Link to MWRA Home Page

Boston Harbor and Massachusetts Bay
MWRA Environmental Quality

Harbor & Bay

MWRA Monitors the Harbor & Bay

The Massachusetts Water Resources Authority 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 permit compliance page


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 Massachusetts Bay page

MWRA monitors in Massachusetts Bay to assess the impacts of sewer system and treatment plant discharges. Parameters measured are nutrients, organic material, toxic contaminants, pathogens, bacteria, and solids. There is also monitoring in Cape Cod Bay.

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 Harbor beaches page BEACH TESTING

In summer, bacterial pollution is monitored and bacteria counts are measured regularly at Harbor beaches.

Go to the Harbor beaches page

Download beach data