Status of Efforts to Restore Chesapeake Bay Water Quality
link to page 2 
Updated June 30, 2023
Status of Efforts to Restore Chesapeake Bay Water Quality
For decades, Chesapeake Bay jurisdictions (Delaware,
Bay jurisdictions do not meet their commitments. Examples
Maryland, New York, Pennsylvania, Virginia, West
of potential backstop federal actions include expanding
Virginia, and the District of Columbia), multiple federal
CWA permit coverage to unregulated sources, conditioning
and local agencies, and others have worked to improve
or redirecting EPA grants, and requiring additional
water quality in the Bay. Nonetheless, poor water quality in
pollutant load reductions from point sources.
the Bay and its tidal tributaries persisted, prompting
litigation that ultimately required the U.S. Environmental
WIPs
Protection Agency (EPA) to establish a Total Maximum
Bay jurisdictions each created WIPs, which detailed
Daily Load (TMDL)—or a “pollution budget” for the Bay.
specific steps they planned to take to meet and maintain
Established in 2010, the TMDL includes interim and final
their pollutant allocations under the TMDL. Bay
goals for each jurisdiction to achieve by 2017 and 2025,
jurisdictions developed WIPs in three phases and submitted
respectively. As the target date for the final TMDL goals
them to EPA in 2010 (Phase I), 2012 (Phase II), and 2019
approaches, stakeholders are examining the progress toward
(Phase III). Phase I and II WIPs described specific actions
these goals and the continuing challenges Bay jurisdictions
and controls to be implemented by 2017 and 2025 to
and others face in improving the Bay’s water quality.
achieve applicable water quality standards. Phase II WIPs
built upon Phase I WIPs by including more specific local
What Is a TMDL?
actions. Phase III WIPs include refined actions and controls
The Clean Water Act (CWA) requires states to identify
the jurisdictions intend to take through 2025 to meet the
waters that are “impaired” by pollution (i.e., not meeting
goals of the TMDL (see “Phase III WIPs”).
state water quality standards). For those waters, the act
directs states to establish a TMDL, which is a calculation of
Milestones
the amount of a pollutant that can enter a waterbody and
Bay jurisdictions submitted their first set of milestones to
still allow the waterbody to meet state water quality
EPA in 2012. These milestones identify short-term goals on
standards for that pollutant. TMDLs include a quantitative
an interim two-year basis, which can be used to assess
assessment of the pollutant sources and reductions required
progress toward the longer-term goals. The most recent set
to attain water quality standards. TMDLs address both point
of milestones covers 2022-2023.
sources of pollution (e.g., wastewater or industrial
discharges) and nonpoint sources (e.g., urban runoff and
2017 Midpoint Assessment
agricultural runoff). The CWA directs states to submit
The Chesapeake Bay TMDL called for a midpoint
TMDLs to EPA for approval. If EPA disapproves, the act
assessment in 2017 to review jurisdictions’ progress toward
directs EPA to develop a TMDL for the waterbody.
meeting the goals established in the TMDL. According to
data submitted by Bay jurisdictions and assessed by EPA,
Chesapeake Bay TMDL
jurisdictions collectively surpassed the 2017 interim goals
EPA established a Chesapeake Bay TMDL in 2010
for reducing phosphorus and sediment, but they did not
pursuant to consent decrees resolving litigation over
achieve the 2017 interim goal for reducing nitrogen.
impairment of Bay waters in Virginia and the District of
Reductions of specific pollutants in individual Bay
Columbia. The TMDL was also a key feature of a 2010
jurisdictions varied widely.
strategy to restore the Chesapeake Bay. The Federal
Leadership Committee for the Chesapeake Bay, chaired by
EPA also assessed the Bay jurisdictions’ implementation of
EPA, created the strategy in response to Executive Order
programs to achieve pollution reductions across sectors and
13508, issued in May 2009.
found that achievements and shortfalls varied. The
wastewater sector in particular had much success, achieving
The Chesapeake Bay TMDL is the largest single TMDL
its 2025 load reduction goals 10 years ahead of schedule
developed to date in terms of area covered. It addresses all
through treatment plant upgrades, technology advances, and
segments of the Bay and its tidal tributaries that are
nutrient discharge limitations in CWA discharge permits.
