A water test for well water should start with a core lab panel: coliform bacteria, nitrate, hardness, iron, manganese, pH and total dissolved solids. Add situational tests, arsenic, lead, PFAS, radon, based on your region and plumbing, and repeat the bacteria and nitrate checks yearly. Because nobody monitors a private well but its owner, this test is the single most important purchase in well ownership.
Why testing is entirely on you
Private wells are not federally regulated under the Safe Drinking Water Act, so no utility, city or agency tests the water your family drinks. The EPA reports that around 15 percent of the US population, over 43 million people, rely on private wells, and that a USGS study of 2,100 private wells found about one in five carried at least one contaminant above a human-health benchmark. The contaminants that matter most, bacteria, nitrate, arsenic, have no taste, smell or color, which is why clear, good-tasting well water can still fail a lab panel. Testing is the only way to know.
The core panel and the situational add-ons
The core panel covers the findings that drive both health decisions and equipment choices: coliform bacteria as the indicator of contamination pathways, nitrate as the signal of surface or agricultural influence, and hardness, iron, manganese, pH and total dissolved solids as the numbers that size and select treatment equipment. Add-ons depend on context: arsenic and radon where local geology warrants, lead where household plumbing is older, PFAS near suspected sources, and volatile organics near fuel or industrial sites. Your state health department or extension service can tell you which add-ons your county's geology justifies.
Home kit or certified lab
Home test strips are useful for the parameters that guide equipment, hardness, pH, iron, and for quick recheck between proper tests, but they are screening tools with coarse readings. Anything with health stakes, bacteria, nitrate, arsenic, lead, belongs at a state-certified laboratory, where detection limits, chain of custody and quality control are real. Most certified labs mail sampling bottles with instructions; follow them exactly, because a bacteria sample taken sloppily contaminates itself and buys you a false alarm. If you want the sampling handled professionally, our page on finding well water testing near you covers local services that collect and submit for you.
When to test and retest
The standard rhythm is bacteria and nitrate every year, the fuller panel every few years, and an immediate retest after specific events: flooding, work on the well or pump, a new septic system nearby, a change in taste, smell or color, or unexplained stomach illness in the household. Wells change over time with drought, water table shifts and land use around them, so a clean result years ago is history, not status. Keep the reports; a file of results over the years turns any future problem into a before-and-after comparison instead of a mystery.
Questions people ask about water test for well water
What should a basic well water test include?
Coliform bacteria, nitrate, hardness, iron, manganese, pH and total dissolved solids form the core panel. Bacteria and nitrate carry the health stakes; the rest select and size treatment equipment. Regional add-ons like arsenic or radon depend on local geology.
How often should well water be tested?
Bacteria and nitrate annually, the broader panel every few years, and an immediate test after flooding, well or pump work, nearby septic changes, or any shift in taste, odor or color. Wells change with conditions, so old results do not certify current water.
Are home well water test kits accurate enough?
For screening hardness, pH and iron, yes, and they are handy between lab tests. For bacteria, nitrate, arsenic or lead, use a state-certified laboratory: the health consequences of a wrong answer are too large for strip-grade precision and uncontrolled sampling.