PRIVATE WELLS IN URBAN AREAS 
 
 
 

An increasing number of people in the Boston metropolitan area are installing private wells in areas where public water supply is available.  Some of them are installing wells because of the increase in MWRA water rates; some because they live in towns with summer water restrictions.  But are these wells really safe?  And are they being connected in a way that puts the public supply at risk? 
 

Most private wells are not tested for volatile organic compounds (VOCs), which include many of the most common – and potentially dangerous – groundwater contaminants, such as industrial solvents and gasoline.  The standard well test only includes bacteria and a few inorganic chemicals like nitrate and sodium.  A clean bill of health for the standard test does not mean a well is free of VOCs.  Most of these chemicals are tasteless and odorless in drinking water.  Unless you test your well for VOCs, you won't know whether you have a VOC problem. 
 

VOCs have been found in many private wells in pristine settings in Massachusetts.  In developed and urbanized communities like those that make up the MWRA service area, the chance of having VOCs in the groundwater is much greater.  All private wells in these areas should be tested for VOCs before being used for drinking water. 
 

If a residence is connected to both a private well and public water supply, the piping carrying the private well and public water cannot be connected anywhere.  Otherwise an illegal "cross connection" is created, through which private well water in the building's pipes may be siphoned into the public water mains.  Therefore, residences served by private wells must either be physically disconnected from the public water system, or the pipes carrying private well and public water must be kept completely separate. 
 

If you intend to install a private well, you must contact your local Board of Health.  If you presently receive public water supply, you must also contact your local water supplier. 
 

This fact sheet is designed to give guidance to Boards of Health, public water suppliers, plumbing inspectors and present or potential well owners.

- Prepared by the Massachusetts Department of Environmental Protection, Northeast Regional Office, July 1992.  Contact and reference information updated October 2008.

      Private Wells 
 

Neither the Federal government nor the Commonwealth of Massachusetts has direct jurisdiction over private water supplies.  Under Massachusetts law, local Boards of Health have broad authority to "make reasonable health regulations" and are specifically authorized to require a safe and adequate supply of water for any place of habitation.  Therefore, local Boards of Health have jurisdiction over private wells. 
 

The Massachusetts Department of Environmental Protection (DEP) has published the Private Well Guidelines to assist Boards of Health in regulating private wells.  This publication discusses design, construction, maintenance, testing, contamination sources and closure procedures for private wells; a model Health regulation for private wells is included.  The Private Well Guidelines may be obtained from the State Bookstore in Boston or Springfield. 
 

A simple, but vital, fact about private wells is that they are "private."  The well owner is not subject to water bills or to the requirements placed upon public water suppliers; however, the well owner has the responsibility to maintain the well and ensure that the water is fit to drink. 
 

Public water supplies must be tested for bacteria and many chemicals on a regular basis – and must meet drinking-water standards – under the Federal Safe Drinking Water Act.  State and Federal officials review tests of the public supplies to ensure their fitness to drink.  Beyond the testing required by the local Board of Health, a private well is only tested at the discretion of the owner.  Therefore, a private water supply is not likely to be as thoroughly tested as a public water supply unless the owner of the private supply makes a concerted effort to do so.  
 

If a private well is contaminated by petroleum or a hazardous material, the Department of Environmental Protection will endeavor to find the party (or parties) responsible for the contamination.  However, finding the source of the contamination and cleaning up the water supply can take years.  In the meantime, connection to a public water supply or installation of a home water treatment device may be necessary — at the well owner's expense. 
 

      Overburden and B