued that permit, too, fell short by leaving implementation largely to the state highway agency’s discretion.
With the litigation over the 20-SW permit largely resolved at the circuit court level, environmental groups say they’re shifting focus toward the policy process, where multiple opportunities for public input are expected over the next year. Those include upcoming renewals of Municipal Separate Storm Sewer System, or MS4, permits for Maryland’s largest jurisdictions, along with new stormwater-related legislation the groups plan to push during the Maryland General Assembly’s 2027 session. State data cited by the environmental coalition shows Maryland made no measurable progress reducing stormwater pollution between 2009 and 2023, a statistic advocates argue underscores the need for legislative, rather than purely regulatory, reform.
The groups have not said whether they intend to appeal this month’s ruling to a higher court.
