How to Reduce Radon in Tucson Homes

Radon is a colorless, odorless, and tasteless radioactive gas that forms naturally from the decay of uranium in soil, rock, and water. It can seep into homes through cracks in foundations, gaps around pipes, sump pits, and other openings—accumulating to dangerous levels indoors. In Tucson, Arizona, where geology includes uranium-rich granite and alluvial deposits, radon levels can be significantly elevated, particularly in homes built on or near bedrock formations. Long-term exposure to high radon concentrations is the second leading cause of lung cancer in the United States, after smoking. For Tucson residents, understanding how to reduce radon in homes is not just a matter of comfort—it’s a critical health imperative.

Unlike other indoor air pollutants, radon cannot be detected without specialized testing. Many homeowners in Tucson assume their homes are safe simply because they appear well-built or newly constructed. However, radon entry is not related to home age or maintenance level—it’s driven by geology, pressure differentials, and ventilation patterns. This guide provides a comprehensive, step-by-step approach to identifying, measuring, and mitigating radon in Tucson homes, grounded in scientific best practices and local environmental conditions. Whether you’re a homeowner, renter, or property manager, this resource will empower you to take informed, effective action to protect your household.

Step-by-Step Guide

Step 1: Test Your Home for Radon

The first and most essential step in reducing radon is to determine whether it is present—and at what concentration. The U.S. Environmental Protection Agency (EPA) recommends that all homes be tested, regardless of geographic location or construction type. In Tucson, where radon potential is classified as “Zone 2” (moderate risk) by the EPA, testing is especially critical due to localized variations in soil composition.

There are two primary types of radon tests: short-term and long-term. Short-term tests (typically 2–7 days) use charcoal canisters, electret ion chambers, or continuous monitors. These are useful for initial screening and are often used during real estate transactions. Long-term tests (90 days to one year) provide a more accurate annual average by accounting for seasonal fluctuations in radon levels, which can vary due to temperature, humidity, and HVAC usage.

To conduct a test, purchase a certified radon test kit from a state-approved vendor or order one through the Arizona Department of Health Services. Place the device in the lowest livable area of your home—such as a basement, ground-floor bedroom, or den—away from drafts, high humidity, and exterior walls. Follow the manufacturer’s instructions precisely: keep windows and doors closed during the test period, avoid using fans that exhaust air outdoors, and do not place the device in kitchens or bathrooms.

After the test period, send the device to the laboratory for analysis. Results are reported in picocuries per liter (pCi/L). The EPA action level is 4.0 pCi/L. If your result is at or above this level, mitigation is strongly recommended. Even levels between 2.0 and 4.0 pCi/L warrant consideration for reduction, as no level of radon exposure is considered completely safe.

Step 2: Confirm the Results with a Second Test

If your initial test indicates elevated radon levels, conduct a second test before proceeding with mitigation. This confirms the findings and rules out anomalies caused by unusual weather, occupancy patterns, or testing errors. Use a different testing method if possible—for example, if the first test was a short-term charcoal kit, use a long-term alpha-track detector for the follow-up.

Alternatively, hire a certified radon measurement professional to perform a continuous monitoring test. These professionals use calibrated digital devices that record hourly readings, providing a detailed profile of radon fluctuations over time. This data is invaluable for determining whether mitigation is needed and for selecting the most effective system design.

Step 3: Identify Entry Points

Radon enters homes primarily through pressure-driven airflow. The air pressure inside a home is typically lower than the pressure in the soil surrounding the foundation. This pressure difference acts like a vacuum, drawing radon gas upward through any available pathway.

In Tucson homes, common entry points include:

• Cracks in concrete slabs or foundation walls
• Gaps around service pipes, electrical conduits, or sump pumps
• Construction joints between walls and floors
• Porosity in block or stone foundations
• Well water (though less common in Tucson than in areas with high groundwater radon)

Conduct a visual inspection of your home’s foundation. Look for visible cracks, gaps, or crumbling mortar. Pay special attention to areas where utilities enter the home, such as water lines, gas pipes, or HVAC ducts. Use a flashlight to inspect crawl spaces and basements. If your home has a slab-on-grade foundation (common in Tucson), check for gaps around the perimeter where the slab meets the wall.

For a more thorough assessment, consider hiring a certified radon mitigation professional. They use smoke pens, pressure differential tests, and thermal imaging to pinpoint active entry pathways. Identifying these points is critical to designing an effective mitigation system.

