Carlisle's Infrastructure:
What's at Risk?
Carlisle is unique because of its abundance of nature, its mix of wooded and agricultural areas,
and its long-standing commitment to preserving historic and natural vistas.
It is also unique in that it primarily relies upon well water and private septic system.
As one of only 9 adjacent small towns that lack both municipal water and sewer, Carlisle, in particular,
is confronted with additional challenges. The majority of our town is bordered by areas that don’t have MWRA piped water. Only Bedford, across the Concord River, and Billerica, which collects water from the Concord River, are exceptions. Additionally, several of the other towns lacking water and sewer are located far from Boston, outside Route 495, and do not share Carlisle's profile as a Boston bedroom community.
The MFCC plan appears to rely on utilizing existing septic, water, and storm water infrastructure,
with the attendant risk that these systems may become over-burdened.
Added to these risks is the increased tax burden and traffic.
Financial Impact
In effect, the MBTA law amounts to a stealth tax. Anytime you impose mandates on a community requiring added compliance and infrastructure costs and other services to be rendered without funding, it’s equivalent to a tax.
Water Supply Impact
Preventing groundwater contamination and ensuring an adequate supply of drinking water should be of paramount importance to the Town. The MFCC plan potentially puts the wells of abutters to the MFCC sites at risk. You can read more about the risks here.
Current Drinking Water Regulations: 310 CMR 22: The Massachusetts Drinking Water Regulations.
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Septic System Impact
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Title 5 of the State Environmental Code, 310 CMR 15.000, is a regulation that protects your home and our community from the impact of sewage disposal. It requires the proper siting, construction, and maintenance of all onsite wastewater disposal systems. Properties that contain both a septic system and a well are considered nitrogen sensitive and are subject to stricter regulations.
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Carlisle’s Development Standards have long recognized the unique challenges we face to accommodating multi-family housing that relies on septic systems. Not only do we
face common state-wide challenges, our geology and sub-surface conditions pose particular and unique risks. -
The Planning Board and Board of Health met on 4/14/2025 to discuss possible use of alternative septic systems and their known risks. The BoH explained they are risky alternative in part because they require qualified operation and reporting.
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Kay's Walk on Bedford Road and Benfield Farms are two examples of high density housing septic system failures.
Traffic Impact
Carlisle’s existing neighborhoods lack infrastructure and suitable roads. Many are served by private roads and/or narrow and scenic roads. Spreading the MBTA Communities development across town on the existing road network will increase traffic and use of
automobiles.
Historic Homes Impact
Any dense development introduces concerns about preserving the pastoral and rural character of Carlisle, which is unique and special in a community so close to Boston. Any attempt to redevelop an existing property will invariably require some demolition to existing building structures and foundations.
You can read more here.
ADU + MBTA Community Zoning = Overdevelopment of Carlisle
In 2024, ADU (accessory dwelling units) policy was signed by the governor. An ADU is a small residential living space located on the same lot as another home. The ADU allows property owners to build an ADU without having to get special or discretionary approval from the local zoning board. ADUs can be internal within an existing primary residence, like converting a basement into an apartment, attached to a primary residence as a new construction addition, or completely detached, like a cottage or converted detached garage in a backyard.
ADUs are not factored into MBTA zoning compliance, which can lead to higher housing density in Carlisle. This, in turn, can exacerbates the existing infrastructure challenges posed by the MBTA zoning requirements.
ADU Zoning Amendments are currently
before the Planning Board.
