Drinking Water Contamination in Charlton: Education and Solutions Executive Summary


Clean drinking water is an essential resource for human survival. Humans depend on clean water for consumption, cleaning, and sanitation. Between the 1980s and 1990s two Exxon gas leaks contaminated the groundwater in the Town of Charlton, Massachusetts with the gasoline additive methyl tertiary butyl ether (MtBE). Another chemical, 1,4-Dioxane, has been found in Charlton residents’ wells near the Charlton-Southbridge border, where the Southbridge landfill is located. Contaminants like MtBE and 1,4-Dioxane are introduced into the environment while other contaminants, like arsenic, are naturally occurring. A large arsenic vein runs through Charlton, like many other communities in New England (Romero et al. 2008).

Many residents in Charlton rely on private wells for their drinking water, leaving them potentially subject to the contamination. Residents living in affected areas have received bottled water, municipal water from the neighboring Town of Southbridge, or have installed point of entry treatment (POET) systems on their private wells. There are sufficient POET systems for both arsenic and MtBE, but there are no proven well treatment systems for 1,4-Dioxane.

Public water systems must comply with drinking water regulations to provide water to homes. The most important drinking water law is the federal Safe Drinking Water Act (SDWA). The SDWA mandates water has clean taste, smell, and appearance while meeting the required maximum contaminant levels (United States, 2004). The SDWA grants the United States Environmental Protection Agency authority to regulate water systems in the United States.

Charlton officials are concerned for residents’ safety because many Charlton residents who live in areas affected by contamination have private wells. Robin Craver, Charlton’s Town Administrator, and James Philbrook, Charlton’s Health Director, sought assistance from Worcester Polytechnic Institute’s (WPI) Massachusetts Water Resource Outreach Center (WROC) to inform residents about public water lines, well water testing, and POET systems.


Our goal was to inform Charlton residents of Charlton’s groundwater contamination, the importance of independent water testing, the benefits of connecting to town water, and approaches for Charlton residents to decontaminate their private wells. To accomplish this goal, we developed five objectives:

  1. Assess Charlton’s drinking water sources, methods of well testing, and treatment.
  2. Gauge public awareness of Charlton’s drinking water contamination.
  3. Research strategies to identify and mitigate contamination in private wells.
  4. Develop a list of recommendations for Charlton residents and officials.
  5. Produce two informational videos for Charlton residents.

To accomplish these objectives, we scheduled in-person interviews with experts, and state and town officials. We conducted an online and in-person survey with Charlton residents to gauge public awareness of the contamination in Charlton, to learn where residents get their water, and to see if they are willing to connect to public water. We researched POET systems to evaluate their effectiveness at mitigating the contamination in Charlton’s drinking water. This led to a list of recommendations for Charlton residents to follow, as well as recommendations for future projects. Finally, we produced informational videos identifying the implications of drinking water contamination, how to conduct well water testing, and the benefits of public versus private water supplies.


Throughout our research we discovered potential solutions for Charlton residents, as well as shortcomings in current law, resident knowledge, and science. We grouped our 8 primary findings into three subcategories to portray our findings as we understand them: issues the town faces, Charlton residents’ awareness, and potential solutions for Charlton residents. We believe by researching and discovering issues, solutions, and public awareness, we will help inform officials of ways they may aid residents.

During our research we discovered issues we did not foresee. For example, although some means of removing 1,4-Dioxane exist, there is no proven method for treating the chemical to achieve safe levels. Carbon bed filters remove 1,4-Dioxane, but experts in water treatment are not sure how the filters are working, and they are concerned because the carbon filters barely remove enough 1,4-Dioxane to meet standards, which are subject to change (Gary Magnuson, Mark Baldi, personal communication, 2017). Another issue we found is there is competing information regarding drinking water safety in Charlton. Residents are concerned 1,4-Dioxane is not taken as seriously by experts as known carcinogens, while experts are concerned arsenic is overlooked by many residents. Additionally, some Charlton residents have a misperception about the quality of public water. Residents are hesitant to connect to public water imported from neighboring Southbridge, believing the water to be dirty city water. Local experts argue the water from Southbridge is pristine, and a tour of the Southbridge treatment facility highlighted the multitude of processes the water goes through for treatment. One of the biggest dilemmas Charlton faces is property and contamination clean-up laws need stricter standards and enforcement. In Charlton, home sellers are not required to test for contamination or prove their private wells are safe, so many residents may assume they are buying a safe water supply (James Philbrook, personal communication, 2017). Experts are also worried contaminant levels for 1,4-Dioxane and MtBE are set too high, arguing these levels should be lowered (Gary Magnuson, personal communication, 2017). On top of high allowable contaminant levels, these levels are only guidelines meaning the Massachusetts Department of Environmental Protection (MassDEP) may or may not act depending on the severity of the contamination (Marielle Stone, Mark Baldi, personal communication, 2017). Another concern regarding laws and enforcement is when contamination occurs: contaminators need only clean their sites, not external sites where contamination has spread (Robin Craver, personal communication, 2017).

