Radon Zone Report logo RadonZoneReport

The risk
you can't see.

Colourless. Odourless. Radioactive. The EPA attributes 21,000 US lung-cancer deaths to indoor radon every year, second only to smoking. Type a ZIP; get a plain-English dossier of the radon risk under your floor.

Pull my report · $15 Instant PDF · EPA & AARST sources
EPA-402-R-93-071 · 3,143 counties covered · AARST SGM-SF-2017

Before your buyer's inspector says the word.

Handed to a listing agent, a home inspector, or a renovation contractor before radon becomes a negotiation. No account. No newsletter. No mitigator affiliation.

  • EPA Radon Zone (1, 2, or 3) for the county
  • Expected indoor average concentration (pCi/L)
  • How the county compares against its neighbours
  • Mitigation cost band, AARST-aligned
  • When to test, and what to ask your inspector
  • Every number linked to its EPA source, so it can be checked
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A real report.

The dossier for ZIP 80302 — Boulder County, Colorado. Zone 1. Front Range granites. Your county replaces every field below.

REPORT · RR-80302

Boulder County, Colorado

ZIP 80302 · Front Range · 5,430 ft elevation
EPA Zone
1
Highest risk
Expected indoor average
4.3 pCi/L
Above the 4.0 EPA action level.
EPA action level
4.0 pCi/L
Mitigation recommended at or above.
Mitigation cost
$1,200–$2,500
Sub-slab depressurization (typical).
Re-test cadence
Every 2 yrs
Or after any basement remodel.

Findings

Boulder County sits on uranium-rich granitic and metamorphic bedrock of the Colorado Front Range. The EPA classifies this county as Zone 1, the highest of the three risk tiers, meaning the predicted average indoor radon screening level exceeds 4 pCi/L. Colorado state-wide screening averages reported by the Colorado Department of Public Health & Environment sit above the EPA action level, and Boulder County is among the elevated Front Range counties.

Recommended action

If your home has not been tested in the past 24 months, test now using a short-term kit (3–7 days) in the lowest livable level. If results return ≥4.0 pCi/L, commission a quote from a certified mitigator (NRPP or NRSB). Sub-slab depressurisation, the standard intervention, typically runs $800–$2,500 and reduces indoor concentrations by 50–99% per the EPA Consumer's Guide to Radon Reduction.

Sources

  • US EPA, Map of Radon Zones, Colorado (EPA-402-R-93-071)
  • EPA Citizen's Guide to Radon (EPA-402-K-12-002)
  • Colorado Dept. of Public Health & Environment, Radon Program
  • AARST-NRPP, Soil Gas Mitigation Standard SGM-SF-2017
02

A page an inspector can read in ten seconds.

Your county's EPA zone, the expected indoor average, your home's likelihood of testing above the action level, the mitigation cost band, and the lifetime-risk numbers, on one printable page. Hand it to a buyer's inspector or a realtor and the radon question is answered before it turns into a negotiation.

03

It holds up when someone checks it.

  • The zone is the EPA's own classification, cited on the page. Your realtor can look it up in a minute.
  • The lung-cancer risk figures are the EPA's numbers, not a scary stat invented to push a sale.
  • Where your state's survey is newer than the 1993 EPA map, you get the state's measurement instead of a 30-year-old estimate.
  • Cost ranges come from EPA and American Lung Association guidance, not a mitigation company's quote.
04

How this report is built.

Read this before ordering. It is the reason we sell a PDF rather than an assurance.

Primary sources

  • EPA Map of Radon Zones (EPA-402-R-93-071). County-level zone (1/2/3) classifications.
  • EPA Assessment of Risks from Radon in Homes (EPA-402-R-03-003), Table A-1. Lifetime lung-cancer deaths per 1,000 by exposure level.
  • EPA Citizen's Guide to Radon (EPA-402-K-12-002). Action level, testing cadence, mitigation principles.
  • EPA Consumer's Guide to Radon Reduction (EPA-402-K-10-005). Mitigation system types and effectiveness ranges.
  • NRPP & NRSB certification directories, used for "find a mitigator" pointers, not for any vetting claim.
  • State radon programs (CDPHE, Iowa DPH, PA DEP, etc.) for state-level screening averages.

What's in the number

  • Your zone comes from the EPA county-level map, with a hand-curated set of county overrides where state-published data is more precise than the 1993 national map.
  • Your county average pCi/L is the published state or county screening average, not your home's reading.
  • Your "% likelihood ≥ 4 pCi/L" is a log-normal estimate calibrated against EPA national screening data, adjusted for basement (+8 pts) and home type. It is a population estimate, not a measurement.
  • Mitigation cost uses the EPA / American Lung Association range of $800–$2,500 for sub-slab depressurisation, adjusted modestly by zone.

Honest limits

The EPA Map of Radon Zones was published in 1993 and has not been re-issued; the county classifications are stable but actual home readings vary dramatically house-to-house on the same street. This report is a population-level statistical estimate for the county you specify. It is not a measurement of your home. The only way to know your home's radon level is to test it with a short-term ($15–$30) or long-term ($25–$45) kit. If your county has unusual geology, microclimate, or a recently-published state survey, treat the in-report figures as a starting point, not the last word.

Who builds it

Compiled by an independent research team using federally-published data. Not affiliated with or endorsed by the EPA, AARST, NRPP, NRSB, or any radon-mitigation business. We do not sell tests, mitigation systems, or referrals. We do not collect a commission from anyone you hire. We sell a $15 PDF.

Contact [email protected] Last reviewed June 2026 Guarantee Full refund if a figure is wrong or we can't build your report.
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