Last updated 2026-08-18
TL;DR
Colorado regulates radon mitigation through the Colorado Department of Public Health and Environment (CDPHE). Contractors must hold a state certification, which requires passing a nationally recognized exam (NRPP or NRSB), completing a state-approved course, and paying a certification fee. Homeowner mitigation jobs typically cost $800 to $2,500. There is no separate "radon board"; CDPHE's Indoor Environment Program runs the whole show.
Who actually oversees radon mitigation in Colorado?
Colorado has no standalone radon licensing board. The Colorado Department of Public Health and Environment (CDPHE), specifically its Indoor Environment Program, handles certification for radon testers and mitigators [1]. That program operates under authority granted by the Colorado Revised Statutes. If you're trying to figure out who to call, who to file with, or whose rules govern your work, that's the agency.
The Indoor Environment Program publishes the approved course list, maintains the public database of certified contractors, and processes certification applications. There's no separate board meeting you can observe or petition. Rulemaking goes through CDPHE's standard administrative process.
This matters because several other states (Illinois and Florida are good examples) do have named radon boards that operate with some independence. Colorado's structure is more consolidated. One agency, one contact point, one fee schedule. That simplicity is useful once you know where to look.
Do you need a license for radon mitigation in Colorado?
Yes. Colorado requires certification to perform radon mitigation services for compensation. Under CDPHE's radon program, anyone offering mitigation services commercially must hold a current state certification [1]. Working without one violates the program's requirements and can trigger a referral for enforcement.
The certification path for mitigators requires two things working together: (1) passing a nationally recognized proficiency exam, either through the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB), and (2) meeting CDPHE's training requirements, which means completing a state-approved radon mitigation course [2]. You can't just show up with an NRPP card and skip the state paperwork, and you can't take a course and skip the exam either.
Homeowners doing their own mitigation in their own single-family home sit in a different category. State certification requirements target commercial contractors. That said, if you're planning to sell or rent the property, most buyers' agents and inspectors will want a certified contractor's post-mitigation test on file anyway. The practical pressure toward certified work is real regardless of the legal requirement.
Colorado is a high-radon state. EPA estimates roughly one in three Colorado homes has radon levels above the 4 pCi/L action level [4]. CDPHE takes the certification requirement seriously as a result.
What are the specific certification requirements CDPHE sets for mitigators?
CDPHE's Indoor Environment Program keeps the current certification requirements on its radon program page [1]. The core elements, which you should confirm directly with CDPHE since requirements do change, have historically included:
- Completion of an approved radon mitigation training course (typically a multi-day hands-on course from an NRPP- or NRSB-approved provider)
- Passing the NRPP or NRSB mitigation certification exam
- Submitting a completed CDPHE application form
- Paying the state certification fee (confirm current amount with CDPHE)
- Carrying appropriate general liability insurance (amount specified in program requirements)
Certification isn't permanent. Renewals run on a cycle set by CDPHE, and continuing education is part of keeping the credential current [2]. NRPP requires 16 continuing education credits per two-year renewal cycle for its RMT (Radon Mitigation Technician) credential [2].
One thing new applicants often miss: the NRPP and NRSB credentials are national certifications that Colorado accepts as the exam component, but they don't replace the CDPHE application. You need both the national credential and the state paperwork. Confirm the exact current sequence with CDPHE's Indoor Environment Program before you schedule your exam.
How much does radon mitigation cost in Colorado?
For a typical single-family home, radon mitigation in Colorado runs roughly $800 to $2,500 for a sub-slab depressurization (SSD) system, the most common install type [3]. The EPA puts the national average around $1,200, and Colorado pricing tracks close to that midpoint [3].