Step 4: Choose the Right Mitigation System

The most effective and widely used method for reducing radon in Tucson homes is Active Soil Depressurization (ASD). This system works by installing a vent pipe and fan to draw radon from beneath the home and exhaust it safely above the roofline, where it quickly dilutes to harmless levels.

There are three primary types of ASD systems:

Sub-Slab Depressurization (SSD)

This is the most common and effective method for homes with concrete slabs. A hole is drilled through the slab, and a PVC pipe is inserted into the gravel or soil beneath. A fan connected to the pipe draws radon gas from below the slab and vents it outdoors. The system operates continuously and requires minimal maintenance.

Sub-Membrane Depressurization (SMD)

Used in homes with crawl spaces, this method involves covering the dirt floor with a high-density polyethylene membrane. A vent pipe and fan are then installed to draw radon from beneath the membrane and exhaust it outside. This method is highly effective in Tucson’s dry, arid climate, where crawl spaces are common and moisture control is already a priority.

Drain Tile Depressurization

If your home has a perimeter drain tile system (common in older Tucson homes), this can be adapted for radon mitigation. The drain tile is connected to a vent pipe and fan, effectively turning the drainage system into a radon collection network. This method is cost-effective when the existing infrastructure is intact.

In Tucson, where homes often sit on rocky or sandy soil, SSD is typically the preferred method due to its reliability and adaptability. However, a professional assessment will determine the optimal system based on your home’s foundation type, soil composition, and existing construction features.

Step 5: Install the Mitigation System

While some homeowners attempt DIY radon mitigation, it is strongly recommended to hire a certified radon mitigation specialist. Radon reduction systems require precise engineering to ensure proper airflow, pressure differentials, and venting. Incorrect installation can lead to ineffective results, increased energy costs, or even backdrafting of combustion gases.

A certified professional will:

• Perform a site assessment and choose the best system type
• Drill a suction point through the foundation or install a membrane
• Install a sealed PVC vent pipe (typically 3- or 4-inch diameter)
• Mount an in-line radon fan (usually in the attic or outside the living space)
• Route the pipe above the roofline, at least 10 feet above ground and 10 feet from windows or air intakes
• Seal all foundation cracks and entry points
• Test the system post-installation to verify performance

The entire process typically takes one to two days. Most systems are installed with a manometer—a U-shaped tube filled with liquid—that allows homeowners to visually confirm the fan is operating by observing the liquid level. The fan runs continuously and consumes minimal electricity (about the same as a 60-watt light bulb).

Step 6: Retest After Mitigation

After the system is installed, conduct a follow-up radon test to confirm effectiveness. The EPA recommends testing again within 30 days of system installation and then annually thereafter. A properly installed ASD system should reduce radon levels by 80–99%.

If levels remain above 2.0 pCi/L after mitigation, contact your mitigation contractor. Possible issues include insufficient suction, improperly sealed entry points, or a fan malfunction. Most reputable contractors offer a warranty on their work and will return to troubleshoot at no additional cost.

Step 7: Maintain the System

Radon mitigation systems require minimal maintenance but should be inspected annually. Check the manometer to ensure the fan is running. Listen for unusual noises from the fan, which could indicate wear or obstruction. Clear debris from the exhaust vent, especially after monsoon season when dust and pollen can accumulate.

Replace the fan every 5–10 years, depending on usage and manufacturer recommendations. Most fans last 10–15 years, but in Tucson’s hot, dry climate with frequent temperature swings, lifespan may be reduced. Keep records of all maintenance and testing results—this documentation is valuable if you sell your home.

Best Practices

Test Every Home, Even New Builds

Many Tucson homeowners assume that newer homes are radon-free because they are built with modern materials and sealing techniques. However, radon entry is not related to construction quality—it’s driven by geology. Even homes built in the last five years in areas like Oro Valley, Marana, or Sahuarita have tested above the EPA action level. Testing is the only way to know for sure.

Test Before Buying or Selling a Home

In Tucson’s competitive real estate market, radon testing should be a standard part of the home inspection process. Buyers should request a radon test as part of their contingency period. Sellers should consider testing proactively and addressing high levels before listing—this can reduce negotiation leverage and increase buyer confidence.

