When federal officials moved this winter to buy an empty warehouse at 50 Robert Milligan Parkway in Merrimack, NH, to turn it into an immigration detention center, local resistance quickly focused on the infrastructure.
City officials argued that the city’s water and wastewater systems were not designed for sudden, high-density institutional occupancy on infrastructure that was already operating near peak conditions.
The Merrimack Village District’s maximum daily water production is 3.8 million gallons per day, according to confirmation from the NH Department of Environmental Services. A previous health survey reported average peak month demand of 3.7 mgd, indicating that the system has been operating near its production ceiling during periods of high demand.
On the wastewater side, the Merrimack WWTP has a design capacity of 4.8 mgd under its NPDES permit. A 2024 permit modification reports a recent peak daily flow of 4.1 mgd. This leaves approximately 0.7 mgd of peak day margin between the observed flow and the allowable design capacity of the plant.
Utility engineers size systems for peak daily conditions and wet weather events, not just annual averages. Expansion planning often begins long before a facility reaches its allowable ceiling.
In Colorado, for example, the state health department requires wastewater utilities to begin planning for expansion once sustained flows reach about 80 percent of design capacity and start construction at about 95 percent, according to the state policy review by engineering firm Stantec, which illustrates how capital programs are typically triggered by sustained proximity to design limits rather than violations of permissions
Although DHS eventually pulled out of the Merrimack site after significant community resistance and talks with state officials, infrastructure concerns raised there are now emerging in other communities where the agency has pursued warehouse acquisitions as part of a broader detention expansion effort.
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Proposed ICE warehouse conversion in Merrimack, NH adds to early construction uncertainty
From the local dispute to the national pattern
Across the country, coverage of these disputes reflects a recurring theme: Local governments say they often don’t have enough information to fully assess impacts on sewer, water and other utilities before federal plans move forward.
“Communities fighting ICE detention center conversions say they don’t have the time or tools to fully assess impacts on local services such as sewer, water and emergency infrastructure,” Stateline reported in a national review of the disputes, adding that the federal siting effort has raised “questions about how federal facilities fit into local planning frameworks.”
National reports have documented that federal officials have explored or pursued warehouse acquisitions in several states as part of efforts to expand detention bed capacity, often targeting large industrial buildings not originally designed for residential-scale occupancy. This approach can compress the timeline for reviewing local utilities, especially when municipal infrastructure planning typically takes place over multi-year capital improvement cycles rather than rapid conversion programs.
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Small system scale and proportional impact
In Social Circle, Georgia, local officials publicly cited sewer and water limitations in response to a proposed detention center tied to a warehouse acquisition. The city’s Little River Wastewater Treatment Plant has an allowable design capacity of 0.90 mgd, according to its draft NPDES permit package. As for drinking water, the city’s annual water quality report states that the treatment plant “can produce one million gallons per day.”
These numbers put Social Circle’s municipal systems below 1 mgd in both water and wastewater, a scale that increases proportional impacts.
For context, in Maryland litigation over a proposed 1,500-bed detention conversion near Williamsport, the state alleges that the facility would generate approximately 90,000 gallons per day of wastewater, compared to about 24,768 gallons per day under warehouse use assumptions.
In a 0.90 mgd wastewater plant, an increase of 0.09 mgd would represent approximately 10% of the total design capacity.
Whether the Social Circle system could absorb this increase would depend on its existing average and maximum flows. But the arithmetic illustrates how institutional-scale employment can consume significant portions of available hydraulic margin in small municipal systems.
When pick-up lines, not plants, become the constraint
In Washington County, Maryland, the debate has focused less on treatment plant capacity and more on collection infrastructure.
The state’s complaint challenging DHS’s purchase of an 825,620-square-foot warehouse to convert into a 1,500-bed detention center alleges the property is serviced by a 6-in. side connection to an 8-in. sewer and that these lines may be insufficient to support the increased load. The complaint provides for wastewater generation of approximately 90,000 gallons per day for detention use.
At the plant level, Washington County’s Conococheague Wastewater Treatment Plant, which serves the Williamsport area, has a design capacity of 4.1 mgd, according to the county’s water and sewer plan. Historical average daily flows have been well below this ceiling. In this case, state officials argue that localized pipeline hydraulics, not plant-level treatment limits, could become the bottleneck.
National reports have highlighted how quickly the warehouse-to-detention strategy has progressed. The Washington Post reported that federal officials have explored or pursued acquisitions of warehouses in several states, often with limited public disclosure of operational details or infrastructure demands before local leaders are asked to respond.
In all three cases, infrastructure friction manifests itself differently.
In the Merrimack, the issue is peak-day production margin in a medium-sized system that has historically operated near its peak water production during summer demand.
At Social Circle, the challenge is absolute scale: a 0.90 mgd wastewater plant and a 1.0 mgd water plant facing potential institutional-scale loading.
In Washington County, the focus is on downstream collection capacity (diameter of laterals and main), even when a regional plant has treatment space.
Usability snapshot: ICE Warehouse conversion proposals
| community | Proposed facility scale | Water system capacity | Wastewater design capacity | Reported flow/load | Key constraint problem |
|---|---|---|---|---|---|
| Merrimack, NH | ICE warehouse conversion (beds not formally presented) | Maximum daily production of 3.8 MGD; Peak month average demand of 3.7 MGD | 4.8 MGD | Recent peak daily flow of 4.1 MGD | Peak day water margin; Maximum height of waste water approx. 0.7 MGD |
| Social Circle, Ga. | Conversion of Arrest Discussed Locally | Water plant capacity of 1.0 MGD | 0.90 MGD | Approx. Incremental load of 0.09 MGD (reference 90,000 gpd) | Small scale of the absolute system; proportional impact of demand |
| Washington County, Maryland (Williamsport) | 1,500-bed detention center (by complaint) | Regional system (no central litigation) | 4.1 MGD (Conococheague WWTP) | Expected detention flow of 90,000 gpd vs. 24,768 gpd of warehouse reference | Pickup System Restriction (6″ Side to 8″ Main) |
Sources: NH Department of Environmental Services sanitary survey and NPDES permits; Merrimack WWTP Permit Amendment (2024); Draft Georgia EPD Permit Package for Little River WPCP (GA0026107); Report on the Water Quality of the Social Circle 2024; suit Maryland v. Noem; Washington County Water and Sewer Plan.
The common denominator is typology. Modern logistics warehouses are designed for low-occupancy industrial use, with plumbing and domestic water demand assumptions well below those of residential or institutional facilities. Converting these structures into 24-hour detention centers turns them into a fundamentally different class of hydraulic demand.
Hospitals, prisons and large residential developments often undergo detailed utility impact reviews and phased capacity allocations prior to construction. Warehouse conversions executed under federal authority can compress those timelines, limiting local review and raising concerns about how incremental demand will be absorbed.
Even when individual projects stall, as in Merrimack, the underlying engineering question persists: How much additional institutional load can municipal water and wastewater systems withstand before design margins, peak-day thresholds, or collection limitations require upgrades?
For utilities measured in tenths of a million gallons per day, or for systems already operating near seasonal peaks, this question is not abstract, it is arithmetic.