We found a gap in residents’ knowledge of Charlton’s contamination, but also ways to inform residents. From our survey we found at least one in four Charlton residents are unaware of local contamination. Moreover, a majority of residents surveyed live by contaminated areas, but only 29% of residents surveyed believe they have been affected by water contamination. Additionally, over a quarter of residents never heard of MtBE, and a third of residents have never heard of 1,4-Dioxane. The survey results confirmed the need to combat this resident knowledge gap.  We discovered multiple methods for informing residents. When we conducted our survey in-person we provided brochures including details about MtBE and 1,4-Dioxane, as well as Charlton’s Board of Health contact information in case residents wanted to learn more. For the online format of the survey, we included links to pdf files with information on MtBE and 1,4-Dioxane. We also went on Richard “Dick” Vaughan’s talk show on Charlton Community Television Channel 12 because town officials and residents stated many residents watch his show.

Although we discovered issues related to Charlton’s groundwater contamination, we also found some solutions for residents. After receiving input from experts and officials, we found certified labs are the most reliable means of testing drinking water. Do-it-yourself kits are cheaper and more convenient, but typically do not test for MtBE and 1,4-Dioxane. Labs can test for every contaminant found in Charlton, often providing recommendations for specific filters and further steps for residents (Mark Baldi, personal communication, 2017). We also found public drinking water is more advantageous for Charlton residents than private wells. Residents who connect to public water would not have to pay betterment fees or connection fees if they connected to the new waterline within one year of the beginning of its operation (James Philbrook, personal communication, 2017). Residents connected to public water would only pay a quarterly fee for clean water monitored and treated by professionals, while residents with private wells have to pay for annual testing, and maintenance which may not guarantee the level of quality public water systems provide (Chris McClure, personal communication, 2017). Because public water is not available to all residents, we researched private well treatment and found point of entry treatment (POET) systems are the most effective treatment option available for residents with private wells who cannot connect to public water. Available POET systems meet Charlton’s needs, removing MtBE, arsenic, and 1,4-Dioxane to a degree. While POET systems are less effective at treating water than public water systems, POET systems are still more effective at removing contaminants than simple filters residents may put on their taps (Gary Magnuson, personal communication, 2017).


We developed recommendations specifically for Charlton officials and residents to inform residents of the steps they should take to secure clean drinking water. For Charlton officials, we recommend playing the videos we produced on local television stations, radio stations, websites, social media pages, and in schools. The videos we produced contain information regarding Charlton’s groundwater contamination, and ways residents may ensure clean water supplies. For residents with private wells we recommend testing well water annually through professional labs certified for the contaminants present in Charlton’s groundwater. Certified labs conduct thorough testing while do-it-yourself testing kits usually do not test for MtBE and 1,4-Dioxane. For residents living along new and proposed water lines we recommend connecting to public water. Some water lines are shown in Figure 1 on the following page. Connecting to public water would be cheaper for residents and a better investment, as betterment and connection fees are waived, residents’ property values increase, they have a clean water supply, and quarterly fees are cheaper than paying for well testing and maintenance. For residents who do not have the option of connecting to public water we recommend installing POET systems. POET systems are able to remove the contaminants present in Charlton’s groundwater such as MtBE, arsenic, and 1,4-Dioxane. These systems are relatively expensive costing upwards of $1000 to install, but they help protect residents from contamination more effectively than typical water filters.


 Figure 1: Existing & Proposed Water Lines Charlton, MA (ExxonMobil, 2016)

We also developed recommendations for future projects and research to help the Town of Charlton. We recommend a future project aimed at reducing the cost of well water testing. Town officials could survey residents to get an idea of the price residents are willing to pay for testing, and interview various labs to find price ranges for testing different contaminants. Officials would try to negotiate a lowered price with local companies to help more Charlton residents test their wells. We recommend a future project dealing with various methods of municipal groundwater decontamination. Researchers could focus on areas where bedrock hinders contamination removal, applying what they learn to Charlton. Tests could be run in various softwares to analyze the best methods of decontamination for Charlton. We recommend a future project analyzing existing POET systems. Researchers could gather information from various suppliers to compare cost, efficiency, energy consumption, contaminants removed, and other criterion to determine the best POET systems for Charlton residents. Finally, we recommend the Town of Charlton collaborate with WPI to develop a project dealing with 1,4-Dioxane filtration. Students could analyze carbon filters to understand how they work at removing 1,4-Dioxane, focusing on any chemical reactions taking place, analyzing system efficiency, and using what they learn to create a new system more effective at removing 1,4-Dioxane.


Overall, we believe our project achieved all of our goals and objectives. All of our findings are supported by both our background research and field research we conducted. Our educational component may help to inform any interested Charlton residents of the implications of the groundwater contamination in Charlton and steps they can follow to ensure clean drinking water in their homes. However, to ensure clean drinking water for all residents, more work must be done for the Town of Charlton.