The Massachusetts Water Resources Authority (MWRA) provides water and sewer services to 61 municipalities in the Metropolitan Boston area and west of Boston. If your facility is in an area served by the MWRA for sewer discharge, for many permit holders, MWRA sampling is required by June 30, 2026 and a semi-annual report is due by July 31, 2026.
Semi-Annual Sampling
Although holders of a General Permit for Low Flow/Low Pollutant Discharge are exempt, semi-annual sampling is a requirement for most facilities that have a Category 2 MWRA permit.
The sample analysis must be performed by an independent laboratory that is either certified by the Massachusetts Department of Environmental Protection (MassDEP) or accredited under the Environmental Protection Agency’s (EPA) National Environmental Laboratory Accreditation Program (NELAP). Unless otherwise authorized by the MWRA or EPA, the process must be conducted in accordance with applicable EPA-approved procedures [40 CFR Part 136]. Appropriate chain-of-custody documentation, demonstrating proper handling during sample collection, transport, and receipt by a certified laboratory, must be included as well. Both the permit holder and the testing laboratory have specific responsibilities.
The permit holder is required to:
- Provide a Sample Analysis and Reporting Certification Form to the MWRA if a current copy is not already on file. This form authorizes the laboratory to submit analytical results electronically. A copy of the form is available in the facility’s MWRA permit and on the Toxic Reduction and Control (TRAC) website.
- Review sampling results promptly upon receipt and notify their local MWRA Industrial Coordinator (IC) of any non-compliance issues.
The analytical testing laboratory must:
- Submit wastewater sampling results directly to the MWRA through the electronic Pretreatment Information Management System Web Self-Monitoring Report (Web SMR).
- Provide the permittee with a copy of the results no later than the day they are submitted to the MWRA.
The Sewer Use Regulations [360 CMR 10] establish daily maximum discharge limits for regulated pollutants including formaldehyde, cyanide, phenol, specific metals, and listed toxic organics for both the Metropolitan and Clinton Sewerage Service Areas.
If the sampling results exceed the limits specified in the facility’s permit or the regulations, the MWRA must be notified at 617-242-6000 within 24 hours of becoming aware of the violation. A report documenting the non-compliant discharge must also be submitted.
The permit holder must repeat the sampling and analysis and submit a follow-up report to the MWRA within 30 days. Prior to resampling, the permit holder should investigate the cause of the violation, identify the source, and take corrective actions to prevent recurrence.
Sampling analyses records must be maintained on-site for at least 3 years.
Semi-Annual Report
In addition to sampling, Category 2 permit holders are required to submit a semi-annual report by July 31, 2026. This report must include pH and flow logs covering the period from January through June. The logs must record the daily discharge volume (gallons per day) and identify any days when the pH values fall outside the acceptable range (5.5 – 12.0 s.u.), resulting in a violation.
For each pH excursion, the most extreme pH value and the duration of the event must be documented in the log. In the comments section, a brief explanation of the cause and the response is required. Information listing when the neutralization system is malfunctioning or under repair (e.g., when the pH recorder isn’t operable due to probe maintenance) and for how long must also be included.
Each entry must be initialed by the person recording the data. The logs must be submitted as part of the semi-annual report using the MWRA Submittal Form, which is available in the permit and on the TRAC website. The form is completed by selecting the appropriate submission type and including:
- Company name and address.
- MWRA permit number and sample location number.
- Due date of materials being submitted.
If no discharge occurred during the sampling period, a Submittal Form must still be completed by selecting the “Notice of Location Not Discharging During Sampling Period” option. Additionally, a letter must be provided to the MWRA explaining why there was no discharge and if the condition is permanent.
How Safety Partners Can Help
Safety Partners can simplify your compliance obligations by assisting with:
- Scheduling required sampling with an approved vendor.
- Reviewing and interpreting sampling results, and making required notifications to the MWRA.
- Investigating the reasons for non-compliant discharges and helping implement corrective actions.
- Coordinating any necessary resampling.
- Reviewing pH and flow logs for compliance.
- Preparing and submitting the semi-annual report and MWRA Submittal Form.
- Supporting MWRA record keeping requirements.
Contact us for more information on your semi-annual sampling and reporting obligations, other MWRA requirements, and the services we provide to help ensure compliance.
This blog was written by Beth Graham, Safety Partners’ Director of Quality, Research, and Training.