Several factors move the price up or down:
| Factor | Typical cost impact |
|---|---|
| Single suction point, accessible slab | Lower end ($800-$1,100) |
| Multiple suction points needed | Add $200-$400 per additional point |
| Finished basement or difficult routing | Add $300-$700 |
| Crawl space requiring membrane | $1,500-$3,000 range |
| Post-mitigation radon test (by contractor) | $100-$200 typically included or added |
| Follow-up test by independent tester | $100-$300 separately |
Budget for the post-mitigation test separately. AARST-ANSI standards call for a post-mitigation test at least 24 hours after installation [5]. Some contractors include one; many don't. An independent test from a different certified tester gives you a cleaner result with no conflict of interest.
Colorado has no state rebate program for radon mitigation right now. Check with your local utility or county health department for local incentives, since those programs come and go.
The EPA's radon program puts typical mitigation costs at roughly $800 to $2,500, with most homeowners paying around $1,200 [3].
How long does radon mitigation take in Colorado?
The installation itself is usually a one-day job. A straightforward sub-slab depressurization system on a typical Colorado home takes a certified contractor two to six hours [3]. You're home that day, the fan is running by evening.
What takes longer is the testing sequence. Before you can confirm the mitigation worked, you need a post-mitigation test. Short-term tests run 48 to 96 hours. Long-term tests run 90 days or more and give a more reliable picture of annual average exposure [6]. Most real estate transactions and contractor warranties use a short-term post-mitigation test for speed, but CDPHE recommends long-term testing for the most accurate reading.
Here's the realistic timeline from scheduling a contractor to confirmed results:
- Contractor scheduling: 1 to 3 weeks out, depending on season and backlog
- Installation day: 1 day
- Post-mitigation short-term test: 2 to 4 days
- Lab results: 1 to 5 business days depending on the lab
Total elapsed time: commonly two to five weeks from first call to final confirmed reading. In a fast-moving real estate deal, start this process the moment inspection results come back, not after the mitigation addendum is signed.
What radon levels trigger action in Colorado, and why is the state considered high-risk?
The EPA action level is 4 picocuries per liter (pCi/L). EPA also recommends considering mitigation at 2 to 4 pCi/L, particularly for children and long-term residents [3]. CDPHE follows these federal thresholds.
Colorado's geology is the reason the state gets special attention. The state sits on uranium-rich soils and granite formations, particularly along the Front Range and across many mountain counties. EPA's map of radon zones places most of Colorado in Zone 1, the highest predicted average indoor radon level (above 4 pCi/L) [7]. That doesn't mean every home is over the limit, but the base risk is elevated compared to coastal states.
CDPHE has tested thousands of Colorado homes and publishes county-level data [8]. Some mountain counties show median levels well above 4 pCi/L. Denver metro averages run higher than the national average. Work in Colorado long enough and you'll meet clients who've never tested and have lived in 8 or 10 pCi/L homes for years without knowing it. That's the practical reality that drives demand for certified mitigators here.
How does CDPHE's radon certification compare to other states?
Colorado's approach sits in the middle of the national spectrum. States like Illinois, Florida, and Connecticut run more formalized licensing structures with named boards, dedicated statutes, and sometimes higher fees. States like Idaho and Arizona keep minimal state-level requirements and lean almost entirely on the national credentials (NRPP or NRSB) with no extra state paperwork.
Colorado requires state certification on top of the national credential, puts CDPHE in charge of enforcement, and maintains a public contractor database. That's more structured than the no-regulation states and less bureaucratic than the board-heavy states. The practical effect for contractors: you're doing two applications (national credential plus state certification), but you deal with one agency instead of a board plus a licensing division plus an exam board.
For consumers, the CDPHE contractor lookup is the right verification tool. Always check a contractor's state certification status before signing, more than their NRPP card. The national credential and the state certification are separate things, and a contractor can have one without the other.
If you operate across state lines, note that each state runs its own program. Colorado certification doesn't carry over to Kansas or Utah without those states' own processes. Compare state structures at radon mitigation board in Arizona, radon mitigation board in Idaho, or radon mitigation board in Illinois to see how different states handle the same requirement.
