MWRA Was Created to Solve This Regional Problem & Using Its Funding Lowers the Total Cost

The Origins of the MWRA

In 1984, as a result of the Boston Harbor Cleanup Court Case, the Legislature created the Massachusetts Water Resources Authority to tackle the region’s greatest environmental crisis – sewage pollution, sewer infrastructure failures, and decades of mismanagement. Under the glare of the national spotlight during the Bush vs. Dukakis campaign, and with the legal muscle of the Conservation Law Foundation and USEPA in federal and state courts, the state legislature created the MWRA. The Legislature empowered MWRA with a dedicated funding mechanism for infrastructure upgrades.

The MWRA Enabling Act of 1984^[1] mandates the “repair, replacement, rehabilitation, modernization and extension” of the sewer system, “in the best interests of the commonwealth and its inhabitants, to promote the general health and welfare, to improve commerce and living conditions of the citizenry.”

Through borrowing backed by water and sewer system revenues, with rate increases throughout the 1980s and 90s^[2], the MWRA raised $5 billion, funding the construction of the Deer Island Treatment Plant and reducing combined sewer overflows. The result has been a $100 billion return in public health, environmental recovery, and real estate value. This is the story of one of the Clean Water Act’s greatest environmental successes in the United States.

CSOs are a Regional Problem of a Connected Sewer System

Map of the Chelsea Creek Headworks Service Area provided by the Massachusetts Water Resource Authority.

MWRA owns aging regional sewer system infrastructure which ties Cambridge and Somerville to MWRA’s regional system at Alewife Brook. MWRA’s infrastructure at Alewife Brook includes two large “interceptor” pipes built in 1896 and 1948. Those interceptors are connected to all six Alewife Brook CSO outfalls, as well as the Alewife Brook Pump Station. The Alewife Brook Pump Station is the oldest operating pump station in the MWRA’s system.

Stormwater in the combined systems regularly overload the MWRA’s sewer system during wet weather storm events, sometimes when the area gets less than an inch of hard rain. At MWRA’s February 22, 2022, public briefing to discuss the Final Combined Sewer Overflow Performance Report, MWRA’s consultant from AECOM stated, “The MWRA system is limited by downstream capacity. Under very large storm events, the capacity of the Alewife Brook Pump Station, which is downstream of [MWR003] is reaching capacity – very large facility, has 90 million gallons per day capacity. That then discharges into sewers conveying flow further downstream and going to the Chelsea Creek Headworks, that then reaches capacity. And there are events when the capacity of our Deer Island treatment plant, 1.2 / 1.3 billion gallons per day, is reached. So there are limits to what the MWRA can push through the system.”

The regional sewer system simply cannot move the stormwater in the system during many storms. Raw sewage mixed with stormwater from Cambridge and Somerville discharges into Alewife Brook because it has nowhere else to go.

Open Sewers are Part of MWRA’s Sewer Strategy

MWRA’s 2018 Wastewater Masterplan states that CSOs provide “additional system capacity”.^[3] For MWRA, CSOs are a feature of its system that is overburdened by an increasing amount of stormwater from increasing amounts of precipitation due to Climate Change. With 6 active raw CSO outfalls at Alewife Brook, MWRA, Cambridge, and Somerville use Alewife Brook as an open sewer.

From MWRA’s 2018 Wastewater Masterplan. MWRA views CSOs as “additional capacity” to their system.

MWRA’s Annual Revenue

MWRA’s 2026 budget is $922 million. 95% of its revenue comes from ratepayer money – that includes over a million households and businesses paying water and sewer bills to their municipalities.

$2.1 billion funding available,
without a shock to households and at low interest rates

MWRA uses its revenue to back long-term bonds to fund sewer system upgrades at more favorable interest rates than cities, Massachusetts, or even the federal government. Decades ago, MWRA issued billions of dollars in bonds to pay for the Harbor Cleanup CSO projects and the Deer Island treatment plant. Those bonds are now expiring, meaning they are paid off. In the next ten years, MWRA has the capacity to issue another $2.1 billion in bonds.^[4] MWRA’s revenue remains the same, steadily increasing by 3-4% annually, so the budget already exists for the debt service on new bonds. Thus, there will be no huge shock to the ratepayers on their sewer bills.

MWRA’s Legal and Financial Responsibility

According to the Boston Harbor Court Case’s Second Stipulation^[5], MWRA is legally and financially responsible for combined sewer overflows that are in violation of the Boston Harbor court case.

As of 2026, the following untreated CSO outfalls remain in violation of the court order,^[6] as these outfalls do not meet the required levels of control mandated by the court:

From MWRA’s 12/27/2024 Supplement to the 2021 Final Combined Sewer Overflow
Post Construction Monitoring Program and Performance Assessment Report^[7]

Six CSO outfalls (SOM001A, CAM401A, CAM005, MWR018, MWR019, BOX003) that are in violation of the court order discharge untreated sewage, making them considerably more hazardous to community health than treated CSOs.

Other outfalls in the MWRA system are not in compliance with the court order, but are expected to meet the court order by the end of this year. That includes Somerville’s treated CSOs at Mystic River.

According to the Court’s Second Stipulation, the MWRA is responsible for funding infrastructure work on these outfalls to comply with the Court Order. Using the MWRA to fund as much of these plans as possible lowers the cost and accurately reflects the regional nature of these challenges. Some costs may fall on the cities as well. For example, the cities may have additional costs related to complete streets and stormwater infrastructure when doing sewer separation work.

MWRA should cover costs for all legally required work. Additionally, the legislature should seriously consider expanding the scope of the MWRA through updated enabling legislation. Stormwater is an unavoidable part of solving CSOs and managing our regional water infrastructure more generally.

