The Chesapeake Bay (Bay) is the largest estuary in the United States. Congress has described it as a "national treasure" (P.L. 106-457), and the United States has designated wetlands within the Bay as "Wetlands of International Importance." The Bay is part of the broader Chesapeake Bay watershed, an over 64,000-square-mile area that extends across parts of Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia (Figure 1). The watershed is home to more than 18 million people and thousands of species of plants and animals.

Figure 1. Boundaries and Rivers of the Chesapeake Bay Watershed

Source: CRS adapted from National Geographic Education, "Chesapeake Bay Map Gallery."

Over time, the Bay's ecological conditions have deteriorated due to land-use changes, increased sediment loads and nutrient pollution, the use and spread of chemical contaminants and fertilizer, overfishing and overharvesting of aquatic species, and the introduction of invasive species. These changes have resulted in reductions to economically important fisheries, such as oysters and crabs; the loss of habitat, such as underwater vegetation and sea grass; annual dead zones, as nutrient-driven algal blooms die and decompose; and potential impacts to tourism, recreation, and real estate values.

Governors of Chesapeake Bay watershed states, the U.S. Environmental Protection Agency (EPA), and other partners have developed multiple agreements to address aspects of these conditions in the Bay. EPA and nonfederal entities signed a revised Chesapeake Bay Watershed Agreement in December 2025—the most recent commitment to restore and conserve the estuary and watershed. Congress has examined, and may continue to examine, Bay restoration efforts, including through oversight and legislation.

Past Restoration Efforts

Joint state and federal Bay restoration attempts began in the early 1980s, when the governors of Maryland, Pennsylvania, and Virginia; the D.C. mayor; the chair of the state-level Chesapeake Bay Commission; and the EPA Administrator signed the Chesapeake Bay Agreement of 1983 (1983 agreement). Under the 1983 agreement, the signatories agreed to "improve and protect the water quality and living resources of the Chesapeake Bay estuarine systems." In 1987, Congress codified the Chesapeake Bay Program (CBP) through amendments to the Clean Water Act (CWA) and directed EPA to "improve the water quality of the Bay," among other functions (33 U.S.C. §1267). Congress has since amended the statute and directed the EPA Administrator to develop and implement restoration management plans with partners and offer financial and technical restoration assistance.

Since 1983, the original signatories and governors from Delaware, New York, and West Virginia have partnered on new agreements and revisions, including in 1987, 2000, and 2014. The 2014 agreement contained 10 goals and 31 outcomes to be implemented by 2025. Some of the outcomes established under EPA's 2010 Chesapeake Bay Total Maximum Daily Load (TMDL) were incorporated into the 2014 agreement's water quality goal.

Most Recent Agreement

In December 2025, federal and state partners signed the most recent Chesapeake Bay Watershed Agreement (2025 agreement). The signatories released a draft agreement in July 2025. Many commenters, including some Members of Congress, scientists, environmental groups, the public, and others argued that the proposed plan needed to be strengthened. The final agreement addresses some of the concerns regarding timelines and state pollution reductions raised by commenters.

The 2025 agreement identifies four "interconnected" goals—"thriving habitat, fisheries, and wildlife," "healthy landscapes," "clean water," and "engaged communities"—and 21 corresponding outcomes. CBP is responsible for updating or developing management strategies to achieve the outcomes, as well as monitoring, assessing, and reporting progress and coordinating action among partners. The strategies are to be re-evaluated every six years, with goals and outcomes realized by 2040 or earlier.

Congressional Considerations

Progress Toward Restoration

Congress continues to be interested in whether and how quickly progress is being made in restoring the Bay. Several entities, including CBP and nongovernmental organizations, periodically evaluate the Bay and its watershed, with differing priorities, methods, and results. For example, both CBP and the University of Maryland Center for Environmental Science (UMCES) annually assess the Bay's ecological, societal, and economic conditions. According to a CBP 2024-2025 annual report, progress under the 2014 agreement was made in some areas (e.g., oyster habitat and public access) but was lacking in others (e.g., forest buffer plantings and wetland conservation). UMCES rated the Bay and broader watershed as moderately healthy in 2024 (with grades of C and C+, respectively). The Bay and watershed health grades have remained relatively consistent over the reporting time frames. EPA also uses an accountability framework that includes evaluation of two-year milestones to measure progress in attaining the Bay TMDL's water quality goals. These evaluations are scheduled to continue under the 2025 agreement through 2040.

