Wells are holes in the ground with depths below the water table. The water table is the level of groundwater below the surface. Wells fill up based on groundwater level and the water is then pumped to the surface for usage. There are both private and public wells located throughout Massachusetts with private wells used in many homes.

“Private wells are derived from a “private water supply – (they) provide water for human consumption and consist of a system that has less than 15 service connections and either (1) serves less than 25 individuals or (2) serves an average of 25 or more individuals daily for less than 60 days of the year.” - Mass.gov

PRIVATE WELLS

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Overview

The Town of Stow, Massachusetts, does not have a centralized water delivery system; instead, it completely relies on groundwater supplied from both public and private wells. Due to the need for power to operate, most residences and other private or public sites maintain separate wells of varied depths. The productivity of the aquifer and the depth of the well both affect how vulnerable the home water supply is. At the moment, Stow lacks the infrastructure necessary to replace its water supply from shared sources amid extreme situations like droughts. Wells have been dry recently, forcing residents to use bottled water. Due to their shallow wells, residents of the Lake Boon/Gleasondale area were shown to be the most vulnerable to drought. However, complete information on well depth and type in Stow is lacking.

While droughts are a concern, Stow's wells may potentially be contaminated depending on their depth. There are two different types of wells: dug/bored wells, and drilled wells. Dug/bored wells are holes in the ground dug by shovels or backhoes. Pipes are driven into the ground to create

underground wells. To prevent collapse, they are lined or cased with stones, brick, tile, or other sturdy materials. Dug wells are particularly vulnerable to contamination because they get their water from shallow aquifers, where numerous toxins are concentrated. In contrast, drilled wells go thousands of feet deep and require casing to be installed. They have a lower risk of contamination due to their depth and the use of continuous casing. Drilled wells are a more dependable source of water and are less likely to become contaminated.

How Water Moves 

When you take water from a well, water from the ground slowly starts to fill the well up again. The rate of this refilling has to do with how much groundwater surrounds the well and the porosity of the soil. The smaller the space, the slower the water fills up, or “recharges” the well. In most wells, a pump is placed to suck out the water.

The effluent is piped to a treatment facility after usage, just like with any other water source, before returning to the ecosystem. The main distinction is that treated water from a wastewater treatment facility is not used for drinking purposes; The source of drinking water is distinct from the treatment because the wells are pulling from groundwater.

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Who is Responsible for Maintaining the Infrastructure?

While the EPA protects public drinking water systems, private wells are not covered. Private well owners are responsible for ensuring that their water is free of pollutants. Owners can ensure the safety of their wells by regularly testing and ensuring that the well companies with the local boards of health since they are the primary authority over the regulation of private wells. A Private Well law has been developed, and local boards of health have the authority to enact it. Local boards of health can determine site selection, construction, water quality, and quantity for private wells.

Affects on Water Cycle

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A large portion of rainfall is absorbed by the ground. Rainwater that is not utilized by plants passes through pores and gaps in rock until it reaches a dense layer of rock. Water gets trapped in pores and gaps above dense rock barriers that are below ground. Groundwater is the water used in drilled wells.

The rate at which water is taken from the water table is important because excessive water withdrawal can cause a “cone of depression” in the water table. A cone of depression is a conical depression that can occur if a high flow rate well is installed too close to another well. A high flow rate well’s cone of depression can pull water tables down so far that neighboring wells no longer have water. A well should not over-pump the water table because the water table will drop permanently and cause surface elevation to decrease