and Massachusetts Bay
MWRA Environmental Quality
The latest Environmental Quality and Compliance Reports
The Massachusetts Water Resources Authority
has been granted a federal National Pollutant Discharge Elimination
System (NPDES) permit to discharge effluent from the Deer Island
Wastewater Treatment Plant into Massachusetts Bay. As required by its permit, MWRA must post
many water quality reports online.
Use the drop-down menu
to view reports required by
MWRA's discharge permit.
Monthly monitoring results from DITP and Combined
Sewer Overflow facilities are summarized in these tables
submitted to regulators. (PDF)
Plant Performance Report (PDF)
Most recent data on the DITP effluent discharges.
Monitoring at the Mass. Bay Outfall: Measurements of fecal coliform and Enterococcus in Massachusetts Bay.
List of ambient monitoring reports published in the last quarter. Includes links to technical reports and other required documents.
Contingency Plan Report
on Ambient Monitoring (PDF)
Monitoring data compared with threshold limits in MWRA's Contingency
Plan Report on Effluent Monitoring (PDF)
Summary of data on pH, fecal coliform, toxicity, oil and grease, and nitrogen
in DITP effluent compared
with limits in the Contingency Plan.
Outfall Monitoring Overview (PDF) See highlights
Report - Assurance of Compliance with 436 MGD Flow Limit (PDF)
Annual Report on Infiltration
and Inflow (PDF)
Annual Status of Plant Maintenance (PDF)
Contingency Plan Exceedance Reports
Notices of treated discharges at the Cottage Farm CSO outfall to the Charles River
Web Water Quality Reports (archive)