Family Owned & Operated Since 1980
Published May 6, 2026
Vermont has roughly 80,000 private wells, and unlike municipal water systems, they are not subject to routine government testing or treatment requirements. That responsibility falls to the homeowner. This guide walks through the most important contaminants to test for, how often testing makes sense, and what your testing options are.
Groundwater picks up minerals, metals, and gases as it moves through Vermont's rock formations - and in certain areas, agricultural runoff, industrial contaminants, and naturally occurring radioactive compounds. The specific risks depend on where you live, the depth and construction of your well, land use in your area, and the local geology.
You cannot tell from the appearance, smell, or taste of your water whether it is safe. Many of the most concerning contaminants - arsenic, nitrates, uranium, PFAS - are colorless, odorless, and tasteless at the concentrations typically found in well water. Testing is the only way to know.
The following contaminants are the most relevant for Vermont private well owners, based on the state's geology, land use history, and confirmed contamination patterns.
Bacterial contamination is the most immediate health risk from a private well. Total coliform bacteria serve as an indicator of whether surface water or animal waste has entered the well; E. coli specifically indicates fecal contamination. Both can cause acute gastrointestinal illness. Vermont's Agency of Natural Resources recommends testing for bacteria at least once a year and after any event that could affect the well - flooding, heavy rain, nearby construction, well repairs, or power outages.
Nitrates enter groundwater from fertilizer application, septic systems, and animal waste. They are a particular concern for infants under six months old, in whom high nitrate levels can interfere with the blood's ability to carry oxygen (a condition called methemoglobinemia). Vermont's agricultural landscape and the prevalence of older on-site septic systems make nitrate testing important, especially for shallow dug wells or properties near active farm fields.
Hard water is the most common water quality issue in Vermont. Dissolved calcium and magnesium leave scale deposits on fixtures and inside pipes and appliances, reduce soap effectiveness, and shorten the lifespan of water heaters and other equipment. Testing hardness helps determine whether a water softener is warranted and, if so, what size and type of system is appropriate.
Iron is abundant in Vermont's bedrock, and many private wells have elevated iron levels. Even relatively low concentrations cause rust-colored stains on sinks, tubs, toilets, and laundry. Manganese, which often occurs alongside iron, causes black or brown staining and has been associated with neurological effects at elevated concentrations. Testing for both iron and manganese is important for well water households.
Water with a low pH (acidic) is corrosive to copper plumbing, brass fittings, and solder joints. In older homes with copper pipes, acidic water can leach enough copper to create both a health concern and a blue-green staining problem on fixtures. Vermont's granite and other crystalline bedrock areas tend to produce more acidic groundwater than limestone regions.
TDS is a broad measure of inorganic materials dissolved in water. A high TDS reading can indicate the presence of minerals, salts, or other dissolved substances and is useful as a screening parameter. It does not identify specific contaminants but flags water that warrants closer investigation.
Arsenic occurs naturally in Vermont's bedrock, particularly in areas underlain by metamorphic and igneous rock. Long-term exposure to arsenic at elevated levels is associated with increased risk of bladder, lung, and skin cancers, as well as cardiovascular and neurological effects. The EPA's maximum contaminant level for arsenic is 10 parts per billion (ppb), but health research suggests that risks exist at lower levels as well. Vermont has documented arsenic exceedances in private wells across multiple counties. This is a laboratory test - it cannot be done in a basic in-home screening.
Uranium is another naturally occurring contaminant in Vermont groundwater, particularly in areas with granite bedrock. It poses kidney toxicity risks at elevated concentrations. Vermont has some of the highest naturally occurring uranium levels in groundwater in New England. If your well is in a granitic area, uranium testing is worth including in a comprehensive panel.
Radon dissolved in well water can be released into indoor air when water is used for showering, dishwashing, or cooking. Vermont has high background radon levels due to its geology, and radon in well water is a documented concern, particularly in granitic regions. Radon testing of well water is separate from air radon testing.
Per- and polyfluoroalkyl substances have been detected in private wells in Vermont, particularly in areas near industrial sites, airports, military installations, and farms that received biosolids. Vermont's MCL for a combined group of five PFAS compounds is 20 parts per trillion for public water systems; private wells have no regulatory requirement but the same health risks apply. PFAS testing requires a certified laboratory - it is not included in standard in-home water tests.
At minimum, Vermont's Agency of Natural Resources recommends testing well water annually for bacteria and nitrates. A comprehensive baseline test covering all major parameters - including hardness, iron, manganese, pH, arsenic, and uranium - is recommended when you first move into a home with a private well and then periodically thereafter (every three to five years is a common guideline, or more frequently if land use near the well changes).
Test promptly after any of the following: flooding near the well, a nearby spill or chemical application, a change in the water's appearance, taste, or odor, after well maintenance or repairs, or if a neighbor's well test returns unexpected results.
Clear Water Filtration offers a free in-home water test that covers the most common water quality parameters: hardness, iron, manganese, pH, total dissolved solids, and chlorine. This test is done on-site by one of our water quality specialists and gives you immediate results for the issues most likely to affect day-to-day water quality and home systems.
What the free in-home test does not cover: bacteria, nitrates, arsenic, uranium, radon, or PFAS. Those contaminants require laboratory analysis with specialized instrumentation and proper sample handling. For comprehensive well water testing - especially if you are buying a home, have not tested in several years, or have reason to suspect contamination - we refer customers to our certified-lab partner for a full panel.
The two tests complement each other, and many customers benefit from both. Learn more about free water testing services in Vermont from Clear Water Filtration.
We test for hardness, iron, manganese, pH, TDS, and chlorine at no charge. Call 802-496-5544 or schedule online.
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