Radon is easy to ignore because you cannot see or smell it, yet it is one of the most important health checks you can do for a Lafayette home. If you are buying, selling, or just planning updates, a quick test can prevent last-minute surprises and help you make clear decisions. In this guide, you will learn why radon is common in Boulder County, how to test the right way, what results mean, and how fixes work, including timelines and costs. Let’s dive in.
Why radon matters in Lafayette
Radon is a colorless, odorless radioactive gas that forms naturally in soil and rock. When it collects indoors, it increases the risk of lung cancer over time. The EPA reports that radon is the second leading cause of lung cancer in the United States.
Much of Boulder County, including Lafayette, falls in the EPA’s highest predicted radon category. The EPA map of radon zones shows large areas in Zone 1, where the average indoor radon level is predicted to be above 4.0 pCi/L. Colorado’s geology also tends to produce elevated radon compared with many states. You can find statewide guidance and local contacts through the Colorado Department of Public Health & Environment (CDPHE).
Any foundation type can have elevated levels. Basements, slabs, and crawlspaces can all draw soil gas indoors, and the lowest lived-in level often shows the highest reading. The only way to know your home’s level is to test.
How to test your home
Short-term vs. long-term tests
Short-term tests run 2 to 7 days using charcoal canisters, electret detectors, or continuous radon monitors. They are ideal for a quick screen or during real estate inspections. Long-term tests run for 90 days or more and give a better estimate of your annual average because they capture seasonal swings. The EPA’s radon guidance outlines both approaches.
If you need a fast answer for a contract deadline, start with a short-term test. If you want the most reliable picture of exposure, run a long-term test that includes colder months.
Where and how to place a test
Test the lowest level of the home that you use regularly. If you have a finished basement that you use as living space, start there. You can also test the first floor to compare.
For short-term tests, keep “closed-house” conditions: close windows and exterior doors for at least 12 hours before and during the test, except for normal entry and exit. Place the device 20 inches to 6 feet above the floor, away from drafts, exterior walls, direct sun, heat sources, and high humidity areas. Do not place monitors in kitchens, bathrooms, crawlspaces, attics, or unconditioned areas.
When to hire a certified pro
For paid testing and mitigation, choose certified professionals. The National Radon Proficiency Program (NRPP) lists certified testers, mitigators, and accredited labs. Certified pros follow accepted protocols, use calibrated equipment, and can help you interpret results.
Testing during a real estate transaction
Short-term tests are common during inspection periods. If timing allows, you can schedule a follow-up test or plan long-term testing after closing to refine the annual average. Buyers who want the best data may do a short-term test now and a long-term confirm later.
Make sense of results
The EPA action level is 4.0 pCi/L. At or above this level, the EPA recommends taking action. Because no level is risk-free, many experts suggest considering mitigation for results below 4, especially for long-term exposure or if anyone in the home is a smoker or has added health risks. See the EPA radon information for details.
- Short-term result above 4.0 pCi/L: You can move directly to mitigation planning or confirm with a follow-up test.
- Long-term average above 4.0 pCi/L: Plan to mitigate.
- Results between 2.0 and 4.0 pCi/L: Retest to confirm, ideally long-term, or consider mitigation based on your household’s risk and how you use the space.
Remember that radon levels vary by season, weather, and HVAC operation. Long-term testing gives the clearest picture of annual exposure.
Fixing elevated radon
Most common solution: ASD
The primary and most effective method is sub-slab depressurization, also called Active Soil Depressurization. A contractor installs a sealed pipe through the slab or from a lined crawlspace and vents soil gas outside above the roofline using a quiet in-line fan. This is the industry standard for houses with basements or slabs. For professional standards and best practices, see AARST guidance.
Properly designed systems often reduce radon by 50 percent to well over 90 percent. Reduction depends on your foundation, soil conditions, and installation quality.
Other options and when to use them
- Crawlspace encapsulation or ventilation can be used alone or combined with ASD.
- Sealing cracks and gaps helps the main system perform better, but sealing alone is not enough.
- Mechanical ventilation or a heat recovery ventilator can supplement ASD to lower indoor concentrations.
- Radon-in-water treatment applies only if you have a private well with elevated radon in water. Aeration or granular activated carbon are options for water, but they do not address soil gas entry.
Timeline to mitigate
- Scheduling and site visit: often 1 to 2 weeks depending on contractor availability.
- Installation: many single-family homes are completed in a day. Complex layouts may take longer.
- Permits and inspections: an electrical or building permit may be required. Your contractor typically handles permits, but confirm local requirements in Lafayette and Boulder County before scheduling.
