Somerville High School Outreach
Presentations on combined and separated sewer systems and citywide flooding.
Related precursor outreachUpdated CSO Control Plan
Planning & Engagement Timeline
The April 30, 2026 Draft followed more than four years of technical development, regulatory coordination, public meetings, watershed engagement, community outreach, and written input. MWRA, Cambridge, and Somerville are the CSO Planning Partners responsible for the joint Draft. The public comment period remains open through October 30, 2026.
New to CSOs? A combined sewer overflow (CSO) can occur when wet weather overwhelms an older combined sewer system carrying sewage and stormwater in the same pipes, causing excess flow to discharge to a nearby waterway. Start with the CSO Resources Hub.
4+Years of Plan DevelopmentFormal process began in 2022
6Pre-Draft Public MeetingsPlus a dedicated Listening Session
6Watershed MeetingsIncluding focused notification meetings
29Community EventsPublished outreach count
19EPA / MassDEP MeetingsReported during Draft development
Timeline at a glance
Public review now underway after more than four years of plan development
4+ years developing the Draft
Technical work, alternatives evaluation, affordability analysis, regulator coordination, and public engagement all fed into the April 2026 filing.
6 Public Meetings
6 Watershed Meetings
29 Community Events
19 EPA / MassDEP Meetings
7 Surveys & Questionnaires
Draft public review
Public Meeting #7, office hours, hearings, library copies, and written comments continue the review after filing.
Final Plan preparation
Comments are reviewed and the Final Updated CSO Control Plan is prepared for January 31, 2027.
Overview segments are weighted for readability; milestone dates above show the actual schedule.
Full record
Planning and Engagement Over Time
- Major milestones remain visible throughout the timeline.
- Select one or more filters to emphasize different forms of engagement.
2021 · RELATED PRECURSOR
2022
April 1, 2022
Formal Updated CSO Planning Begins
MWRA, Cambridge, and Somerville submit Updated CSO Control Plan scopes to MassDEP and EPA.
Public Meeting #1
Introduction to the planning process and schedule.
226 participants recordedJuly 22, 2022 · MassDEP approves the submitted planning scopes.
Public Meeting #2
Project goals, approach, and development of the future 2050 Typical Year.
177 participants recorded · 86 questionnaire responses2023
Recurring EPA / MassDEP coordination
The Partners report ongoing agency coordination throughout Plan development.
19 meetings reportedCommunity-Event Outreach Expands
Project information is shared at events including CX Summer Nights, July 4th Pops, the Cambridge 5K, and other community activities.
Multiple documented outreach events2023 · Climate-informed Typical Year, unified modeling, technology screening, and evaluation criteria develop.
Watershed Advocacy Meeting #1
CSO-control technologies, future rainfall modeling (the 2050 Typical Year), and preview of Public Meeting #3.
21 participants recordedPublic Meeting #3
Technology toolbox and stakeholder values used to help develop evaluation criteria.
243 participants recorded · 81 live-survey responsesOpen Questionnaire Following Public Meeting #3
A month-long public questionnaire collected additional input following the meeting.
1,312 responses2024
Watershed Advocacy Meeting #2
Alternatives-development process, tools under consideration, and mapping exercise.
32 participants recordedCommunity Outreach Continues
Outreach continues at Fresh Pond Day, Cambridge Arts River Festival, SomerStreets, Pride Flotilla, and other documented events.
Multiple documented outreach eventsAugust 30 / September 1, 2024
New Five-Year CSO Variances Issued and Take Effect
The Variances formalize Updated Plan requirements, public participation and environmental justice outreach, affordability analyses, and Draft/Final Plan milestones.
Focused Watershed Meeting — Real-Time Notification
Input on notification in flood-prone areas and the feasibility-study scope.
25 participants recordedWatershed Advocacy Meeting #3
Alternatives progress, cost assumptions, and preview of Public Meeting #4.
35 participants recorded2025
Public Meeting #4
Alternatives development and affordability methodology.
355 participants recorded · 167 live-survey responsesDedicated Listening Session
Designed specifically to solicit concerns, advice, and priorities.
173 participants recorded · 88 survey responsesFocused watershed meeting — notification
Notification requirements, research findings, options, and public education.
20 participants recordedMid-2025 · Affordability analysis, review and narrowing of project alternatives, water-quality modeling, scoring, and siting continue.
Continued Community-Event Outreach
Run of the Charles, Port Arts Festival, Dragon Boat Festival, Pride Flotilla, July 4th Pops, CX Summer Nights, SomerStreets, and other documented activities.
Multiple documented outreach eventsWatershed Advocacy Meeting #4
Alternatives analyzed, evaluation criteria, preliminary scoring, and water-quality modeling.
29 participants recordedPublic Meeting #5
Preview of alternatives under consideration.
198 participants recorded · 70 live-survey responsesFall 2025 · Board review, Partner cost-allocation discussions, and recommended-plan development intensify.
December 31, 2025
Original Draft Plan deadline
Shown for context. The deadline was extended 120 days to April 30, 2026.
2026
Public Meeting #6
Requested filing extension, potential recommended alternatives, water quality, construction, cost, and rate information.
359 participants recorded · 140 survey responsesApril 30, 2026
Draft Updated CSO Control Plan Filed
A major milestone after more than four years of formal planning, technical analysis, regulator coordination, and engagement.