Seal Cracks, But Don’t Rely on Sealing Alone

While sealing foundation cracks and gaps is a helpful supplementary step, it is not a substitute for active mitigation. Radon can find new pathways if one is sealed, and sealing alone rarely reduces levels below 4.0 pCi/L. Use sealants (such as polyurethane caulk or hydraulic cement) to reduce airflow, but always pair sealing with a depressurization system for reliable results.

Improve Ventilation Strategically

Increasing general ventilation—such as opening windows or running exhaust fans—can temporarily lower radon levels, but it is not a sustainable solution. In Tucson’s extreme heat, keeping windows open year-round is impractical and energy-intensive. Instead, consider installing a heat recovery ventilator (HRV) or energy recovery ventilator (ERV). These systems exchange indoor and outdoor air while retaining temperature and humidity control, improving air quality and reducing radon without increasing utility bills.

Consider Radon-Resistant New Construction (RRNC)

If you’re building a new home in Tucson, incorporate radon-resistant features during construction. RRNC includes:

• A gas-permeable layer (gravel) beneath the slab
• A plastic sheeting barrier over the gravel
• A sealed and capped vertical vent pipe running from the gravel layer to the attic
• Electrical junction boxes for future fan installation

These features cost only $350–$500 to install during construction but can save $1,200–$2,500 later if mitigation is needed. Many Tucson builders now offer RRNC as a standard or optional upgrade—ask for it.

Monitor Water Sources

While most radon in Tucson homes enters through the soil, well water can also contribute, especially in rural areas. If you rely on a private well, test your water for radon using a certified lab. If levels exceed 4,000 pCi/L, consider installing an aeration system or granular activated carbon (GAC) filter. Public water supplies in Tucson are treated and monitored and are not a significant radon source.

Work with Certified Professionals

Only hire radon professionals certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB). These certifications ensure adherence to EPA and state guidelines. In Arizona, the Department of Health Services maintains a list of certified contractors. Verify credentials before signing any contract.

Tools and Resources

Radon Test Kits

Reliable, low-cost test kits are available through:

• Arizona Department of Health Services – Offers discounted test kits to residents
• Amazon – Look for kits certified by the National Radon Safety Board
• Home Depot and Lowe’s – Carry short-term charcoal kits

Ensure the kit is EPA-listed and includes lab analysis. Avoid unbranded or no-name kits—accuracy is critical.

Continuous Radon Monitors

For real-time data and professional-grade results, consider devices such as:

• Airthings View Plus – Wi-Fi-enabled monitor with historical tracking
• RadonEye Pro – Used by professionals for real-time readings
• Corentium Home by Airthings – Affordable, accurate, and easy to use

These devices are ideal for monitoring seasonal trends and verifying mitigation performance.

Sealants and Materials

For sealing foundation cracks and gaps:

• RadonSeal – Penetrating concrete sealer that reduces permeability
• SikaFlex-221 – High-performance polyurethane caulk for gaps
• Hydraulic Cement – For sealing large cracks in foundation walls

Always use products labeled for radon mitigation or sub-slab sealing. Avoid standard silicone or acrylic sealants—they are not durable enough for long-term radon control.

Professional Resources

• EPA Radon Website – www.epa.gov/radon – Comprehensive guidelines, maps, and educational materials
• Arizona Department of Health Services – Radon Program – Provides local data, contractor lists, and educational workshops
• National Radon Proficiency Program (NRPP) – www.nrpp.info – Search for certified professionals
• National Radon Safety Board (NRSB) – www.nrsb.org – Certification and training resources

Financial Assistance

While there is no state-funded radon mitigation program in Arizona, some Tucson-based nonprofits and community health organizations offer grants or low-interest loans for low-income households. Contact the Pima County Health Department or local housing authorities to inquire about available programs. Additionally, radon mitigation may be eligible for tax deductions if it’s part of a home improvement project for a rental property.

Real Examples

Case Study 1: Single-Story Home in East Tucson

A homeowner in the Catalina Foothills area tested their 1,800-square-foot slab-on-grade home and found radon levels at 8.2 pCi/L. The home had no basement but featured a crawl space under the garage. A professional contractor installed a sub-slab depressurization system with a 4-inch PVC pipe, an in-line fan in the attic, and sealed all visible cracks. Post-mitigation testing showed levels dropped to 0.7 pCi/L. The homeowner reported improved respiratory health and increased peace of mind.

