Buying or selling in North Boulder and wondering if radon should be on your checklist? You are not alone. Many homes in Boulder County can have elevated radon, and it is easy to test and solve when you know the steps. This guide gives you a clear plan for testing, mitigation, and new construction features so you can move forward with confidence. Let’s dive in.
Radon basics and health context
Radon is a colorless, odorless radioactive gas that can enter a home through tiny openings in the foundation. Long-term exposure to high levels increases lung cancer risk. The U.S. EPA recommends taking action at 4.0 pCi/L or higher and lowering levels as much as possible below that number.
Why North Boulder should test
Boulder County’s geology can produce higher radon levels, and homes in North Boulder can vary block by block. Basements and crawlspaces are common pathways. Because two similar houses can test very differently, rely on a test for the specific home rather than neighborhood averages.
When to test a home
You should test in any real estate transaction. If you are selling, consider testing before you list so you can address issues ahead of offers. Plan to test:
- During due diligence when buying a home
- After installing a mitigation system to confirm performance
- After major renovations that affect the foundation or HVAC
- Every two years, or when occupancy or airflow changes
Short-term vs. long-term tests
Short-term tests run for 2 to 7 days and are standard during transactions. A continuous radon monitor administered by a certified tester provides reliable, time-stamped readings on a tight timeline.
Long-term tests run 90 days or more and give a stronger picture of the annual average. They are useful for ongoing household monitoring but are less practical when you are on a contract deadline.
If your first short-term test reads 4.0 pCi/L or higher, do a follow-up test to confirm before deciding on mitigation. Use certified measurement professionals for transaction testing.
Seasonal and setup tips
Radon can fluctuate daily and by season. Levels often read higher in colder months when homes are closed. Short-term tests are valid any time if you follow closed-house conditions and the device protocol. Continuous monitors that log hourly data help reduce uncertainty in fast-moving deals.
RRNC for new builds
Radon-Resistant New Construction, often called RRNC, is a set of simple, low-cost features built into new homes to prevent radon entry and make future upgrades easy. Typical components include:
- A gas-permeable layer under the slab
- A collection pipe that vents through the roof
- Sealed slab and utility penetrations
- A plastic vapor barrier over the sub-slab layer
- An electrical rough-in so a small fan can be added later
Local building departments may encourage or require RRNC in higher-risk areas. If you are building or buying new in North Boulder, confirm current requirements with the City of Boulder or Boulder County. Even when not required, adding a passive rough-in is smart insurance and can support resale.
What mitigation looks like
The most common method is active sub-slab depressurization. A discreet fan and pipe create lower pressure under your slab so soil gas stays out. Other methods, like crawlspace ventilation and sealing, can complement the system when needed.
When properly designed and installed, mitigation usually reduces indoor levels from above 4.0 pCi/L to well below that number. Always verify performance with a post-mitigation test.
Cost, timing, and disruption
- Typical cost: about $800 to $3,000 nationally, with many single-family homes around $1,200 to $2,000. Expect Boulder pricing to trend toward the higher end due to local labor and permit costs.
- Timeline: many systems install in 4 to 8 hours, often in one day.
- Disruption: light drilling, sealing, and exterior fan mounting. Most owners remain in the home during installation.
- Verification: run the system continuously. Confirm with a short-term test after 24 to 48 hours of operation, then consider long-term monitoring for everyday living.
Documentation buyers and sellers should keep
Strong documentation helps your transaction and protects value. Keep:
- Post-mitigation test results with dates
- Contractor scope, fan model and serial number
- Permit records when applicable
- Any RRNC details or prior test reports
Seller checklist: pre-listing
- Test before you go live. If results are ≥ 4.0 pCi/L, mitigate and keep the post-mitigation report ready for buyers.
- If your home already has RRNC or an active system, gather documentation and place it in your disclosures packet.
- Price and position your home confidently with clear test history to reduce negotiation friction.
Buyer checklist: due diligence
- Include a radon testing contingency with a clear protocol and timeline.
- Use a certified tester with a continuous radon monitor when possible.
- If results are elevated, negotiate seller-paid mitigation, a price reduction, or a credit, and require a post-mitigation test.
- Ask whether the home has RRNC rough-ins or an existing system and request supporting documents.
Choosing the right pro in Boulder
Select a certified radon measurement professional and a certified mitigator. Look for NRPP or similar credentials and membership in recognized professional associations. Ask for recent North Boulder references, proof of insurance, sample reports, and clarity on permits. Check with the City of Boulder or Boulder County to confirm current permitting and any RRNC requirements before work starts.
Smart contract language
Clear terms save time. Common buyer protections include the test type, tester certification, testing window, an action level of 4.0 pCi/L, and defined remedies such as seller-paid mitigation and a post-mitigation result at or below the action level. Sellers can streamline negotiations by sharing recent test results and any mitigation documentation up front.
The bottom line for North Boulder
Radon is manageable. With the right test, a proven mitigation approach, and clean documentation, you can protect health, reduce uncertainty, and keep your transaction moving. If you want a discreet, step-by-step plan that aligns with your goals and timeline, we are here to help.
Ready to create a radon-ready strategy for your purchase or sale in North Boulder? Schedule a private conversation with Unknown Company to align testing, timelines, and negotiation terms with your next move.
FAQs
What is radon and why should North Boulder owners care?
- Radon is a natural radioactive gas that can enter homes through the foundation, and long-term exposure at high levels raises lung cancer risk. Testing confirms if a specific home needs action.
What radon level requires action in a home purchase?
- The EPA recommends mitigation at 4.0 pCi/L or higher. Many buyers use that threshold in contracts and ask for a post-mitigation test at or below that level.
Which test should I use during due diligence?
- A short-term test using a continuous radon monitor by a certified tester is common for transactions because it delivers reliable results on a tight schedule.
How much does mitigation usually cost in Boulder?
- Many homes fall in the range of about $1,200 to $2,000, with a broader national range of $800 to $3,000. Local labor and permit costs can push Boulder toward the higher end.
How long does mitigation take and how do I verify it worked?
- Many systems install in one day. Run the fan continuously and confirm with a short-term follow-up test after 24 to 48 hours, then consider long-term monitoring.
What is RRNC and should I spec it for a new build?
- Radon-Resistant New Construction includes passive features like a vent stack, vapor barrier, and sealing that make prevention easier and allow a simple fan upgrade later. It is a smart, low-cost add for North Boulder builds.
