Boston Harbor is an estuary--a marine ecosytem where fresh water from the rivers enters the ocean. Since 1989, the Massachusetts Water Resources Authority (MWRA) has measured bacteria, algae, water clarity, dissolved oxygen, nutrients, and suspended solids at more than 70 locations in the Harbor and the Charles, Neponset, and Mystic rivers.
Boston Harbor and River Monitoring Data
Detailed sampling location map
Boston Harbor Beach Data
Water quality at Wollaston, Carson, Constitution,
Tenean and Pleasure Bay beaches is tested by the Department of Conservation
and Recreation (DCR) with assistance from the Massachusetts Water Resources Authority. For more information and other beach water quality links, visit MWRA's Boston Harbor Beaches page.
Historical Beach Data
Massachusetts Bay bacteria monitoring
How we manage water quality data