Pennsylvania has one of the highest rates of private well reliance in the country — roughly a third of the state’s population depends on a private well or spring. Pennsylvania is also one of the few states with no statewide well-construction standard, which means well quality and construction practices can vary significantly by county and by driller. As with every state, private wells are not regulated under the federal Safe Drinking Water Act, and testing is the well owner’s responsibility.
Why test
Bacteria, in particular, is a common finding in Pennsylvania wells — many are shallow or drilled into fractured bedrock, which can allow surface water (and the bacteria it carries) to reach the water table more easily than in areas with thick, uniform soil cover. None of the common contaminants below have a reliable taste or odor warning sign at concerning levels.
What to test for
A baseline panel for a Pennsylvania well should include:
- Total coliform bacteria and E. coli — a standard, foundational test given how common bacterial results are in Pennsylvania’s well population.
- Nitrate — relevant in agricultural areas and near septic systems, and especially important if the household prepares infant formula with well water.
- Arsenic — naturally occurring arsenic has been documented in some Pennsylvania groundwater, though less uniformly than bacteria.
- Lead — relevant mainly to household plumbing.
- Radon and gross alpha (radionuclides) — parts of Pennsylvania, particularly areas with granite or certain bedrock geology (such as the Reading Prong region), have documented naturally elevated radon and other radionuclides in groundwater; a lab or extension office serving your specific county can advise whether this applies to your area.
How often to test
Pennsylvania DEP recommends annual testing for bacteria at minimum, with EPA’s general guidance of annual bacteria and nitrate testing applying statewide; retest any time water quality changes noticeably, after well or plumbing work, or after flooding.
Where to find a certified lab
Pennsylvania DEP’s water-testing guidance (see the source link above) provides direct links to the state’s lists of certified laboratories for chemical contaminant testing and for bacteriological testing, plus contact information for DEP’s six regional offices.
After you test
If a result comes back above a health-based guideline, see our filter guides for which technologies are certified to address that specific contaminant.