MWRA’s Own Affordability Analysis:
At the cost of $46 more per year to households,
MWRA can afford to eliminate sewage in the Alewife, Charles, Mystic.

MWRA’s February 2026 financial analysis^[8] shows that the difference in household sewer bills between the least and most expensive plans – which would virtually^[9] eliminate sewage pollution in the Charles, Mystic, and Alewife – is minimal, roughly the cost of a cup of coffee per month.

The difference in cost annually to households between the bare minimum CSO plan, called “0 CSOs in the 2050 Typical Year”, and the most expensive plan, called “0 CSOs in the 2050 25-year” is $82 in 2050. That is equal to $46 in 2025 dollars, using MWRA’s assumed rate of inflation at 2.5%

MWRA’s Senseless Demand of “Cost Sharing” with Cambridge and Somerville

In the meeting materials shown below from the February 25, 2026, MWRA Board of Directors meeting,^[10] a staff note from MWRA’s Executive Director Fred Laskey proposed that the cities of Cambridge and Somerville pay a total of $516 million for the CSO control plans.

MWRA Executive Director Fred Laskey proposes that Cambridge and Somerville contribute a total of $516 million to the CSO Control Plan, which includes Alewife Brook and the Charles and Mystic Rivers.

However, according to the court case’s Second Stipulation^[11], the cities do not have to contribute funding towards projects involving the two Alewife CSO outfalls that are in violation of the Court. The two Alewife Brook CSOs that are in violation of the court are the Alewife MBTA Station CSO (CAM401A) and the Davis Square Tannery Brook CSO (SOM001A).

The cities are not responsible for the cost. MWRA has asked Boston to pay nothing, which is correct because Boston has been aggressively preparing for Climate Change with sewer separation in East Boston. Like Boston, Cambridge and Somerville have been aggressively investing in sewer separation. As a regional entity, MWRA should pay for regional solutions. MWRA is legally responsible for paying for infrastructure upgrades associated with the CSOs that are in violation of the court order. MWRA needs to begin investing now in removing stormwater from its regional sewer system, in preparation for Climate Change.

MWRA Funds Available Now:
Cities Must Act Now or Forfeit System Upgrades Funding

Now is the last time that the cities of Cambridge and Somerville are able to use MWRA’s funding as required by the Harbor court case to cover the cost of sewer infrastructure upgrades. It is the region’s best interest to remove stormwater from the combined systems now through sewer separation. The cities should be pushing for the most ambitious plan to modernize their 19th century sewer systems now. To do otherwise would be fiscally irresponsible. It will never be cheaper to do this work than it is now. Climate Change demands an investment in sewer separation and Green Stormwater Infrastructure now.

Footnotes:

1. MWRA Enabling Act, Chapter 372 of the Acts of 1984: https://www.mwra.com/about-mwra/governance-management/enabling-act ↑

2. Paul Levy’s Financing the Boston Harbor Project: https://www.bscesjournal.org/wp-content/uploads/CEP-Vol-9-No-1-07.pdf ↑

3. MWRA’s 2018 Wastewater Masterplan, page 9: “The Deer Island Treatment Plant (DITP) receives an average daily flow of 353 mgd and has a peak wet weather capacity of 1,270 mgd, with additional system capacity available at combined sewer overflow (CSO) outfalls.” https://savethealewifebrook.org/wp-content/uploads/2022/04/MWRA_wastewatermasterplan_2018.pdf ↑

4. MWRA Annual Report November 2024, Secured Bond Debt Service chart, page 2: https://emma.msrb.org/P11811316-P11388424-P11828155.pdf ↑

5. https://savethealewifebrook.org/wp-content/uploads/2026/02/Second_Stipulation_2006_ocr.pdf Exhibit B, paragraph 4 of the Second Stipulation, MWRA “accepts legal liability to undertake such corrective action as may be necessary to implement the CSO control requirements set forth in Schedule Six and related orders of the Court… and to meet the levels of CSO control.” ↑

6. MWRA’s 12/27/2024 Supplement to the 2021 Final Combined Sewer Overflow Post Construction Monitory Program and Performance Assessment Report, Section 4 Update to the Final Assessment Report – Summary and Conclusions: https://www.mwra.com/media/file/supplementaltofinal122724 ↑

7. MWRA’s 12/27/2024 Supplement to the 2021 Final Combined Sewer Overflow Post Construction Monitory Program and Performance Assessment Report, Section 4 Update to the Final Assessment Report – Summary and Conclusions: https://www.mwra.com/media/file/supplementaltofinal122724 ↑

8. February 4, 2026 MWRA Board Meeting Materials, page 27: “The sewer system annual household charges are currently anticipated to increase from $999 per year to $2,337 per year without the CSO spending between fiscal years 2029 and 2050. In 2050 based on the additional CSO spending, the household charges are projected to increase to $2,380, $2,433 and $2,462 per year for spending associated with level of control to achieve zero CSOs in the 2050 typical year, 2050 5-year and 2050 25-year storms, respectively.” https://www.mwra.com/media/file/2026-02-04-mwra-board-directors-meeting-materials ↑

9. The 2050 0 CSOs 25-Year Storm level of control is the equivalent of CSO elimination. It is the Watershed Associations’ recommended level of control. ↑

10. MWRA Board of Directors Meeting Materials, 02/25/2026: https://www.mwra.com/media/file/2026-02-25-mwra-board-directors-meeting-materials ↑

11. https://savethealewifebrook.org/wp-content/uploads/2026/02/Second_Stipulation_2006_ocr.pdf Exhibit B, paragraph 4 of the Second Stipulation, MWRA “accepts legal liability to undertake such corrective action as may be necessary to implement the CSO control requirements set forth in Schedule Six and related orders of the Court… and to meet the levels of CSO control.” ↑