Entities evaluating progress recognize positive outcomes of Bay restoration efforts but acknowledge several factors that pose challenges to meeting Bay-related goals, including land use changes, population growth, changes in climate, and the voluntary nature of actions used to address nonpoint source (i.e., diffuse) pollution. Nonpoint source pollution (e.g., agricultural and other runoff) is generally unregulated.

Potential congressional actions could include directing federal agencies to focus on specific types of improvement within certain time frames or continuing to allow federal and nonfederal partners the discretion to do so (e.g., H.R. 3898). Congress may also consider incentivizing certain efforts. For instance, H.R. 2091 and S. 971 would incentivize and support efforts to reduce agricultural runoff. Some stakeholders have argued for an alternative mechanism: the creation of an interstate compact among Bay agreement signatories. Such a compact would need congressional approval and would make certain activities obligatory and transfer decisionmaking power to the Chesapeake Bay Commission, for example. Others may argue that additional legislation is not needed, and restoration efforts could be improved with better implementation of existing authorities.

Federal Government Role in Restoration

Congress may scrutinize whether the federal government's Bay restoration efforts are sufficiently coordinated and resourced. In contrast to restoration efforts in other large waterbodies, such as the Great Lakes, Congress has not directed federal agencies to establish an overarching action plan or provided a unified funding stream. Most other geographic programs authorized in the CWA require development of an overarching action or management plan or identify which existing plan the program will follow. Congress may consider whether authorizing a single plan and/or establishing a dedicated funding stream would benefit Bay restoration efforts or may choose to maintain the status quo on this issue.

Congress may also examine whether federal restoration efforts are effectively coordinated and integrated with state activities. Apart from requirements under the CWA, federal and state roles in Bay restoration are not defined by law. In the Bay, coordination between state and federal agencies is largely achieved through the voluntary 2025 agreement and CBP, where decisions are determined by consensus. Congress may consider whether to direct federal agencies and nonfederal partners to work together in certain ways. For example, H.R. 7788 and S. 3986 would authorize the CBP Office to serve as an advisory member of certain state watershed programs. Congress could also consider approving an interstate compact that would dictate specific roles, as described previously.

Funding and Total Cost of Restoration

Congress has appropriated funds in recent years and may consider if, and how much, to appropriate to various federal agency restoration activities in the future. The Chesapeake Bay Accountability and Recovery Act (CBARA; P.L. 113-273) requires the Office of Management and Budget (OMB) to compile Bay restoration funding information from seven federal departments in an annual crosscut report. According to OMB, federal agencies estimated $591.1 million in funding for Bay restoration activities in FY2024. The U.S. Department of Agriculture had the greatest share at $266.0 million. Using the crosscut reports, CRS estimates that Congress has provided over $5.7 billion in total funding levels for federal Bay restoration activities between FY2014 and FY2024.

Stakeholders have varied opinions on whether and how much federal funding should go toward Bay restoration. Some would like to reduce or eliminate federal funding for some Bay restoration activities. For example, the Trump Administration proposed to reduce or eliminate funding for the Chesapeake Bay Geographic Program in each of FY2018-FY2021, and FY2027. Others, such as the Chesapeake Bay Commission and environmental groups, have argued to maintain or increase funding for activities to potentially accelerate restoration progress. Modifications to the amount appropriated toward restoration efforts may dictate the types of activities funded and the speed at which restoration goals are met.

Determining the appropriate level of funding may depend on how restoration is defined and how much it is expected to cost in total. While groups have previously attempted to estimate the total potential cost of restoring and maintaining the Bay, those estimates have not been comprehensive and may now be outdated. For example, a 2014 report estimated it would take $5 billion per year to implement the TMDL by 2025, not considering other restoration needs. Congress may consider directing CBP or another entity to develop an up-to-date total cost estimate, including the types of restoration activities, expected results, timeline for achievement, and/or the anticipated federal share.