New target date set with revised Chesapeake Bay Watershed Agreement
New modeling estimates from the Chesapeake Bay Program show that the jurisdictions of the Bay watershed—New York, Pennsylvania, Maryland, Virginia, Washington, D.C., Delaware and West Virginia—continue to work toward their pollutant reduction goals. As of 2025, jurisdictions have met 100% of their goal for sediment reduction, 90% of their goal for phosphorus reduction and 57% of their goal for nitrogen reduction.
Most jurisdictions in their Phase III Watershed Implementation Plans committed to having practices in place to reduce the nitrogen, phosphorus and sediment in order to achieve the Bay’s water quality standards. Chesapeake Bay Program models estimate how much nitrogen, phosphorus, and sediment is reduced through those practices, comparing 2025 conditions to the 2009 baseline established under the Chesapeake Bay Total Maximum Daily Load (Bay TMDL). According to the latest model estimates:
● Overall sediment entering the Bay declined 6.8% from 18.8 billion pounds in 2009 to 17.6 billion pounds in 2025, achieving 100% of the sediment goal of 18.6 billion pounds.
● Overall phosphorus entering the Bay declined 21.4% from 16.8 million pounds in 2009 to 13.2 million pounds in 2025, achieving an estimated 90% of the phosphorus goal of 12.8 million pounds.
● Overall nitrogen entering the Bay declined 15% from 297.1 million pounds in 2009 to 252.7 million pounds in 2025, achieving an estimated 57% of the nitrogen goal of 219.5 million pounds.
Reducing the amount of nitrogen, phosphorus and sediment that enters the Bay improves water quality, wildlife habitat, and economic and recreational opportunities across the estuary. Excess nitrogen and phosphorus fuel algae blooms that can create low-oxygen “dead zones,” threatening fish, shellfish and other aquatic life. Meanwhile, excess sediment can smother oyster reefs and block the sunlight needed for healthy underwater habitats.
Since 2009, upgrades to wastewater treatment plants have accounted for the majority of nitrogen and phosphorus reductions across the watershed—contributing to 64% of all nitrogen reductions and 61% of phosphorus reductions. More recently, nonpoint sources such as agriculture and stormwater runoff have played a bigger role, accounting for the largest reductions in nitrogen and phosphorus between 2020 and 2025. For sediment, the agricultural sector was one of the largest sources of reduction, accounting for 43% of all reductions since 2009. Chesapeake Bay Program partners see reductions from these nonpoint sources as being critical to meeting future goals. The Executive Council set 2025 as the target date for these pollutant reduction goals to be met. Under the Chesapeake Bay Watershed Agreement updated in 2025, jurisdictions will now continue working toward these pollutant reduction targets through 2030.
The targets will be revised by 2030 based on the latest watershed modeling, monitoring data and research findings, and jurisdictions will then develop plans to meet these updated targets by 2040.