impaired from discharges of nitrogen, phosphorus, and
Efforts to reduce nitrogen deposition from atmospheric
sediment. The TMDL set two broad goals: an interim goal
sources (e.g., power plants and vehicles) were also on track
of having 60% of pollution control measures needed to
to meet the 2025 TMDL goals. However, while
attain water quality standards in place by 2017 and a final
jurisdictions had improved their urban/suburban stormwater
goal of having 100% of the measures in place by 2025.
regulatory programs, EPA reported that overall loads in the
EPA is using an accountability framework to implement the
sector continued to increase due to population growth and
TMDL. This framework includes four elements: watershed
development. EPA also found that, in some cases,
implementation plans (WIPs), two-year milestones, EPA
jurisdictions were not making sufficient progress in
tracking and assessment, and backstop federal actions if
implementing their planned policies and programs in the
https://crsreports.congress.gov
Status of Efforts to Restore Chesapeake Bay Water Quality
agricultural sector and were falling short of meeting the
Progress Toward 2025 Goals
pollution reduction goals in that sector.
Although the Bay jurisdictions have made progress in
implementing practices and controls to achieve TMDL
As part of the 2017 assessment, EPA identified Delaware’s
goals, EPA indicates that the jurisdictions are “off course”
agricultural sector, Maryland’s urban/suburban stormwater
in meeting their goals. Bay jurisdictions have reported that,
sector, New York’s wastewater sector, and Pennsylvania’s
as of 2021, they have BMPs in place to achieve 49% of the
trading/offsets sectors as needing enhanced oversight. This
nitrogen reductions, 64% of the phosphorus reductions, and
means EPA identified specific concerns with the
100% of the sediment reductions needed to attain applicable
jurisdictions’ implementation of strategies to meet TMDL
water quality standards when compared to the 2009
goals. The agency may take additional actions to ensure that
baseline established in the Bay TMDL. In FY2024, EPA
the jurisdiction stays on track.
plans to evaluate progress toward meeting the 2022-2023
milestone commitments.
In addition, EPA identified two sectors in Pennsylvania—
agriculture and urban/suburban stormwater—as requiring
Challenges
backstop action levels, meaning the agency had substantial
EPA and other stakeholders acknowledge that, despite
concerns with actions taken to meet the TMDL goals. For
progress in reducing pollutants to the Bay, challenges in
these two sectors, EPA has taken actions intended to get the
achieving the TMDL goals and improving the Bay’s water
jurisdiction on track, such as establishing an expectation for
quality remain. While jurisdictions’ efforts have prevented
more frequent and detailed reporting and an expectation
a significant increase in pollution, they face challenges in
that Chesapeake Bay funds provided to Pennsylvania would
meeting targets due to factors such as land use changes,
be applied to specific priority watersheds.
population growth, changes in climate, and the voluntary
nature of BMPs implemented to address nonpoint source
Phase III WIPs
pollution. EPA’s Chesapeake Bay Program (CBP) estimates
In 2019, EPA received final Phase III WIPs from Bay
that 27% of the Bay area met water quality standards in
jurisdictions specifying actions they plan to implement
1985, improving to the mid-30% range by 2020.
between 2019 and 2025 to achieve the TMDL goals. Bay
jurisdictions incorporated midpoint assessment results and
In May 2023, the CBP’s Scientific and Technical Advisory
new science and data, such as improved modeling tools,
Committee (STAC), an independent entity that provides
higher-resolution land cover data, additional monitoring
scientific and technical advice to CBP, found that (1) efforts
data, and greater variety of approved best management
to reduce nonpoint sources of nutrients have not resulted in
practices (BMPs) in their Phase III WIPs. Bay jurisdictions
sufficient levels of BMP implementation to meet the
also considered other factors, such as population growth,
TMDL, and (2) the implementation that has occurred has
land use changes, and climate change. In 2018, a committee
not been as effective at producing the pollutant reductions
composed of EPA and other Bay partners revised nitrogen
as expected, meaning more controls would be needed to
and phosphorus targets to reflect refinements to the most
achieve the target pollutant reductions. In addition, while
recent version of the Chesapeake Bay watershed model.
nutrient and sediment reductions have led to some water
Some of the revised targets require additional pollution
quality improvements in some portions of the Bay, no
reductions beyond the original 2025 goals, whereas other
significant improvement has been measured in the majority
targets require lesser reductions. The new targets reflect
of the water quality standards established for the various
that pollution controls in some areas may be more effective
Bay habitats (especially in deep waters), suggesting a
than similar controls in other areas.
