- Why was the assessment done?
Under the 1996 Amendments to the federal Safe Drinking Water Act, the NH Department of Environmental Services (DES) is required by the US EPA to assess every source of public drinking water for its relative susceptibility to contaminants regulated by the Act. This assessment is based on the results of the most recent sanitary survey performed at this system and a land use inventory within 500 feet of the well(s). It describes susceptibility based on water quality and wellhead information and the type, density, and location of land uses that could represent a risk to the well(s) if contaminants often associated with these land uses are inappropriately released to the environment. Factors that are ranked "relatively susceptible" generally increase the risk of drinking water contamination.
- How were land uses identified?
Land uses shown on the map from Part 3 are characterized as potential or known contamination sources. Known contamination sources are sites where contaminants are known to have been released onto or into the ground. Potential contamination sources are facilities that typically use large quantities of regulated substances. Many of the land uses are regulated by DES and were already in a DES database and the DES Geographic Information System. Others were identified by driving through the area that surrounds the well(s). Although the most current land use information was used to rank the susceptibility factors in Part 1, it should be noted that the ranking and maps could contain errors and should be reviewed carefully by the user of this information.
- Will the potential contamination sources shown on the attached map contaminate my source?
Potential contamination sources are facilities that typically use, produce, handle, or store contaminants of concern, which, if improperly managed, could find their way to a source of public drinking water. It is important to understand that a release may never occur from a potential contamination source provided it is using good management practices. Many potential contamination sources are regulated at the federal level, the state level, or both to reduce the risk of a release. There are a number of methods that water systems can use to work cooperatively with potential contamination sources. A brochure is available outlining protection options for transient systems.
- What do the "low susceptibility" and "relatively susceptible" rankings mean?
Under the assessments, an in-depth, site-specific investigation of every land use in the protection area was not possible. Instead, DES used its Geographic Information System coupled with a windshield survey and its records of each source of public drinking water to derive the rankings. Each of the nine factors evaluated for the assessment (see Part 1) is ranked "low susceptibility" or "relatively susceptible." Generally, a "low susceptibility" ranking means that a given type of potential contamination source is not present within 500 feet of the well, that the most recent sanitary survey found no ongoing problems with well construction, or that DES's records indicate no current confirmed detections of contaminants that are likely to originate from human activity. Similarly, a "relatively susceptible" ranking means that a given type of known or potential contamination source is present within 500 feet of the well, that the most recent sanitary survey did find ongoing problems with well construction, or that DES's records do indicate current confirmed detections of contaminants. Part 1 also lists the number of factors that were ranked in each of these two categories.
- How should this assessment be used?
This assessment should be used to plan for improved protection of the well(s). DES strongly recommends that action be taken now to ensure that the "low susceptibility" factors remain low and the risk from "relatively susceptible" factors, if any, be minimized to the extent possible. It is important to remember that once contaminated, drinking water sources can be extremely expensive and sometimes technically impossible to clean up. Guidance for protecting this well is contained in a brochure for transient systems. Technical and financial assistance are available from DES to assist in the development and implementation of protection programs.
- If I have questions or want help protect drinking water whom should I contact?