Why Is the Gowanus Canal Cleanup So Over Budget and Behind Schedule?
The Gowanus Canal’s federal Superfund cleanup now costs more than 13 times its original 2013 estimate and is running over six and a half years behind schedule, according to the EPA’s own Inspector General. The watchdog report points to a specific cause — but it’s not the canal dredging itself. It’s the city’s two underground sewage-retention tanks.
At a Glance
- Original 2013 cost estimate: $78 million. Current cost: more than $1 billion — a 13x overrun.
- The cleanup is running more than 6.5 years behind its original schedule.
- The EPA watchdog report singles out the city’s two CSO retention tanks, not EPA’s own dredging, as the delay it examined.
- The $1.6 billion tank program won’t be fully operational until 2029.
- New towers, Gowanus Green’s affordable housing, and the neighborhood’s own pool all sit downstream of this cleanup finishing.
Two Different Projects, One Superfund Site
“The Gowanus cleanup” is actually two separate projects run by two different agencies. The EPA is dredging and capping the canal itself — the upper segment finished in summer 2024, and a $369 million middle-segment phase has been underway since June 2024.
The city’s Department of Environmental Protection is building the other half: an 8-million-gallon tank at the canal’s head, running underground for nearly two blocks between Butler and Degraw Streets, plus a smaller 4-million-gallon tank further down the canal. Together they’re designed to stop the raw sewage that currently overflows into the canal every time it rains hard — a $1.6 billion program in total, with the larger tank alone costing $329 million.
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What the Watchdog Report Actually Found
The EPA Inspector General’s report on Superfund delays and cost overruns was written specifically about the city’s two tanks — not the EPA’s own canal dredging. It blamed disagreements between EPA and New York City over the cleanup’s Record of Decision, and warned the canal could need a second round of dredging if the delays continue.
DEP says it delivered the tanks’ excavation phase six months ahead of an accelerated schedule set in December 2024 — real progress, but on a schedule that had already been extended once. As Hush Street’s Gowanus tracker put it: being ahead of a schedule that was already years late is a different claim than being on time.
The OIG’s warning about a possible second round of dredging is the detail worth watching. If further delays force the EPA to redo work in the canal’s upper or middle segments, the 13x cost figure — already the headline number here — is the one most likely to move again.
Why It Matters
Every other project in Gowanus right now — new residential towers, Gowanus Green’s fully affordable megaproject, even the neighborhood’s own Douglass & DeGraw Pool — sits downstream of this cleanup finishing on schedule. A federal infrastructure project running 13 times over budget isn’t an abstract line item; it’s the thing everything else in the neighborhood is quietly waiting on.
What’s Next
Construction of the larger Head End Tank’s base and walls is targeted for completion in late 2026. Neither tank is expected to be operational until 2029, and the EPA’s middle-segment dredging remains underway with no confirmed completion date. For the fuller picture — the towers rising alongside this cleanup, the Carroll Street Bridge’s reopening, and the NYCHA campuses nearby — see Hush Street’s Gowanus Development Tracker.
Sources: EPA Office of Inspector General; Gothamist; City & State New York; NYC DEP; Brooklyn Paper; Gowanus Canal Community Advisory Group.
Hush Street Editorial researches and reports on the projects, permits, and physical changes reshaping Brooklyn — and, more broadly, New York City. Reporting draws on primary-source city records — Department of Buildings filings, land-use and planning applications, agency and community-board documents — verified and cross-checked against independent reporting where it exists. Coverage is continuously updated as new filings and decisions are recorded, and confirmed facts are distinguished from open questions.
