Long Island Sound Water Quality Shows Improvement, Report Indicates

A report by Save the Sound indicates that improvements in water quality in the Long Island Sound are linked to billions of dollars in wastewater and infrastructure upgrades across Connecticut and New York. The 2026 Long Island Sound Report Card reveals that water quality has improved or remained stable in all five open-water regions of the Sound. The Western, Central, and Eastern basins received A grades, while the Eastern Narrows received a B. The Western Narrows, which includes waters around New York City, improved to a D grade, marking the first passing grade since grading began in 2008. Previously, it had received an F each year. The Western Basin improved from an A- to an A, and the Central Basin improved from an A to an A+. The Eastern Basin maintained its A+ grade, and the Eastern Narrows remained at a B. Water quality assessments are based on factors such as dissolved oxygen, chlorophyll, water clarity, and dissolved organic carbon. Excess nitrogen, which can lead to harmful algae blooms, has been identified as a significant factor affecting water quality. Save the Sound noted that reducing nitrogen entering the Sound has contributed to the observed improvements. The Unified Water Study, initiated in 2017, aims to enhance understanding of water quality in 52 bays and harbors of the Sound through standardized monitoring. While the findings are positive, Save the Sound cautions that climate change, rising water temperatures, and increased stormwater runoff could threaten progress. Continued efforts to reduce nitrogen pollution and invest in infrastructure are deemed essential for maintaining improvements.