Questions to Ask Before Hiring a Radon Contractor

The 30 minutes you spend asking the right questions before signing a radon mitigation contract is the cheapest insurance you'll buy on the install. This page is the question list, organized by stage of the hiring process.

Before any in-home visit:

1. "What's your DORA radon mitigation license number?"
2. "What's your NRPP or NRSB certification number?"
3. "How many years have you been doing mitigation in Colorado?"
4. "Do you service [your ZIP code] / [Colorado Springs neighborhood]?"
5. "What's your availability for an in-home assessment?"
6. "Do you charge for the assessment?" (Reputable mitigators don't.)
7. "Can you send me a sample written quote so I know what to expect?"

If a contractor can't or won't answer the first two questions over the phone, you have your screening result. Move on.

During the walkthrough of your home:

About your test result

• "Have you reviewed my test result? What level am I starting from?"
• "Does the test result tell you anything about the likely cause or pathway?"

About the foundation

• "What foundation type does my home have?" (Basement, crawlspace, slab, multi-zone — confirm they noticed every zone.)
• "Is there a sump pit or sump pump?"
• "Are there any obvious slab cracks, sealing issues, or foundation concerns I should know about?"

About the proposed system design

• "Will you run a pressure field extension (PFE) diagnostic before designing the system?" (Critical for multi-zone or tight-soil homes.)
• "How many suction points are you proposing? Why?"
• "Which fan model are you specifying? Why that model?"
• "How are you accounting for Colorado's altitude in fan sizing?" (Real contractors will have a specific answer involving 4% per 1,000 ft.)
• "Where will the pipe route — interior or exterior? Why?"
• "Where will the exhaust point be? Is that at least 10 feet above grade and 12 inches above the roof edge?" (Per AARST/EPA standards.)
• "Where will the manometer go? Will I be able to see it from a normal walking path?"

Once you have the written quote in hand:

• "Is the post-mitigation test included in the quoted price, or is it a separate line item?"
• "What's the target radon level for the post-mitigation test?" (Should be below 4.0 pCi/L; below 2.0 is ideal.)
• "What happens if the post-mitigation test doesn't bring levels below 4.0 pCi/L? Do you add another suction point at no charge?"
• "Is the electrical permit included? Who pulls it?" (Should be the contractor.)
• "Is drywall touch-up or paint match included if interior routing crosses a finished wall?"
• "What's your workmanship warranty? How long? In writing?"
• "What's the fan warranty? Manufacturer terms?"
• "How long will the install take? Will I need to be home?"

When you call the contractor's references:

• "When was your install? What was the result before and after?"
• "Was the install timeline what they promised?"
• "Has the manometer reading stayed stable since installation?"
• "Has the system needed any service calls?"
• "How did the contractor handle any issues that came up?"
• "Did the post-mitigation test come back as promised?"
• "Would you hire them again?"

References are typically curated by the contractor, so even cherry-picked references will give you signal — particularly on timeline reliability, communication, and post-install behavior.

• "What time does the crew arrive? How long will the install take?"
• "Do you need access to the basement, attic, and exterior wall?"
• "Will there be drilling / coring dust I need to clean up after?"
• "What kind of fan noise should I expect inside the house?"
• "How soon after install can I run the post-mitigation test?" (Should be 24+ hours of fan running.)
• "Who do I call if something goes wrong with the system after install?"