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Boston Harbor and Massachusetts Bay
Massachusetts Water Resources Authority

NPDES Permit

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. MWRA is required by the permit to post the following compliance reports and related information online.

What's New Links to recent MWRA treatment plant performance and environmental quality reports.
Ambient Monitoring Reports on monitoring in Massachusetts Bay.
Best Management Practices To keep each facility's operation clean so it does not become a polluter.

Contingency Plan

MWRA developed this plan to ensure that discharge from the outfall does not result in adverse impacts to the Bay. The Plan identifies thresholds that can suggest that effluent quality or conditions in the Bay may be changing. "Caution" or "Warning" level exceedances of Contingency Plan thresholds for water quality monitoring in Massachusetts Bay. Designed to detect potential effects of the outfall.
Discharge Monitoring Compliance reports on the quality of effluent being discharged into Massachusetts Bay. See also Deer Island Treatment Plant Performance reports.
Combined Sewer Overflow (CSO) Variance MWRA has been granted a variance from having to meet water quality standards in the Charles River and Alewife Brook/Upper Mystic River. A plan is being implemented to reduce the impacts of combined sewer overflows.
Flow Limitation Demand management and water conservation efforts designed to minimize flows to the Deer Island Treatment Plant. The NPDES permit contains an average dry day flow limit of 436 MGD. Each year, MWRA must submit a report describing demand management programs and water conservation efforts that are being pursued with communities in the service area. The annual report must assess the effectiveness of demand management measures as well as identify planned activities.
Groundwater Remediation MWRA prohibits discharges into the MWRA system for groundwater remediation activities. Any proposed changes to this rule must be posted onine.

Local Limits

A review of MWRA standards and limits for discharges from certain business or industrial sewer users. MWRA regulates discharges from certain business or industrial sewer users and prescribes standards and limits for both the quantity and quality of substances that may be discharged. The permit requires MWRA to develop and enforce these limits to prevent pollutants from being introduced into the system that could interfere with the operation or performance of the works, or cause problems with NPDES compliance or sludge disposal practices.

Operations & Maintenance (including Infiltration & Inflow)

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 submit a summary report of all actions taken to reduce infiltration/inflow during the previous fiscal year. Government regulators must also be notified when there is an operational incident or upset at an MWRA facility.
OMSAP Meetings The Outfall Monitoring Science Advisory Panel (OMSAP) advises the US Environmental Protection Agency and the Massachusetts Department of Environmental Protection on scientific and technical matters related to MWRA's bay outfall and any potential impacts of the discharge on its receiving waters.

Pollution Prevention

MWRA must submit to regulators a comprehensive pollution prevention plan that addresses households and industries discharging in MWRA's sewer service area. The plan includes steps for identifying and controlling sources of PCBs, and for containing chemical spills.

Published by MWRA's Toxic Reduction And Control (TRAC) Department, the Industrial Waste Report documents MWRA’s ongoing efforts to implement the requirements of 40 CFR Part 403, General Pretreatment Regulations. A Healthy Environment Starts at Home is a guide to hazardous household substance.

Prior Notice MWRA must provide at least a 30-day written prior notice to the public, EPA and DEP, the National Marine Fisheries Service and the Outfall Monitoring Scientific Advisory Panel and its two advisory committees of any significant change in the volume or character of pollutants being introduced into the treatment plant that may cause the discharge to lead to an exceedance of water quality standards in the receiving water.
Archive All reports are available to those who want historical information.