Case Study 2: Ranch-Style Home in Sahuarita

A family in Sahuarita purchased a 1980s home with a concrete block foundation. Initial testing revealed 6.5 pCi/L. The mitigation specialist discovered that radon was entering through unsealed block joints and a gap around the main sewer line. The solution involved sealing the block walls with RadonSeal, installing a sub-slab system with dual suction points, and adding a vent to the attic. Levels fell to 1.1 pCi/L. The family later sold the home for 7% above market value, citing radon mitigation as a key selling point.

Case Study 3: New Construction in Oro Valley

A builder in Oro Valley incorporated RRNC into a new development of 40 homes. Each home included a gravel layer, vapor barrier, and pre-installed vent pipe. All homes were tested after construction, and average radon levels were 0.9 pCi/L—well below the EPA action level. Buyers appreciated the proactive safety measure, and the builder received recognition from the Arizona Home Builders Association for health-conscious design.

Case Study 4: Rental Property in Downtown Tucson

A landlord tested a 1950s duplex and found radon levels at 5.3 pCi/L. After installing a sub-slab system, levels dropped to 1.4 pCi/L. The landlord provided tenants with a copy of the test results and maintenance records. Tenants reported fewer headaches and improved sleep quality. The property’s occupancy rate increased by 15% within a year.

FAQs

Is radon a serious problem in Tucson?

Yes. While Tucson is classified as a moderate-risk zone, localized areas—particularly those near igneous rock formations or alluvial fans—can have high radon levels. Many homes in the city and surrounding communities have tested above the EPA action level. Radon is invisible and odorless, so testing is the only way to know your risk.

Can I test for radon myself?

Yes. Short-term and long-term test kits are easy to use and widely available. However, for real estate transactions or if levels are borderline, a professional test with a continuous monitor is recommended for accuracy.

How much does radon mitigation cost in Tucson?

Typical installation costs range from $1,200 to $2,500, depending on home size, foundation type, and system complexity. Sub-slab systems are generally the most cost-effective. Prices may be higher in homes requiring additional sealing or multiple suction points.

How long does a radon mitigation system last?

The fan typically lasts 10–15 years, and the PVC piping can last the lifetime of the home if properly installed. Regular annual checks ensure longevity.

Will radon mitigation increase my energy bills?

No. The fan consumes very little electricity—equivalent to a standard light bulb. In fact, sealing foundation cracks and improving ventilation can reduce heating and cooling losses, potentially lowering utility costs.

Does radon affect only basements?

No. Radon can enter any home, regardless of whether it has a basement. In Tucson, most homes are slab-on-grade or have crawl spaces. Radon rises from the soil and enters through the lowest level, which could be the ground floor.

Can I mitigate radon myself?

Technically yes, but it is not recommended. Radon mitigation requires precise engineering to create negative pressure beneath the foundation. DIY systems often fail due to improper sealing, incorrect fan sizing, or poor vent placement. Professional installation ensures effectiveness and safety.

How often should I retest after mitigation?

Test again within 30 days of installation to confirm effectiveness. Then, test every two years—or annually if you have a history of high levels. Retest after major renovations or if you change your HVAC system.

Is radon covered by home insurance?

No. Radon testing and mitigation are considered preventive health measures and are not covered by standard homeowners’ insurance policies. However, mitigation costs may be deductible as a home improvement for rental properties.

Can plants or air purifiers reduce radon?

No. Neither houseplants nor HEPA air purifiers remove radon gas. Radon is a radioactive gas, not a particle or chemical pollutant. Only active soil depressurization effectively reduces indoor radon concentrations.

Conclusion

Reducing radon in Tucson homes is not an optional safety measure—it is a necessary step to protect the long-term health of your family. With its unique geology and climate, Tucson presents specific challenges and opportunities for radon mitigation. The good news is that radon is one of the most preventable environmental health risks in the home. With accurate testing, proper system design, and professional installation, radon levels can be reduced to safe, even negligible, concentrations.

Every home in Tucson should be tested. Every home with elevated levels should be mitigated. And every new home should be built with radon-resistant features. The cost of testing is minimal compared to the cost of untreated exposure. The effort required is small compared to the peace of mind it brings.

Take the first step today: order a radon test kit. Place it in the lowest livable area of your home. Follow the instructions. Send it in. Know your numbers. Then, if needed, take action. Your health—and the health of those you love—depends on it.