Frequently Asked Questions

When selecting a laboratory for water testing, be sure to select a laboratory that is certified by the Massachusetts Department of Environmental Protection (MassDEP).  You can request price quotes from several laboratories, but it is recommended that you take into consideration other factors beyond cost, including laboratory detection limits, ability to use US EPA approved methods, and range of testing offered.

You can read more about water testing on MassDEP’s website and review the list of MassDEP-certified labs.

Private well owners are generally not required to test their water quality, but MassDEP strongly urges private well owners to get their well tested as least once a year.  The Centers for Disease Control and Prevention also recommends testing if there are known problems with well water in your area, you have experienced problems near your well (flooding, land disturbances, nearby waste disposal sites, etc.), you replace or repair any part of your well system, or if you notice a change in water quality (taste, color, or odor).

The University of Rhode Island Water Quality Program has created a testing schedule that outlines what compounds to test for and how frequently you should test them.

Regular testing will allow you to monitor your well over time. Look for trends, and be aware of increasing contaminant levels.

Most contaminants fall under one of two categories: primary and secondary contaminants. Primary contaminants are ones for which EPA has identified a health risk from excessive exposure and has set a maximum contaminant level (MCL) or action level (AL). Secondary contaminants are contaminants that have an aesthetic effect, such as taste, odor, and color. These contaminants are not typically regarded as a health risk.

It is also common to test for Water Quality Indicators (WQI), which include measurements that help to assess the acidity and amount of germs/bacteria in water. Examples of WQIs include total coliform, fecal coliform, and pH.

Many labs offer standard packages for private well owners. These packages include a mixture of common primary and secondary contaminants as well as WQIs. If you have young children, you should be aware of which contaminants might have a greater negative effect on them, such as lead and nitrate.

If a chemical was “not detected” (also reported “ND” or “<” followed by a number), then the amount of the chemical in your water was below the lowest level that the laboratory can reliably measure. Each laboratory has its own detection limits. Being below the detection limit can either mean that the chemical is not present in your water sample, or that it is present at a low level that the laboratory could not detect.

For each contaminant, we include tips on reducing exposure, including some well treatment options. Our “Water treatment” page includes information on common well water treatment systems and which compounds they are effective at removing.

If you decide to treat your water, there are several things you should keep in mind.

• What chemicals you want to remove: Different treatment systems remove different chemicals, and it may not be necessary to lower levels of all chemicals in you water. Deciding what the goal of the treatment system is will help you select the appropriate system.
• Whole-house or point-of-use system: A whole-house system treats all household water for drinking, cooking, showers, clothes washing, etc. Point-of-use systems are smaller and treat only the water that comes through the tap where the treatment system is installed. For example, they can be installed on a kitchen tap and used for drinking or cooking. Depending on the chemicals you are concerned about, you may not need to filter all the water in your home. A whole-house system will not eliminate chemicals associated with the plumbing inside your home because the water is filtered at the point of entry before it is distributed throughout your home.
• Cost: Consider additional costs beyond just the treatment system itself, including installation and maintenance.
• Effort to maintain: Think through any part replacement that may need to occur, who will do the maintenance, and any possible need to “flush” the system, which could have an impact on septic systems.

More information on specific water contaminants:

• University of Massachusetts (UMass) Amherst Center for Agriculture, Food and the Environment, Well Water Fact Sheets
• University of Rhode Island (URI) Water Quality Program, Safe Well Water Tip Sheets

More information about water testing:

• US Centers for Disease Control and Prevention (CDC), Well Testing
• Massachusetts Department of Environmental Protection (MassDEP), Private Drinking Water Testing and the use of MassDEP Certified Laboratories

More information about home water treatment:

• UMass Amherst Center for Agriculture, Food and the Environment, Questions to Ask When Purchasing Home Water Treatment Equipment
• URI/Rhode Island Department of Health, Need to treat your well water? Learn and ask about choices
• CDC, A Guide to Drinking Water Treatment Technologies for Household Use

PFAS (per- and polyfluoroalkyl substances) are a class of chemicals that are added to a wide variety of consumer products to make them non-stick, waterproof, and stain-resistant. PFAS chemicals have been found in public water supplies and private wells across the U.S., including in some Massachusetts towns. Massachusetts Department of Environmental Protection has proposed a standard of 20 parts per trillion (ppt or ng/L) for the total amount of 6 PFAS chemicals (PFOA, PFOS, PFNA, PFHpA, PFDA, and PFHxS) in public water supplies.

For more information on PFAS in drinking water, please visit the PFAS Exchange, our online resource center about PFAS contaminants in drinking water at PFAS-Exchange.org.