Every summer, swimmers wade into water of the Chesapeake Bay region. Anglers cast lines, and watermen harvest crabs and oysters. And every year, scientists and regulators ask, “Is the water clean enough?”
The answer depends on how you define “clean,” and that definition is complex. Behind every headline about algae blooms, dead zones or pollution limits is a framework of legal thresholds, scientific measures and government responsibilities that most people never see.
Jackie Goodrum, an attorney with the Chesapeake Legal Alliance, talked with the Chesapeake Bay Journal to explain the basics.
Question: What are water quality standards, exactly?
Answer: Water quality standards are legal thresholds set by states and approved by the federal government. They define what a body of water must achieve to support its intended uses, such as swimming, fishing, providing drinking water or sustaining aquatic life. When Congress passed the Clean Water Act in 1972, they made it unique in terms of timing and purpose, pushing for more progress and more stringent permit limits until all of the standards are achieved. Congress also set an enforceable goal in the 1980s to make all U.S. waters swimmable and fishable — which might surprise many people in the Bay region.
Water quality standards have three components: designated uses (what the water is supposed to be good for), numeric or narrative criteria (the measurable conditions required to protect those uses) and policies that prevent backsliding.
For the Bay, water quality is based on three main criteria: dissolved oxygen (the amount available for fish and other aquatic life), water clarity (measured largely through the health of underwater grasses) and chlorophyll-a (which indicates algae growth fueled by nutrient pollution).
The Bay watershed has 92 tidal management sections that cover the Bay and some of its rivers. Each one has its own criteria based on local conditions. That’s because healthy water in a shallow Potomac tributary looks different from healthy water in the Bay’s deep mainstem.
In 2010, the U.S. Environmental Protection Agency took an unusually direct step to improve Bay water quality by establishing its total maximum daily load or “pollution diet.” It defines the amount of pollutants that the water can receive and still meet all applicable standards. The Bay TMDL is the largest ever developed. It set caps on nitrogen, phosphorus and sediment coming from the entire 64,000-square-mile watershed across seven jurisdictions. Still, only 29.4% of the Bay and its tidal rivers met water quality standards during the most recent assessment period in 2021–2023.
Q: Who sets and enforces these standards?
A: The Clean Water Act establishes the national framework. But primary responsibility for writing the standards into law belongs to states and tribes, which adopt their own standards that the EPA must review and approve. The Bay’s situation is unique, because the states adopted criteria for dissolved oxygen, water clarity and chlorophyll-a that were developed and recommended by the EPA. Also, the standards are locally tailored and cover Bay tidal segments as well as some streams and rivers.
Enforcement is layered. The EPA oversees the big picture: reviewing impaired waters lists, evaluating progress and imposing consequences when progress falls short. But the pollution permitting process is where the oar meets the water. State environmental agencies issue and enforce discharge permits that must be consistent with TMDLs. In theory, and spurred by a 2025 U.S. Supreme Court decision, state agencies could place numeric pollution limits directly into the permits.
Q: Which level of government has the most power to protect waters near me?
A: The federal Clean Water Act establishes a baseline that no state or locality can legally fall below. But states hold significant power: they write the criteria for what healthy water looks like in their jurisdiction and decide how to reduce pollution through permitting and enforcement. Local governments regulate land use and have a big role to play in controlling polluted stormwater runoff. The Clean Water Act recognizes the critical need to control runoff from nonpoint sources, like agriculture, but leaves policy development to the states and local governments.
Q: How do I know if my local waterway is failing?
A: Every state must publish a list of waterways that don’t meet standards. This is known as the “impaired waters” list. Each listing specifies the offending pollutant and its cleanup priority.
States and tribes submit these lists to the EPA in even-numbered years. If a state or tribe omits waters that should be included, the EPA can add them.
You can search for local waterways in your state environmental agency’s impaired waters database, the EPA’s TMDL search tool or the Chesapeake Bay Program’s watershed assessments. Note that while there are tens of thousands of chemicals known to science (and registered by the EPA), only a few pollutants are addressed in the impairment lists and TMDLs.
Q: Do the standards change? How often?
A: Yes, and the pace matters. The Clean Water Act requires states and tribes to review standards every three years, though reviews are often delayed and revisions infrequent. Any change requires public comment and EPA approval. States can strengthen standards or propose weaker ones.
For the Bay, the core criteria have been remarkably stable since their development in 2003. The 2010 TMDL limits remain in force. But the 70,000-plus TMDLs in place across the nation are rarely revised or, sadly, achieved. For the Bay, shifts occur more regularly with the two-year milestone commitments that each state submits, allowing incremental course corrections.
The central question for Bay water quality is what comes next. Cleanup leaders did not meet their voluntary 2025 deadline for the TMDL. But the standards haven’t expired, and the TMDL is still in effect. The question is whether the will exists to provide enforcement mechanisms or to reallocate the responsibilities among polluters in order to make them more enforceable. The next generation of policymakers will also have to account for a changing climate, too.