What training courses does CDPHE approve for mitigators?
CDPHE accepts courses approved by NRPP or NRSB, since those are the national bodies whose exams Colorado requires [2]. You don't pick from a CDPHE-specific course list the way some states run their own approved providers. You find an NRPP- or NRSB-approved radon mitigation training course, complete it, pass the exam, then bring that credential to your CDPHE application.
NRPP-approved mitigation courses come from several providers nationally, including in-person options in Colorado and online/hybrid formats. Course length varies. The NRPP-approved mitigation curriculum typically covers sub-slab depressurization design, fan selection, diagnostic testing, system installation, post-mitigation verification, and record-keeping. Hands-on field time is a component of most approved courses, more than classroom hours.
The NRSB runs a parallel structure with its own approved training list. Both NRPP and NRSB are recognized by EPA and accepted by CDPHE. Which one you choose often comes down to where the training provider sits and which exam has a test center closer to you.
If you want to understand how the national credential requirements break down before committing to a training program, the RadonPath NRPP Mitigation Kit at /start walks through the NRPP application path and documentation requirements. That's the national piece; you'll still complete CDPHE's state application separately.
What does it cost to get and renew a Colorado radon mitigation certification?
There are two layers of cost: the national credential and the state certification.
For the NRPP Radon Mitigation Technician (RMT) credential, the application and exam fees are set by NRPP and have historically run a few hundred dollars combined, though NRPP adjusts its fee schedule periodically. Confirm current NRPP fees directly with NRPP [2].
For the CDPHE state certification, there's a separate application fee. Confirm the current amount with CDPHE's Indoor Environment Program [1], since state fees change and a stale number here would do you more harm than good.
Renewal costs recur on CDPHE's certification cycle and on NRPP's two-year renewal cycle. NRPP renewal requires 16 CEUs per two-year period plus a renewal fee [2]. CDPHE renewal requires you to keep the national credential in good standing, so if your NRPP credential lapses, your state certification is at risk.
Insurance is a real cost too. Colorado, like most states, specifies a minimum general liability coverage for certified radon contractors. The required amount lives in CDPHE's program requirements; confirm it, then get quotes from contractors' liability insurers. Radon contractor insurance isn't exotic, but not every general liability policy covers it without an endorsement.
Budget separately for training (course tuition ranges widely, from roughly $500 to $1,500 or more for in-person courses with materials), exam fees, state certification fees, and insurance. Your all-in first-year cost before you turn a wrench on your first job is realistically $1,500 to $3,000 depending on provider and insurance market.
What standards govern the actual installation work in Colorado?
Colorado certified mitigators follow AARST-ANSI standards for radon mitigation system design and installation [5]. The primary standards are AARST-ANSI CCAH (Reducing Radon in New Construction of 1 and 2 Family Dwellings and Townhouses) for new construction and AARST-ANSI SGM (Soil Gas Mitigation Standards for Existing Homes) for retrofits.
These standards cover system design, fan placement, suction point location, electrical requirements, labeling, and post-installation verification testing. They're not suggestions. CDPHE ties contractor certification to adherence to these standards, and a substandard installation is grounds for complaints and potential decertification.
If you're a consumer trying to judge whether a contractor's proposed system is legitimate, AARST-ANSI standards are publicly available for purchase and give you the technical baseline. At minimum, ask any contractor you're considering: are they following AARST-ANSI standards, will they label all components of the system, and will they include a post-mitigation test? Contractors who can't answer those clearly are a red flag.
AARST-ANSI mitigation standards require a post-mitigation diagnostic test after system installation [5]. That's not optional. If a contractor installs and walks away without a post-test, they haven't completed the job per the standard.
How do you verify a contractor is actually certified in Colorado?
CDPHE keeps a public list of certified radon contractors on its Indoor Environment Program website [1]. That's your first stop. Search by name or company, and confirm the certification type (testing vs. mitigation) and expiration date.
