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KnowYourWellWater

Sources & References

Last reviewed October 25, 2026

We build on primary public sources. Individual articles cite the specific pages used; the organizations below are our main references.

  • US Environmental Protection Agency (EPA) — drinking water regulations and private well guidance.
  • US Geological Survey (USGS) — groundwater science and water hardness classification.
  • Centers for Disease Control and Prevention (CDC) — private well health and testing guidance.
  • State departments of health and environment — state-specific rules and recommendations.
  • State geological surveys and Cooperative Extension Services — regional hydrogeology and homeowner guidance.

Links to external sources open in a new tab and are provided for reference; we are not responsible for their content and they may change over time.