lagging response. STAC concluded that ongoing changes
may require thinking differently about what constitutes a
EPA’s evaluations of the Bay jurisdictions’ Phase III WIPs
“restored” Chesapeake Bay. It also suggested potential
indicated that both New York’s and Pennsylvania’s plans
opportunities for improvements. For example, prioritizing
were deficient in certain areas. While New York submitted
management actions in areas or habitats where pollution
an amended plan, which EPA found would meet the state’s
reduction limits might be achieved first and yield more
portion of the 2025 goal, EPA found that Pennsylvania’s
immediate impacts on living resources may magnify the
amended plan did not meet the state’s portion of the 2025
impacts of TMDL implementation.
goal. Other Bay jurisdictions and the Chesapeake Bay
Foundation sued EPA in 2020 for failing to enforce
Congressional Interest
provisions of the CWA by not requiring Pennsylvania to
Congress has funded Bay restoration efforts through EPA
develop a plan to fully meet pollution reduction goals. (The
and other agencies for decades. In FY2023, Congress
lawsuit initially included claims regarding New York’s plan
appropriated $92.0 million to EPA for the CBP. In addition,
and EPA’s review of that plan, but those claims were
Congress provided $238.0 million in supplemental
dismissed after EPA approved New York’s amended plan.)
appropriations through the Infrastructure Investment and
In April 2023, EPA reached a tentative settlement with the
Jobs Act (P.L. 117-58) to be provided in equal amounts in
plaintiffs in which EPA proposed to increase compliance
each of FY2022 through FY2026. The President’s FY2024
and enforcement efforts, prioritize its efforts in certain
budget requests $92.1 million for CBP. Congress may
Pennsylvania jurisdictions that contribute the most pollution
consider additional oversight of the CBP and its efforts to
or have the largest impacts, and determine whether certain
restore the Bay as the 2025 TMDL goal approaches.
stormwater dischargers or animal feeding operations should
be designated as significant contributors of pollutants that
Laura Gatz, Specialist in Environmental Policy
are therefore subject to permitting requirements.
IF11402
https://crsreports.congress.gov
Status of Efforts to Restore Chesapeake Bay Water Quality
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11402 · VERSION 3 · UPDATED
Updated June 30, 2023
Status of Efforts to Restore Chesapeake Bay Water Quality
For decades, Chesapeake Bay jurisdictions (Delaware,
Bay jurisdictions do not meet their commitments. Examples
Maryland, New York, Pennsylvania, Virginia, West
of potential backstop federal actions include expanding
Virginia, and the District of Columbia), multiple federal
CWA permit coverage to unregulated sources, conditioning
and local agencies, and others have worked to improve
or redirecting EPA grants, and requiring additional
water quality in the Bay. Nonetheless, poor water quality in
pollutant load reductions from point sources.
the Bay and its tidal tributaries persisted, prompting
litigation that ultimately required the U.S. Environmental
WIPs
Protection Agency (EPA) to establish a Total Maximum
Bay jurisdictions each created WIPs, which detailed
Daily Load (TMDL)—or a “pollution budget” for the Bay.
specific steps they planned to take to meet and maintain
Established in 2010, the TMDL includes interim and final
their pollutant allocations under the TMDL. Bay
goals for each jurisdiction to achieve by 2017 and 2025,
jurisdictions developed WIPs in three phases and submitted
respectively. As the target date for the final TMDL goals
them to EPA in 2010 (Phase I), 2012 (Phase II), and 2019
approaches, stakeholders are examining the progress toward
(Phase III). Phase I and II WIPs described specific actions
these goals and the continuing challenges Bay jurisdictions
and controls to be implemented by 2017 and 2025 to
and others face in improving the Bay’s water quality.
achieve applicable water quality standards. Phase II WIPs
built upon Phase I WIPs by including more specific local
What Is a TMDL?
actions. Phase III WIPs include refined actions and controls
The Clean Water Act (CWA) requires states to identify
the jurisdictions intend to take through 2025 to meet the
waters that are “impaired” by pollution (i.e., not meeting
goals of the TMDL (see “Phase III WIPs”).
