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Radon mitigation in Denver typically costs between $800 and $2,500 for a standard residential installation, with most homes landing around $1,200. Foundation type, system complexity, and home size are the main cost drivers.
Why Radon Costs Matter More in Denver Than Most Cities
Denver sits in EPA Zone 1 — the highest radon-risk category. Colorado’s bedrock is rich in uranium-bearing granite and gneissic formations, and as that uranium breaks down naturally, it releases radon gas that moves upward through soil and into homes. We typically see roughly half the Denver metro homes we test come back above the EPA action level of 4.0 picocuries per liter (pCi/L).
Colorado’s statewide indoor radon average runs around 6.3 pCi/L — well above the 4.0 pCi/L threshold where mitigation becomes necessary. That number isn’t a scare tactic; it’s a reflection of the geology under this city.
Denver’s cold winters make this worse. Homes seal up tight from October through March, and the stack effect — the natural pressure difference between warm indoor air and cold outdoor air — pulls soil gases like radon upward into living spaces more aggressively. Radon levels that seem manageable in July can look very different in February.
What Factors Drive the Cost of a Mitigation System?
A standard sub-slab depressurization system runs $800–$2,500 for most Denver homes, with the average closer to $1,200.
Sub-slab depressurization is the most common mitigation method. A contractor cores through the foundation slab, inserts a PVC pipe, connects a fan, and routes the pipe to the exterior — usually through the garage or up the side of the house. The fan runs continuously, drawing radon from beneath the slab and exhausting it outside before it can enter the home.
Several things can move that price up or down:
- Foundation type — Slab-on-grade homes are usually the most straightforward. Crawl spaces require a vapor barrier over exposed soil, which adds $200–$500 to the job. Homes with both a basement and a crawl space may need multiple suction points.
- Number of suction points — Some homes need only one pipe penetration; others with complex slab sections or multiple additions need two or three. Each additional point adds roughly $200–$350.
- Electrical work — The mitigation fan needs power. If a dedicated outlet isn’t already near the installation point, electrical work averages around $349 separately.
- Existing RRNC features — Newer Denver homes built with radon-resistant new construction (RRNC) features — a passive pipe already stubbed through the slab — are cheaper to upgrade. Activating a passive system by adding a fan typically costs $300–$500.
How Do Testing Costs Factor Into the Total?
Testing is the step before mitigation, and it matters — you shouldn’t pay for a system without confirmed elevated levels.
A DIY charcoal canister short-term test runs $15–$40 at most hardware stores. You leave it in the lowest regularly occupied level of the home for two to seven days under closed-house conditions, then mail it to a lab. Results come back within a week. This is a reasonable first screen, and it’s what most Denver homeowners start with before deciding on mitigation.
Professional short-term testing using a continuous radon monitor (CRM) costs $150–$250 and gives you real-time data rather than a single snapshot. Long-term tests — 90 days or more — run $25–$60 as a DIY kit and give a more accurate picture of year-round exposure.
One note on summer testing: open windows can temporarily dilute indoor radon, which means a summer reading may underestimate what you’ll see in winter. If you’re testing now and results come back between 2.0 and 3.5 pCi/L, a follow-up long-term test is worth doing before assuming you’re in the clear.
What Does Annual Maintenance Cost After Installation?
Once a system is installed, ongoing costs are minimal — usually $0–$150 per year.
The main thing to check is the U-tube manometer, a small fluid-filled gauge mounted on the pipe that shows whether the fan is creating suction. If the fluid levels are uneven, the system is working. If they’re level, the fan may have failed. Most homeowners can read this themselves after a contractor explains it at installation.
Fan replacement is the main repair cost. Mitigation fans typically last 10–20 years. Replacement fans cost $75–$200 for the unit, plus labor if you’re not comfortable doing it yourself. Some contractors include an annual system inspection for under $100, which is worth it for peace of mind.
