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The State of Boston Harbor and Massachusetts Bay
MWRA Environmental Quality Department

Harbor and Bay Monitoring


MWRA measures the quality of treated wastewater (effluent) from 43 communities that is discharged through a 9.5-mile outfall tunnel into the deep waters of Massachusetts Bay.

See the What's New page for the latest Harbor and Bay reports.
 
Monitoring Activity
What is measured
Goals
Link to Massachusetts Bay page

MASSACHUSETTS BAY-Outfall monitoring in Massachusetts and Cape Cod bays as required by the NPDES discharge permit.

 Effluent, water column, sea floor, and fish/shellfish samples are collected. Measurements include nutrients, organic material, toxic contaminants, pathogens, and solids.

Assess the impacts of MWRA sewer system and treatment plant discharges on Massachusetts and Cape Cod bays.


Link to Boston Harbor and Rivers page

BOSTON HARBOR & TRIBUTARY RIVERS - Combined sewer overflows (CSOs) are a source of wet weather pollution to Boston Harbor and its tributary rivers. Harbor monitoring tracks contamination from CSOs. CSOs can affect the water quality at Harbor Beaches.

Nutrients, pathogens, dissolved oxygen, temperature, & water clarity in the harbor, Quincy, Hingham, and Dorchester Bays; Charles, Neponset, & Mystic River/Alewife Brook.

Assess CSO impacts on affected water bodies and track environmental effects of pollution reduction efforts.

 
Link to NPDES Discharge Permit Page

NPDES discharge monitoring- Under the National Pollutant Discharge Elimination System (NPDES) permit, MWRA must monitor effluent from the Deer Island Wastewater Treatment Plant (DITP) in Winthrop and several CSO treatment facilities in the metropolitan Boston area.


Nutrients, pathogens, metals, organics, solids, pH, oil and grease and toxicity. (For further explanation of these measures, see the Glossary.)

As authorized by the Clean Water Act, program controls water pollution by regulating point sources that discharge pollutants into water bodies.

 
Link to Technical Reports List

TECHNICAL REPORTS - Effluent, Bay, and Harbor monitoring results are analyzed and summarized in technical reports written by MWRA staff and consultants. Web reports on water quality are also available.

Web reports include Bay bacteria, treatment plant performance, and data on the harbor and bay summarized in the online State of Boston Harbor and Mass. Bay pages.

Provides the latest monitoring results to the public. (Paper copies are available on request.)

See how we manage our water quality data