state water quality standards). For those waters, the act
directs states to establish a TMDL, which is a calculation of
Milestones
the amount of a pollutant that can enter a waterbody and
Bay jurisdictions submitted their first set of milestones to
still allow the waterbody to meet state water quality
EPA in 2012. These milestones identify short-term goals on
standards for that pollutant. TMDLs include a quantitative
an interim two-year basis, which can be used to assess
assessment of the pollutant sources and reductions required
progress toward the longer-term goals. The most recent set
to attain water quality standards. TMDLs address both point
of milestones covers 2022-2023.
sources of pollution (e.g., wastewater or industrial
discharges) and nonpoint sources (e.g., urban runoff and
2017 Midpoint Assessment
agricultural runoff). The CWA directs states to submit
The Chesapeake Bay TMDL called for a midpoint
TMDLs to EPA for approval. If EPA disapproves, the act
assessment in 2017 to review jurisdictions’ progress toward
directs EPA to develop a TMDL for the waterbody.
meeting the goals established in the TMDL. According to
data submitted by Bay jurisdictions and assessed by EPA,
Chesapeake Bay TMDL
jurisdictions collectively surpassed the 2017 interim goals
EPA established a Chesapeake Bay TMDL in 2010
for reducing phosphorus and sediment, but they did not
pursuant to consent decrees resolving litigation over
achieve the 2017 interim goal for reducing nitrogen.
impairment of Bay waters in Virginia and the District of
Reductions of specific pollutants in individual Bay
Columbia. The TMDL was also a key feature of a 2010
jurisdictions varied widely.
strategy to restore the Chesapeake Bay. The Federal
Leadership Committee for the Chesapeake Bay, chaired by
EPA also assessed the Bay jurisdictions’ implementation of
EPA, created the strategy in response to Executive Order
programs to achieve pollution reductions across sectors and
13508, issued in May 2009.
found that achievements and shortfalls varied. The
wastewater sector in particular had much success, achieving
The Chesapeake Bay TMDL is the largest single TMDL
its 2025 load reduction goals 10 years ahead of schedule
developed to date in terms of area covered. It addresses all
through treatment plant upgrades, technology advances, and
segments of the Bay and its tidal tributaries that are
nutrient discharge limitations in CWA discharge permits.
impaired from discharges of nitrogen, phosphorus, and
Efforts to reduce nitrogen deposition from atmospheric
sediment. The TMDL set two broad goals: an interim goal
sources (e.g., power plants and vehicles) were also on track
of having 60% of pollution control measures needed to
to meet the 2025 TMDL goals. However, while
attain water quality standards in place by 2017 and a final
jurisdictions had improved their urban/suburban stormwater
goal of having 100% of the measures in place by 2025.
regulatory programs, EPA reported that overall loads in the
EPA is using an accountability framework to implement the
sector continued to increase due to population growth and
TMDL. This framework includes four elements: watershed
development. EPA also found that, in some cases,
implementation plans (WIPs), two-year milestones, EPA
jurisdictions were not making sufficient progress in
tracking and assessment, and backstop federal actions if
implementing their planned policies and programs in the
https://crsreports.congress.gov
Status of Efforts to Restore Chesapeake Bay Water Quality
agricultural sector and were falling short of meeting the
Progress Toward 2025 Goals
pollution reduction goals in that sector.
Although the Bay jurisdictions have made progress in
implementing practices and controls to achieve TMDL
As part of the 2017 assessment, EPA identified Delaware’s
goals, EPA indicates that the jurisdictions are “off course”
agricultural sector, Maryland’s urban/suburban stormwater
in meeting their goals. Bay jurisdictions have reported that,
sector, New York’s wastewater sector, and Pennsylvania’s
as of 2021, they have BMPs in place to achieve 49% of the
trading/offsets sectors as needing enhanced oversight. This
nitrogen reductions, 64% of the phosphorus reductions, and
means EPA identified specific concerns with the
100% of the sediment reductions needed to attain applicable
jurisdictions’ implementation of strategies to meet TMDL
water quality standards when compared to the 2009
goals. The agency may take additional actions to ensure that
baseline established in the Bay TMDL. In FY2024, EPA
the jurisdiction stays on track.
plans to evaluate progress toward meeting the 2022-2023
milestone commitments.
