Private Well
A water supply serving a single household — not regulated by the EPA or the Safe Drinking Water Act. About 43 million Americans rely on private wells and are responsible for their own water testing.
How It Works
Private wells are exempt from the Safe Drinking Water Act because they serve fewer than 25 people. This means no federal testing requirements, no enforceable standards, and no monitoring by state or local authorities (though some states have their own well regulations). The EPA and CDC recommend private well owners test annually for coliform bacteria, nitrate, pH, and total dissolved solids. Wells near agricultural areas should also test for pesticides. Wells near industrial areas should test for volatile organic compounds. PFAS testing is recommended for wells near military bases, airports, or areas where firefighting foam was used. Testing costs $20-300 depending on the contaminants tested. Many well owners never test their water, potentially drinking unsafe water without knowing it.
Related Terms
- Groundwater — Water found underground in aquifers — the drinking water source for about half of all Americans and nearly all rural residents, generally cleaner than surface water but vulnerable to contamination from agriculture and industry.
- Nitrate — A contaminant from agricultural runoff and septic systems that is especially dangerous for infants — causing "blue baby syndrome" (methemoglobinemia) at levels above 10 mg/L.
- Safe Drinking Water Act (SDWA) — The primary federal law governing drinking water quality — authorizing the EPA to set standards for contaminants in public water systems and requiring states to enforce those standards.
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About This Definition
This definition is part of the IsWaterSafe Drinking Water Safety Glossary — 22 terms explaining water contaminants, treatment methods, and safety standards. Written for homeowners, renters, journalists, and public health professionals.