Is radon a problem in Arizona? It can be, home by home. The Arizona Department of Health Services (ADHS) cites an EPA estimate that one in 15 Arizona homes has radon above 4.0 picocuries per liter (pCi/L). That's the level where EPA recommends action. EPA's map puts Maricopa County in Zone 2, moderate potential.
Does that mean your 85250 home has radon? Not necessarily. The only way to know is a test. EPA says its zone map shouldn't be used to decide whether a home needs testing. ADHS puts it plainly: any home can have high levels, no matter where you live or when it was built. ADHS offers free test kits, so testing is simple whether you're buying or selling.
Data note: Radon levels and testing guidance come from ADHS and the EPA Map of Radon Zones (Arizona). Contract timing comes from the Arizona REALTORS resale contract sample (Nov. 2025). General information, not medical or environmental testing advice.
Radon Basics
Per ADHS:
- What it is: a naturally occurring radioactive gas
- Why it matters: the leading cause of lung cancer in non-smokers and the second-leading cause overall
- How you'd know: you wouldn't. It's colorless, odorless and tasteless, so you need a test
- Safe level: ADHS says there is no "safe" level
EPA's thresholds:
- 4 pCi/L or higher: fix the home
- 2 to 4 pCi/L: consider fixing
What the Arizona Map Shows
EPA Radon Zones
- Zone 1: predicted average above 4 pCi/L (highest potential)
- Zone 2: predicted average 2 to 4 pCi/L (moderate). Maricopa County is here, along with the rest of Arizona on EPA's map
- Zone 3: predicted average below 2 pCi/L (low)
The Fine Print
- The map dates to 1993 and is built from indoor readings, geology, aerial radioactivity, soils and foundation types
- EPA's own guidance: "All homes should be tested, regardless of zone designation"
- Your neighbor's result doesn't predict yours, ADHS says
Testing When You Buy in 85250
Under the Arizona REALTORS resale contract, the inspection period is 10 days by default. A radon test fits inside it if you plan ahead:
- Order early. An ADHS short-term kit takes 3-7 days, plus lab time after you mail it. Ask your inspector about on-site radon testing to keep results inside your deadline.
- Read the result against EPA's levels: 4 pCi/L or above, or the 2-4 range.
- Respond within the period: ask for mitigation, a credit, or a price change, or cancel if the result is a deal-breaker.
- Line it up with your other inspections. In older 85250 homes, buyers often book a plumber too; see our galvanized and polybutylene pipe guide.
Buying a Home With a Mitigation System
A mitigation system means someone tested, found a reason to reduce radon, and acted. Ask for:
- The original test result and date
- Installation records and the installer's name
- Any follow-up test after installation
- The fan's location and confirmation that it's running
Then consider a new test during your inspection period to confirm the system is still doing its job.
For Sellers
- Disclose what you know. If you've tested or mitigated, include results and records with your disclosures; see our Arizona seller disclosure guide.
- Consider a pre-listing test. A free ADHS kit answers the question before a buyer asks it.
- If a buyer's test comes back high, you'll negotiate under the contract's inspection terms. Having a mitigation quote ready keeps the deal moving.
How Lower Levels Are Reached
ADHS publishes online guidance on what your results mean and how to decrease radon in your home. Use a qualified mitigation professional, keep the paperwork, and retest after any work so you, and your eventual buyer, have proof it worked.
“I'd much rather a client test and know than wonder. In 85250, radon rarely becomes a deal-breaker when it's handled early. A clear result, or a working system with records, is one more thing a buyer doesn't have to worry about, and one more thing a seller can show with confidence.”
— Elizabeth Vijan, Tackett Team, eXp Realty
FAQ: Radon in Arizona Homes
Is radon a problem in Arizona?
It can be. ADHS cites EPA's estimate that 1 in 15 Arizona homes tests above 4.0 pCi/L; Maricopa County is EPA Zone 2.
What radon level is safe?
ADHS says no level is "safe." EPA recommends fixing at 4 pCi/L or higher, and considering it at 2-4.
Should I buy a house with a radon mitigation system?
It can be a good sign. Get the records and retest during your inspection period.
How do I get a free radon test kit in Arizona?
Request a free short-term kit from ADHS online.
Buying or Selling in 85250?
I'll help you schedule the right inspections inside your deadlines and turn the results into a clear plan, whether you're making an offer or preparing to list.
Elizabeth Vijan | Tackett Team, eXp Realty
Chaparral Park Resident & 85250 Real Estate Expert
Plan My Inspections · Call or text 602-885-7752
Sources: ADHS: Radon testing and free test kits · EPA: Map of Radon Zones · EPA: Arizona radon zone map (PDF) · Arizona REALTORS sample resale contract, Nov. 2025 (PDF)
Disclaimer: General information, not medical, environmental or legal advice. Follow ADHS and EPA guidance and use qualified testing and mitigation professionals. Information deemed reliable but not guaranteed. Equal Housing Opportunity.