Draft Made Broadly Available
Online access plus physical copies in libraries throughout all 43 MWRA sewer-service communities and the MWRA Chelsea library.
Public Meeting #7
Draft Plan contents and how to participate in the public-comment process.
Office Hours Across the Service Area
Virtual and in-person opportunities in Boston, Somerville, and Cambridge.
8 documented past sessionsAugust 11, 2026
Public-Comment Period Extended
MassDEP extends the deadline by 30 days, from September 30 to October 30, after public requests and consultation with the Partners.
Public Hearing #1
Hybrid hearing in Cambridge; oral comments entered into the public record.
CompletedTODAY · SEPTEMBER 24, 2026
36
Days left to commentComments close Oct. 30, 2026
How to commentPublic Hearing #2
Virtual public hearing.
PLANNEDProject page & meeting information
September 30, 2026
Original Public-Comment Deadline
Superseded by the 30-day extension.
Somerville Office Hours
In-person public access session.
PLANNEDProject page & meeting information
Public Hearing #3
Hybrid public hearing in Somerville.
PLANNEDProject page & meeting information
October 30, 2026
Revised Public-Comment Deadline
End of the extended public-comment period.
2027
January 31, 2027
Final Updated CSO Control Plan Due
The governing 2024 Variances require submission of the Final Plan for Massachusetts Environmental Policy Act (MEPA) review.
Public & Watershed Engagement Record
A different way to inspect the record: participation and input, documented effects where the source record makes the connection, status, and source references in one place.
| Date | Event | Type | Participation / input | Documented effect of input | Status | Source |
|---|---|---|---|---|---|---|
| Jun. 29, 2022 | Public Meeting #1 | Public meeting | 226 participants recorded | — | Completed | Draft Plan, Table 5-4 |
| Dec. 15, 2022 | Public Meeting #2 | Public meeting | 177 participants recorded; 86 questionnaire responses | — | Completed | Draft Plan, Tables 5-4 & 5-7 |
| Oct. 24, 2023 | Watershed Advocacy Meeting #1 | Watershed | 21 participants recorded | — | Completed | Draft Plan, Table 5-5 |
| Nov. 15, 2023 | Public Meeting #3 | Public meeting | 243 participants recorded; 81 live-survey responses | — | Completed | Draft Plan, Tables 5-4 & 5-7 |
| Dec. 12, 2023–Jan. 15, 2024 | Open Questionnaire Following Public Meeting #3 | Written public input | 1,312 responses | — | Completed | Draft Plan, Table 5-7 |
| Jun. 24, 2024 | Watershed Advocacy Meeting #2 | Watershed | 32 participants recorded | — | Completed | Draft Plan, Table 5-5 |
| Nov. 20, 2024 | Focused watershed meeting — notification | Watershed | 25 participants recorded | — | Completed | Draft Plan, Table 5-6 |
| Dec. 17, 2024 | Watershed Advocacy Meeting #3 | Watershed | 35 participants recorded | — | Completed | Draft Plan, Table 5-5 |
| Jan. 22, 2025 | Public Meeting #4 | Public meeting | 355 participants recorded; 167 live-survey responses | — | Completed | Draft Plan, Tables 5-4 & 5-7 |
| Apr. 3, 2025 | Dedicated Listening Session | Public engagement | 173 participants recorded; 88 survey responses | Listening Session was added to the engagement framework at the suggestion of watershed advocacy groups. | Completed | Draft Plan, §5.3.2.1 / Table 5-4 |
| May 5, 2025 | Focused watershed meeting — notification | Watershed | 20 participants recorded | — | Completed | Draft Plan, Table 5-6 |
| Sep. 4, 2025 | Watershed Advocacy Meeting #4 | Watershed | 29 participants recorded | — | Completed | Draft Plan, Table 5-5 |
| Sep. 25, 2025 | Public Meeting #5 | Public meeting | 198 participants recorded; 70 live-survey responses | Part of additional public engagement addressing requests for greater transparency around alternatives and scoring. | Completed | Draft Plan, §5.4 / Table 5-9 |
| Jan. 15, 2026 | Public Meeting #6 | Public meeting | 359 participants recorded; 140 survey responses | Additional meeting was added in response to feedback seeking greater transparency during alternatives review. | Completed | Draft Plan, Table 5-4 |
| Jun. 2, 2026 | Public Meeting #7 | Public meeting | Attendance not yet locked | Opened the post-filing review phase and explained how to submit comments. | Completed | Joint project page |
| Sep. 17, 2026 | Public Hearing #1 | Public hearing | — | Oral comments entered into the formal public record. | Completed | Joint project page |
| Sep. 24, 2026 | Public Hearing #2 | Public hearing | — | Scheduled opportunity for oral public comment. | Planned | Joint project page |
| Oct. 28, 2026 | Public Hearing #3 | Public hearing | — | Scheduled opportunity for oral public comment. | Planned | Joint project page |
Meeting counts are event-level participant counts from the source record; totals across events should not be read as unique people because the same person may participate more than once. Blank effect fields mean the source record does not make a direct input-to-response connection for that entry. Source links open the persistent joint-project page rather than temporary meeting URLs.
