Link to MWRA Home Page


Boston Harbor and Massachusetts Bay
MWRA Environmental Quality


MWRA monitors the water quality of Boston Harbor and Massachusetts Bay, measuring nutrients, pathogens, metals, organics, solids, pH, oil and grease, and toxicity. See the What's New page for the latest water quality information and reports.


Link to Massachusetts Bay page

MWRA monitors in Massachusetts and Cape Cod Bays to assess the impacts of sewer system and treatment plant discharges. Watch underwater video.

More about outfall monitoring results

Go to the Massachusetts Bay page

Link to Boston Harbor page HARBOR AND RIVER SAMPLING

Nutrients, pathogens, dissolved oxygen, temperature & water clarity are measured in Boston Harbor and its tributary rivers.

Go to the Boston Harbor page

Download historical Harbor & river data

Link to permit compliance page ENVIRONMENTAL COMPLIANCE

MWRA's NPDES discharge permit requires compliance reports on several measures of effluent quality and system maintenance. This is intended to control water pollution and ensure compliance with the federal Clean Water Act.

See the most recent permit compliance reports

Link to Harbor beaches page BEACH TESTING

In summer, bacteria counts are measured regularly at Wollaston, Carson, Constitution, Tenean and Pleasure Bay beaches.

More about Beach Monitoring results

Go to the Harbor beaches page

Download beach data