- Post-installation testing: run a follow-up short-term test after the system operates for at least 24 to 72 hours. For a definitive result, add a long-term test of 90 days or more.
What it typically costs
In Colorado, straightforward single-family homes often fall around 1,000 to 3,000 dollars. More complex projects can exceed 4,000 dollars, and unusual cases may reach 6,000 dollars or more. Costs rise with block foundations, multiple zones, aesthetic pipe routing, attic runs, added electrical work, or difficult access.
Get multiple written estimates from NRPP-certified mitigators. Ask for the scope of work, expected reduction, warranty terms, references, and a clear plan for post-mitigation testing.
Radon and real estate deals
Sellers: get ahead of it
Test before listing to avoid surprises in escrow. If results are elevated, schedule mitigation and document the work. Early action builds buyer confidence, reduces renegotiation risk, and keeps your timeline intact.
Provide buyers with a post-mitigation test result and a simple operating guide for the system. Clean, complete documentation makes a strong impression and can smooth appraisal and underwriting questions.
Buyers: protect your timeline
Include a radon testing contingency that names the accepted protocol and the action level, identifies who pays for mitigation, and sets a timeline for install and re-testing. Use NRPP-certified testers and clear deadlines.
If the short-term test is above 4.0 pCi/L, you can request seller-paid mitigation with a post-mitigation verification test or negotiate a credit and handle mitigation after closing.
What to keep for your records
Sellers should assemble a neat package after mitigation:
- Pre- and post-mitigation test results, including dates, locations, and the lab or monitor used
- The mitigator’s written report with system description, fan model and serial number, and a diagram of pipe routing
- Copies of permits and inspection approvals, if applicable
- Warranty documents and installer contact information
- Photos of pipe routing and fan placement
Buyers should ask for a post-installation verification test and a quick checklist for monitoring the system. A simple U-tube manometer or continuous radon monitor provides ongoing assurance that the fan is working.
Simple checklists for Lafayette homes
Seller pre-listing checklist
- Test now using a short-term or long-term method.
- If elevated, schedule mitigation and keep all documentation.
- Retest after the system runs for at least 24 to 72 hours, then plan a long-term confirmation.
- Share clean, organized records with buyers and your agent.
Buyer due diligence checklist
- Add a radon testing contingency with an action level of 4.0 pCi/L.
- Use NRPP-certified testers and define timing for testing and any mitigation.
- If results exceed 4.0 pCi/L, negotiate mitigation or a credit and re-test after installation.
- For best data, plan a long-term test after closing.
Homeowner maintenance checklist
- Keep the mitigation fan running at all times. Check the manometer monthly and record readings.
- Investigate unusual fan noise, new cracks, or changes in readings. Call the installer if something seems off.
- If you have a private well, test for radon in water and consult a specialist if levels are high.
- Retest your home every few years or after major renovations.
Local resources
- Learn the basics of health risk, testing, and mitigation from the EPA’s radon hub.
- Find Colorado-specific guidance and any local kit programs through CDPHE radon resources.
- Hire certified pros using the NRPP directory.
- Review professional best practices through AARST.
Ready to take the next step?
If you are planning to buy or sell in Lafayette, a simple radon plan keeps your timeline on track and your family safer. I can help you coordinate testing, understand results, and negotiate smartly during a transaction. Let’s put a clear plan in place that fits your goals. Start the conversation with Unknown Company.
FAQs
What is radon and why is it common in Boulder County?
- Radon is a colorless, odorless radioactive gas that forms in soil and rock; much of Boulder County is in the EPA’s highest predicted radon zone, so testing is recommended for Lafayette homes.
How often should Lafayette homeowners test for radon?
- Test when you buy, sell, or renovate and retest every few years, since levels can change with seasons, weather, and home updates; long-term tests best reflect annual exposure.
What is the EPA action level for radon in homes?
- The EPA recommends taking action at 4.0 pCi/L or higher, and some households consider mitigation below 4.0 pCi/L to reduce long-term risk.
How quickly can radon mitigation be installed during escrow?
- Many single-family homes can be completed in one day after scheduling, with permits and follow-up testing adding time; plan for 1 to 2 weeks to coordinate with contractors.
Do finished basements always have higher radon levels?
- Not always; any foundation type can be elevated, but the lowest lived-in level often measures higher, which is why testing that level is recommended.
Will high radon levels stop my mortgage from closing?
- Radon typically does not block mortgage financing; lenders rarely mandate mitigation, though specific programs may have safety guidance, so check requirements early.
What documents should sellers provide after mitigation?
- Provide pre- and post-mitigation test results, the installer’s system report, permits and inspections if applicable, warranty documents, and installer certification details.