Check the NRPP or NRSB database as a second verification. NRPP's Find a Professional tool lets you search by state and credential type [2]. A legitimate certified mitigator shows up in both places: CDPHE's state list and their national credentialing body's directory.
When you call a contractor, ask directly: what is your CDPHE certification number, and is your NRPP or NRSB credential current? Any contractor who hesitates or can't give you a certification number on the spot is worth questioning further.
For contractors new to Colorado who want to see how neighboring states handle the same verification question, the comparison helps. Radon mitigation board in Arizona and radon mitigation board in Idaho show two states with lighter regulatory structures that lean on national credential lookups rather than state databases.
Where to start if you're entering the radon mitigation field in Colorado
Here's the realistic sequence for someone starting fresh:
1. Go to CDPHE's Indoor Environment Program page and download the current certification requirements and application form [1]. Read it before you do anything else. Requirements change, and you want the live version.
2. Find an NRPP- or NRSB-approved mitigation training course and schedule it. In-person courses fill up; some popular providers book out several weeks ahead.
3. Pass the national exam (NRPP RMT or NRSB equivalent) and get your credential issued.
4. Assemble your CDPHE application package: completed form, copy of your national credential, proof of insurance, and the state certification fee.
5. Submit to CDPHE and follow up. Processing time varies; confirm expected turnaround with the agency when you submit.
For the national credential piece, RadonPath's NRPP Mitigation Kit at /start helps new applicants understand what NRPP wants and avoid common application mistakes. It covers the paper path, not the installation itself.
Don't skip the insurance step before you apply. CDPHE requires proof of coverage, and shopping for contractor liability insurance takes time if you've never done it. Get those quotes running in parallel with your course enrollment.
Other state guides worth a look for comparison: radon mitigation board in Florida, radon mitigation board in Illinois, and radon mitigation board in Connecticut.
Frequently asked questions
Do you need a license for radon mitigation in Colorado?
Yes. Colorado requires state certification from CDPHE's Indoor Environment Program to perform radon mitigation for compensation. You must complete an approved training course, pass an NRPP or NRSB mitigation exam, carry required insurance, and submit a state application with fee. Working commercially without a valid CDPHE certification violates the program's requirements. Homeowners doing work on their own single-family home are generally not subject to the commercial certification rule.
How much does radon mitigation cost in Colorado?
Most single-family homes in Colorado pay $800 to $2,500 for a sub-slab depressurization system. The EPA puts the national average around $1,200, which tracks with Colorado midrange pricing. Crawl spaces and homes needing multiple suction points cost more. A post-mitigation test typically adds $100 to $300 if done by an independent certified tester. Colorado has no statewide rebate program for mitigation at this time.
How long does radon mitigation take in Colorado?
Installation itself takes two to six hours for a typical home. But from first call to confirmed results, plan on two to five weeks: one to three weeks to get a contractor scheduled, one day for installation, two to four days for a short-term post-mitigation test, and a few days for lab results. In real estate transactions, start the process immediately after inspection; don't wait until the mitigation addendum is countersigned.
Which agency runs radon certification in Colorado?
The Colorado Department of Public Health and Environment (CDPHE), through its Indoor Environment Program, manages radon contractor certification. There is no separate radon board. CDPHE sets requirements, processes applications, maintains the certified contractor database, and handles complaints. Their Indoor Environment Program page is the authoritative source for current fees, forms, and requirements.
Does Colorado accept the NRPP or NRSB national credential in place of state certification?
No. Colorado accepts NRPP and NRSB credentials as the exam and training component of your application, but you still must complete a separate CDPHE state certification application, pay the state fee, and maintain active state certification. The national credential and state certification are two different things. You need both. Verify the current application sequence with CDPHE's Indoor Environment Program before submitting.
How often does a Colorado radon mitigation certification need to be renewed?