How Does Denver Compare to a DIY Mitigation Approach?
| Approach | Typical Cost | Time to Complete | Key Limitation |
|---|---|---|---|
| DIY short-term test kit | $15–$40 | 2–7 days + lab time | Screening only, not diagnostic |
| Professional CRM test | $150–$250 | 48–72 hours | Adds cost but gives more detail |
| DIY mitigation system | $500–$1,000 | 1–2 days | Improper install can increase levels |
| Professional mitigation (standard) | $800–$2,500 | 4–8 hours | Requires licensed contractor |
| Fan replacement (maintenance) | $75–$350 | 1–2 hours | DIY-possible for handy homeowners |
| Annual system inspection | $0–$150 | 1 hour | Often included with installation warranty |
DIY mitigation kits exist, but in our experience they’re a reasonable option only for very simple slab-on-grade homes with straightforward soil conditions. Denver’s geology isn’t always cooperative — some areas have fractured soil or gravel sub-bases that don’t respond the way a standard install expects. A licensed contractor can diagnose sub-slab conditions before committing to a single suction point location.
When Should You Call a Licensed Professional?
Call a licensed radon professional if your test results are at or above 4.0 pCi/L, or if you’re buying or selling a home. Colorado requires radon disclosure in real estate transactions as of August 2023, so documented test results matter.
Signs that professional mitigation is the right call — not DIY:
- Results above 4.0 pCi/L on any floor level
- A crawl space with no existing vapor barrier
- Results that vary widely between floors (indicates complex entry points)
- A home with multiple foundation types (basement plus addition on slab, for example)
- Any reading above 8.0 pCi/L, which warrants scheduling within weeks, not months
Colorado requires radon contractors to hold licensure through the Department of Regulatory Agencies (DORA) and carry professional liability insurance. Ask to see both before work begins. A legitimate contractor will also retest after installation to verify the system brought levels below 4.0 pCi/L — ideally below 2.0 pCi/L.
If you’re unsure whether your levels actually require action, understanding the specific thresholds for Denver homes can help you make that call with confidence.
What Should Denver Homeowners Do Next?
If you haven’t tested, start there. Pick up a charcoal canister test or schedule a professional CRM test. Run the test in the lowest regularly occupied level — basement, finished lower level, or ground floor — away from windows, exterior doors, and high-humidity areas.
If results come back at 2.0 pCi/L or higher, do a follow-up long-term test or move directly to professional assessment. If you’re above 4.0 pCi/L, start scheduling mitigation. Most professional installs in the Denver metro are completed in a single day — four to eight hours is typical for a standard system.
Keep your test results. You’ll need them for any future real estate transaction, and they establish a baseline to compare against post-mitigation retesting.
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FAQ
Q: Does the age of my Denver home affect radon mitigation cost?
Somewhat. Newer homes built with RRNC features cost less to upgrade — around $300–$500 to activate. Older homes without passive systems typically fall in the standard $800–$2,500 range.
Q: How long does a radon mitigation installation take?
Most standard residential installs in Denver take four to eight hours. Complex homes with multiple foundation types or extra suction points may run a full day.
Q: Can I get financial help paying for radon mitigation in Colorado?
Yes. The Colorado Low Income Radon Mitigation Assistance Program provides up to $1,500 for qualifying owner-occupied homes. Income guidelines apply — contact CDPHE for current eligibility details.
Q: Will my mitigation system work year-round in Denver’s climate?
Yes. Systems are designed for continuous operation and handle Colorado winters without issue. Fan units are weatherproofed and typically rated for 10–20 years of service.
Q: How soon after installation can I retest radon levels?
Wait at least 24 hours after system activation before retesting. Most contractors recommend a 48-hour closed-house short-term test to verify the system brought levels below 4.0 pCi/L.
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Sources
- U.S. Environmental Protection Agency: Radon mitigation standards, action levels, and consumer testing guidance
- Colorado Department of Public Health and Environment: Radon program guidelines, Low Income Radon Mitigation Assistance Program, and state average radon data
- Colorado Department of Regulatory Agencies (DORA): Radon contractor licensing requirements
- Colorado Geological Survey: Colorado geology and radon occurrence patterns
- Colorado Environmental Public Health Tracking: Radon disclosure requirements and real estate transaction rules
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RadonSweep helps Denver homeowners connect with licensed radon professionals who know Colorado’s geology, building codes, and what realistic mitigation looks like in this specific market. If your test results are in and you’re ready to understand your next steps, RadonSweep is a practical place to start.