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Boston Harbor and Massachusetts Bay
Massachusetts Water Resources Authority

Operations & Maintenance

MWRA performs routine maintenance of the sewer system, the sewage treatment plant, and the sludge pelletizing plant. MWRA must submit annual status reports on maintenance activities to EPA and DEP, and place this information on this website. MWRA is also required to submit a summary report of all actions taken to reduce infiltration/inflow during the MWRA's past fiscal year. The report includes community wastewater flows and estimated reductions in infiltration and inflow for MWRA service area communities. Government regulators must also be notified when there is an operational incident or upset at an MWRA facility.

Infiltration & Inflow

Deer Island Treatment Plant Maintenance

Combined Sewer Overflow (CSO) postings

Operational Notifications

Many of our reports are in PDF format, which requires Adobe Acrobat Reader®, a free program available from Adobe Systems. To request a paper copy of any report, please contact the MWRA Environmental Quality Department at 617-788-4601, or e-mail us at

Questions? Email the Environmental Quality Department