On April 3, 2025, the MWRA Advisory Board participated in a public listening session hosted by the Massachusetts Water Resources Authority (MWRA), the City of Somerville, and the City of Cambridge to discuss the updated Long-Term Control Plan (LTCP) for Combined Sewer Overflows (CSOs). This plan outlines billions of dollars in proposed new infrastructure investments for the Charles River, Alewife Brook, and Mystic River watersheds, with the goal of further reducing or treating sewer overflows during wet weather.
As the financial watchdog for 43 sewer MWRA communities, the Advisory Board’s role in the session was to provide context, ask hard questions, and ensure that new investments are both effective and equitable. We support clean water and have long advocated for environmental improvements—but we also believe every dollar spent should produce a meaningful return in water quality and public health benefits.
A Look Back: What the Original Plan Accomplished
The original CSO control plan, using 1992 system conditions as its baseline, set out to address nearly 1.5 billion gallons of annual overflow. Through decades of work and a $1.52 billion investment (adjusted for inflation), the system has eliminated more than 1 billion gallons per year of untreated CSO. The result? A transformed Boston Harbor, a cleaner Mystic and Charles, and thriving waterfront neighborhoods.
That investment brought the current CSO volume down to 401 million gallons per year. It also funded construction and upgrades to multiple detention and treatment facilities — including sites in Boston, Cambridge, and Somerville — that now capture and disinfect the majority of what remains. The original plan wasn’t just a success — it was a national model for urban water quality recovery.
A New Lens: Dollars per Gallon Managed
With the updated plan now projected to cost up to $4.7 billion and focused on controlling less than 200 million gallons per year, the Advisory Board introduced a new way of thinking: What’s the cost per gallon of overflow addressed?
Under the original plan, we spent about $1.44 per gallon eliminated (in today’s dollars). The updated plan, by comparison, would cost more than $23.50 per gallon (also in today’s dollars).
We believe it’s fair to ask: Is this the best use of limited ratepayer funds? Does it deliver a proportional return in public health and water quality?
New Challenges, Bigger Price Tag
There’s no doubt the updated plan faces harder engineering problems. We’re now trying to design infrastructure to manage rare, extreme storms—what’s known as a 25-year storm event. Solutions like deep tunnels and massive storage tanks are expensive, slow to build, and disruptive to local communities.
Climate change also adds uncertainty. In dry years, CSO volume may be minimal. In wet years, it spikes. Should we lock in billions of dollars now without first exploring more flexible or adaptive approaches?
Our Position: Support Progress, Insist on Smart Spending
The Advisory Board fully supports continued progress in water quality. But we believe future investments must be:
- Strategic: Focus on the highest-impact projects
- Fair: Ensure costs are distributed appropriately across MWRA and satellite communities
- Efficient: Maximize the water quality and public health benefit of every dollar
- Flexible: Allow room to adapt as climate, development, and science evolve
Some voices have questioned whether cost considerations mean we don’t care about clean water. We want to be clear: we do care. We care enough to ask tough questions—because spending wisely is a public health strategy.
What’s Next
We look forward to continued dialogue with communities, environmental advocates, regulators, and MWRA leadership. Our goal remains the same: ensure that the next generation of investments is smart, equitable, and sustainable for the people who ultimately pay for it.
📊 View full presentation here