In addition, EPA identified two sectors in Pennsylvania—
agriculture and urban/suburban stormwater—as requiring
Challenges
backstop action levels, meaning the agency had substantial
EPA and other stakeholders acknowledge that, despite
concerns with actions taken to meet the TMDL goals. For
progress in reducing pollutants to the Bay, challenges in
these two sectors, EPA has taken actions intended to get the
achieving the TMDL goals and improving the Bay’s water
jurisdiction on track, such as establishing an expectation for
quality remain. While jurisdictions’ efforts have prevented
more frequent and detailed reporting and an expectation
a significant increase in pollution, they face challenges in
that Chesapeake Bay funds provided to Pennsylvania would
meeting targets due to factors such as land use changes,
be applied to specific priority watersheds.
population growth, changes in climate, and the voluntary
nature of BMPs implemented to address nonpoint source
Phase III WIPs
pollution. EPA’s Chesapeake Bay Program (CBP) estimates
In 2019, EPA received final Phase III WIPs from Bay
that 27% of the Bay area met water quality standards in
jurisdictions specifying actions they plan to implement
1985, improving to the mid-30% range by 2020.
between 2019 and 2025 to achieve the TMDL goals. Bay
jurisdictions incorporated midpoint assessment results and
In May 2023, the CBP’s Scientific and Technical Advisory
new science and data, such as improved modeling tools,
Committee (STAC), an independent entity that provides
higher-resolution land cover data, additional monitoring
scientific and technical advice to CBP, found that (1) efforts
data, and greater variety of approved best management
to reduce nonpoint sources of nutrients have not resulted in
practices (BMPs) in their Phase III WIPs. Bay jurisdictions
sufficient levels of BMP implementation to meet the
also considered other factors, such as population growth,
TMDL, and (2) the implementation that has occurred has
land use changes, and climate change. In 2018, a committee
not been as effective at producing the pollutant reductions
composed of EPA and other Bay partners revised nitrogen
as expected, meaning more controls would be needed to
and phosphorus targets to reflect refinements to the most
achieve the target pollutant reductions. In addition, while
recent version of the Chesapeake Bay watershed model.
nutrient and sediment reductions have led to some water
Some of the revised targets require additional pollution
quality improvements in some portions of the Bay, no
reductions beyond the original 2025 goals, whereas other
significant improvement has been measured in the majority
targets require lesser reductions. The new targets reflect
of the water quality standards established for the various
that pollution controls in some areas may be more effective
Bay habitats (especially in deep waters), suggesting a
than similar controls in other areas.
lagging response. STAC concluded that ongoing changes
may require thinking differently about what constitutes a
EPA’s evaluations of the Bay jurisdictions’ Phase III WIPs
“restored” Chesapeake Bay. It also suggested potential
indicated that both New York’s and Pennsylvania’s plans
opportunities for improvements. For example, prioritizing
were deficient in certain areas. While New York submitted
management actions in areas or habitats where pollution
an amended plan, which EPA found would meet the state’s
reduction limits might be achieved first and yield more
portion of the 2025 goal, EPA found that Pennsylvania’s
immediate impacts on living resources may magnify the
amended plan did not meet the state’s portion of the 2025
impacts of TMDL implementation.
goal. Other Bay jurisdictions and the Chesapeake Bay
Foundation sued EPA in 2020 for failing to enforce
Congressional Interest
provisions of the CWA by not requiring Pennsylvania to
Congress has funded Bay restoration efforts through EPA
develop a plan to fully meet pollution reduction goals. (The
and other agencies for decades. In FY2023, Congress
lawsuit initially included claims regarding New York’s plan
appropriated $92.0 million to EPA for the CBP. In addition,
and EPA’s review of that plan, but those claims were
Congress provided $238.0 million in supplemental
dismissed after EPA approved New York’s amended plan.)
appropriations through the Infrastructure Investment and
In April 2023, EPA reached a tentative settlement with the
Jobs Act (P.L. 117-58) to be provided in equal amounts in
plaintiffs in which EPA proposed to increase compliance
each of FY2022 through FY2026. The President’s FY2024
and enforcement efforts, prioritize its efforts in certain
budget requests $92.1 million for CBP. Congress may
Pennsylvania jurisdictions that contribute the most pollution
consider additional oversight of the CBP and its efforts to
or have the largest impacts, and determine whether certain
restore the Bay as the 2025 TMDL goal approaches.
stormwater dischargers or animal feeding operations should
be designated as significant contributors of pollutants that
Laura Gatz, Specialist in Environmental Policy
are therefore subject to permitting requirements.
IF11402
https://crsreports.congress.gov
Status of Efforts to Restore Chesapeake Bay Water Quality
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11402 · VERSION 3 · UPDATED