They can only be traced through testing because they colorless and odorless, Susca said. Another contaminant is manganese, which is gray and can stain clothing, making it easier to detect, he said
Other contaminants include coliform and E. coli bacteria, often linked to sewage systems, Susca said. Manmade substances, such as gasoline, are also sometimes found in groundwater, he said.
Approximately 250,000 New Hampshire homes — or about 40 percent — rely on wells for water, he said. Rather than take a chance, homeowners should have their wells tested, he said.
DES provides free test bottles and can test the water for approximately $85 a sample, depending on the contaminant. There are also approximately 20 private labs in the state that test drinking water, including Granite State Analytical of Derry.
The solutions and costs for these dealing with these problems can vary, Susca said.
Granite State owner John Lyons said his company conducts about 1,000 tests a month for those interested in making sure their water is safe.
Lyons recommends that anyone with a private well have their water tested. He said the public is becoming increasingly aware of the importance of testing.
For more information about the state’s testing recommendations and a list of accredited labs, go to des.nh.gov and select private well testing from the A to Z list, or call the NHDES Drinking Water and Groundwater Bureau at 271-2513.