Norwalk, CT
CyrusOne – Norwalk
CyrusOne · Operating · 6 Norden Place
Connecticut's largest data center, opened in 2013 on the site of a former industrial park. Operated continuously as a Tier III colocation facility since opening; predates the state's recent wave of AI-driven proposals by over a decade.
Estimated water use
Estimate0–800,000 gal/day
The operator has not disclosed a cooling technology, so this range spans every cooling type this site tracks, at the published capacity of 16 MW. The width of this range is exactly the uncertainty a cooling-type disclosure would remove.
By cooling technology
- Fully air-cooled≈ 0 gal/day
- Closed-loop chilled water11,360–29,600 gal/day
- Evaporative cooling towers296,000–800,000 gal/day
16 MW capacity: cyrusone.com
Each scenario uses that technology's own published ratio and source. Scenarios are never averaged — no source supports a number in between.
Derived from published industry ratios; actual use depends on the cooling system chosen, operating conditions, load, and weather.
Lifecycle timeline
ObservedConfirmed events only, each with its source.
~January 2013
Construction completed
CyrusOne opens its Norwalk data center, a Tier III facility offering up to 16 MW of power, which becomes Connecticut's largest data center.
SourceJuly 1, 2015
Ownership change
CyrusOne closed its ~$400M all-cash acquisition of Cervalis, an operator of four Tier 3+ data centers and two work-area-recovery facilities serving the New York metro area (500,000+ sq ft total). The Norwalk, CT facility (now branded NYM5) was part of the acquired Cervalis portfolio.
Source
Observed hydrologic data
ObservedFrom nearby USGS and NOAA monitoring stations, refreshed monthly. Dashed lines mark lifecycle milestones.
Groundwater level (ft below surface)
2 stations, overlaid
Regulatory records
ObservedWater permits and environmental compliance records from CT DEEP Water Diversion Program and EPA ECHO.
No permit or compliance record from these sources currently matches this facility.
Other water permits in Norwalk: local context only
29 other diversion permits on file in Norwalk, held by other water users nearby (public water systems, industry, golf courses). The largest:
- NRG Norwalk Harbor Operations, Inc.288 MGD max
- First Taxing District Water Department2.06 MGD max
- First Taxing District Water Department1.9 MGD max
- Norwalk Second Tax District1.87 MGD max
- First Taxing District Water Department1.43 MGD max
Drawdown story
AssessmentIs the water table's behavior near this facility consistent with its estimated draw — and how strong is the evidence? A fixed rubric, recomputed monthly; every number below is stored with the inputs that produced it. Method: attribution-v1.
1 · Pathway
The operator has not disclosed where this facility's water comes from. Until a source is published, the assessment is capped: an unclassified pathway can never raise the score.
2 · Detectability
Even at the high end of the estimate, the draw would be invisible (under 0.2 ft) at the nearest monitored well 6.9 mi away — "not detectable" is the expected outcome.
3 · Signal
No monitored well within 2 miles of this facility — there is no near-field record to compare against controls.
The monitoring record around this facility is too sparse to assess.
Attribution evidence score: withheld · as of 2026-07-22 · attribution-v1