CDPHE sets its own renewal cycle; confirm the current period directly with the agency. Your national credential (NRPP or NRSB) renews on a separate schedule. NRPP's RMT credential requires renewal every two years with 16 continuing education units. If your national credential lapses, your state certification is at risk. Set reminders for both deadlines independently.
What is the radon action level in Colorado?
Colorado follows EPA's guidance: the action level is 4 pCi/L, and EPA recommends considering mitigation between 2 and 4 pCi/L. Most of Colorado sits in EPA's Zone 1, the highest predicted average indoor radon level category, due to uranium-rich soils and granite geology along the Front Range and mountain regions. CDPHE recommends all Colorado homes be tested.
Is a post-mitigation test required in Colorado?
AARST-ANSI standards, which CDPHE-certified contractors follow, require a post-mitigation diagnostic test after system installation. Some contractors include this; others charge separately. Either way, budget for an independent post-mitigation test from a separately certified tester to confirm the system is working without any conflict of interest.
Can a homeowner in Colorado do their own radon mitigation?
State certification requirements target commercial contractors doing mitigation for compensation. A homeowner working on their own single-family home is generally not required to hold CDPHE certification. However, any self-installed system still needs to work. If you plan to sell, most buyers will want a post-mitigation test signed off by a certified contractor. DIY mitigation is legally permissible in most cases but practically limiting for resale.
How do I verify a contractor is certified in Colorado?
Check CDPHE's public certified contractor database on the Indoor Environment Program website. Then cross-check the contractor's NRPP or NRSB credential using those organizations' online Find a Professional tools. Ask the contractor for their CDPHE certification number directly. A legitimate certified mitigator can provide both their state certification number and national credential status without hesitation.
What insurance does a Colorado radon mitigator need?
CDPHE requires proof of general liability insurance as part of the certification application. The minimum required coverage amount is specified in the program's current requirements; confirm that figure with CDPHE before you shop for a policy. Not every general contractor liability policy covers radon work without a specific endorsement, so be explicit with your insurer about what you're doing.
Does Colorado have a radon disclosure requirement for home sales?
Colorado does not have a specific statute requiring sellers to disclose radon test results, but the standard Colorado real estate contract includes a provision for radon inspection and mitigation. In practice, radon testing and mitigation are common contingencies in Colorado transactions, especially along the Front Range. Buyers should request testing; sellers should expect it. Confirm current disclosure norms with a Colorado real estate attorney.
What's the difference between radon testing certification and mitigation certification in Colorado?
CDPHE certifies radon professionals separately for testing and mitigation. A certified radon measurement provider (tester) and a certified radon mitigation contractor hold different credentials with different training and exam requirements. Some professionals hold both. If you're a mitigator, you cannot provide the independent post-mitigation test your own installation needs; you need a separately certified tester for that verification.
Sources
- Colorado CDPHE, Indoor Environment Program, Radon Program: CDPHE's Indoor Environment Program operates Colorado's radon certification program, sets contractor requirements, and maintains the certified contractor database
- National Radon Proficiency Program (NRPP): NRPP RMT credential requires passing the mitigation exam and renews every two years with 16 continuing education credits
- EPA, Radon: EPA states mitigation costs typically range from $800 to $2,500 with a national average around $1,200; EPA action level is 4 pCi/L
- EPA, Health Risk of Radon: EPA estimates approximately one in three Colorado homes has radon levels above 4 pCi/L, reflecting the state's high-risk geological profile
- AARST Consortium on National Radon Standards: AARST-ANSI mitigation standards require a post-mitigation diagnostic test after system installation
- EPA, Radon: Long-term radon tests run 90 days or more and provide a more reliable picture of annual average radon exposure than short-term tests
- EPA, Map of Radon Zones: Most of Colorado falls in EPA Zone 1, the highest predicted average indoor radon level category, due to uranium-rich soils and granite geology
- CDPHE, Colorado Radon Program Data: CDPHE publishes county-level radon test data showing elevated median levels in many Colorado counties, particularly in mountain and Front Range regions