State Of The Sound: The 2026 Long Island Sound Report Card Released By Save The Sound

NEW HAVEN, CT — The regional nonprofit environmental organization Save the Sound Tuesday released findings of its 2026 Long Island Sound Report Card.

The water quality grades reflect ecological health based on data collected during the most recent full monitoring season in 2025, the four-decade-old non-profit noted.

Subscribe

"The biennial report brought very welcome news, as nearly every section of the open waters of Long Island Sound
demonstrated higher scores compared with the previous report card, even in the most populated areas of New York City," the Sound's protector noted.

But, it pointed out, that the set of grades for individual bays in the Sound "offered reasons for concern due to localized conditions."

Here's how evaluating the state of the LI Sound works:

Save the Sound compiles water quality grades for five segments of the Sound's open waters, stretching the full length of the Sound from the East River at Hell Gate between Manhattan and Queens to Fishers Island off the Connecticut coast. Each of the five segments either increased or maintained their grade versus the 2024 Long Island Sound Report Card.

Open water grades are generated from data collected by the Connecticut Department of Energy and Environmental Protection, the Interstate Environmental Commission, and the New York City Department of Environmental Protection and are formulated by analyzing dissolved oxygen, chlorophyll a, water clarity, and dissolved organic carbon water quality indicators.

2026 Long Island Sound Report Card Grades: Open Waters

• Western Narrows: Improved from F to D, demonstrating an improving trend and receiving a passing grade for the first time in 18 years of grading
• Eastern Narrows: Received a B, demonstrating an improving trend and maintaining its B from the 2024 Report Card
• Western Basin: Improved from A- to A, still variable over the 18-year trend
• Central Basin: Improved from A to A+, remained stable over the 18-year trend
• Eastern Basin: Received an A+, remained stable over the 18-year trend

Save the Sound credited decades of regional efforts, including billions of dollars of upgrades to Connecticut and New York wastewater treatment plants to reduce the levels of nitrogen
entering Long Island Sound, as a leading factor in improved open water grades.

"The reduction in nitrogen entering Long Island Sound has led to significant improvements in water quality," Peter Linderoth, Save the Sound director of healthy waters and lands, is quoted as saying. "It's crucial that we expand on these efforts, as the effects of climate change, including rising water temperatures and worsening stormwater runoff, remain real threats to water quality."

Linderoth noted reducing nitrogen is a priority.

"These challenges have the potential to reverse many of the gains we've made in the open waters," he said. "Nitrogen reduction efforts in many bays and harbors must now be fully prioritized to see similar progress."

Read more here.

About Save the Sound

Save the Sound leads environmental action in Connecticut, Westchester, NYC, and Long Island. We protect the Sound and its rivers, fight climate change, save endangered lands, and work with nature to restore ecosystems. What makes us unique is the breadth of our toolkit and results, from advocacy and legal action to engineering, environmental monitoring, and hands-on volunteer efforts.

For more than 40 years we've been ensuring people and wildlife can enjoy the healthy, clean, and thriving environment they deserve—today and for generations to come.

Learn more at savethesound.org.