Radon and PFAS Due Diligence for New York Sellers
Overview
Radon and PFAS require different, property-specific due diligence. Radon is a naturally occurring radioactive gas that can enter buildings; New York State Department of Health (NYSDOH) recommends fixing a home when radon test results are 4 picocuries per liter of air (pCi/L) or higher. PFAS are a group of human-made chemicals that may be found in drinking water, including some private wells.
For a private well, New York does not regulate PFAS in private wells. NYSDOH uses the state's public-water standards for PFOA and PFOS - 10 parts per trillion (ppt), each - as guidance when evaluating private-well results and recommending actions to reduce exposure. Do not describe those public-water standards as a private-well legal limit.
This article provides general educational information only. It is not legal, environmental, health, lending, disclosure, or professional advice. Testing, risk, treatment, and disclosure decisions are property- and jurisdiction-specific. Consult the relevant agency and qualified professionals for the property involved.
Key Strategy
Use current, property-specific data. Do not infer an indoor radon result from a county or regional label. NYSDOH says radon testing is optional in New York and advises testing when buying a home; its public county data do not represent every home. If a seller elects to test, retain the report, the test conditions, and the laboratory information.
For a private well, start with the local health department. NYSDOH directs owners concerned about PFAS contamination to their local health department or its Bureau of Environmental Exposure Investigation for local contamination information, testing advice, result interpretation, and exposure-reduction options. Use an appropriate laboratory and follow its collection instructions.
Describe the result precisely. State the date, location, test method, laboratory, analyte, and reported result. Do not promise future regulatory compliance, a treatment outcome, a resale effect, or a remediation cost. If treatment is being considered, have a qualified professional evaluate the result and the property's water system.
What To Do
- Review the seller's existing radon and private-well records, including dates, laboratory reports, treatment records, and post-treatment testing.
- If a radon test is obtained, follow the testing instructions and use a laboratory approved through New York's Environmental Laboratory Approval Program when the result will be relied on in a transaction.
- If radon is at or above 4 pCi/L, NYSDOH recommends fixing the home. Obtain qualified, property-specific advice on mitigation and test after any mitigation work to confirm its performance.
- If a private-well PFAS concern exists, contact the local health department or NYSDOH before choosing a testing or treatment response. NYSDOH notes that granular activated carbon and reverse-osmosis filtration can reduce PFAS in drinking water, but selection and performance are property-specific.
- Share accurate, complete existing reports with the appropriate transaction professionals. Do not substitute a generic risk statement for a current test report.
Common Mistakes
- Treating a regional radon pattern as a test result for a particular home.
- Calling 10 ppt a legally enforceable private-well PFAS limit; NYSDOH uses the public-water standards as guidance for private wells.
- Selecting treatment, stating a treatment result, or quoting a remediation cost without a property-specific evaluation.
- Omitting the test date, laboratory, analyte, or sampling context when describing an environmental result.
Frequently Asked Questions
What radon level does New York recommend addressing?
NYSDOH recommends fixing a home when radon test results are 4 pCi/L or higher, and says owners may also consider fixing results between 2 and 4 pCi/L. The recommendation applies to the tested home; a regional description is not a substitute for testing.
Should I test radon before selling?
NYSDOH recommends testing when buying a home and says radon testing is optional in New York. Whether a seller tests before listing is a transaction decision; if testing is used, preserve the report and avoid broader representations than the report supports.
What are New York's PFAS numbers for a private well?
New York's public-water standards for PFOA and PFOS are 10 ppt each. NYSDOH uses those values as guidance for evaluating private-well data, because private wells are not regulated for PFAS by the state.
What should I do if a private-well PFAS result is concerning?
Contact the local health department or NYSDOH for advice on local conditions, testing, interpretation, and options to reduce exposure. Do not assume that one treatment technology, price, or result applies to every well.
Verified Sources
- NYSDOH - Radon (fetched and read August 7, 2026)
- NYSDOH - Radon Mitigation (fetched and read August 7, 2026)
- NYSDOH - PFAS and Private Wells (fetched and read August 7, 2026)
This is general information, not legal, tax or accounting advice. Every situation is different. Talk to a licensed attorney, accountant or tax professional before you act.
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