Quick Summary

Millions of renters across Canada & United States live in apartments, basement suites, condos, and multi-unit properties every year. Yet, very few know whether their homes have ever been tested for radon. Because radon is invisible, odorless, and naturally occurring, tenants often have no way of knowing they may be exposed to elevated levels for months or even years.

For landlords, growing awareness around indoor air quality is also raising important questions around testing responsibilities, disclosure expectations, tenant safety, and long-term property protection. Whether you manage a single rental home or multiple properties, or whether you are a tenant trying to understand indoor air quality risks better, radon awareness is becoming an increasingly important part of modern housing safety conversations.

As discussions around healthier homes and continuous indoor air monitoring continue to grow, radon testing in rental units is no longer viewed as a niche issue. It is increasingly becoming part of broader conversations around tenant wellness, smart property management, and proactive indoor air quality monitoring.

Quick Answer: Should Rental Units Be Tested for Radon?

Yes. Radon can accumulate in rental homes, apartments, condos, and basement suites just like owner-occupied properties.

Testing is especially important for:

• Ground-floor apartments

• Basement rental units

• Older buildings with foundation cracks

• Properties located in higher radon regions across Canada and the United States

Health Canada recommends taking action when long-term radon levels exceed 200 Bq/m3, while the U.S. EPA recommends mitigation at 4.0 pCi/L. Both agencies agree that long-term exposure to elevated radon levels can significantly increase the risk of lung cancer.

Proactive radon testing helps support:

• Tenant health and indoor air quality

• Landlord liability protection

• Long-term property value

• Safer living environments

Continuous radon monitoring can also provide more accurate long-term insights than one-time short-term tests.

Why Radon in Rental Units Deserves Serious Attention

Radon is the leading cause of non-smoking lung cancer in the United States and Canada. According to the EPA, approximately 1 in 15 U.S. homes has elevated radon levels at or above the recommended action level of 4 pCi/L. Elevated radon has been found in buildings across all 50 states.

Health Canada states that roughly 1 in 5 (or ~18%) of Canadian homes have elevated radon levels measuring at or above the national action guideline of 200  Bq/m3. Once trapped indoors, radon can accumulate over time, increasing your long-term health risks.

Rental properties deserve particular attention because many tenants spend substantial amounts of time indoors, especially in basement suites, lower-level apartments, and ground-floor units where radon concentrations are often highest. 

Growing awareness around indoor air quality, healthy homes, and long-term environmental exposure has also encouraged more landlords and tenants to pay closer attention to hidden air quality risks inside residential buildings. 

Do Landlords Have to Test for Radon?

One of the most common questions around rental property radon inspection is whether landlords are legally required to test for radon.

The answer depends heavily on state and local laws.

What About Radon Laws in Canada?

Canada currently does not have a nationwide law requiring landlords to test rental properties for radon. However, Health Canada strongly recommends testing all homes and rental units below the third floor, especially during colder months when buildings remain closed for longer periods.

Public awareness around radon exposure in rental housing has continued growing in recent years, particularly following increased media coverage and public health discussions surrounding indoor air quality.

Some housing advocates, property professionals, and public health organizations have also called for stronger testing and disclosure requirements in Canadian rental properties. Discussions around mandatory testing have gained additional attention following reports such as CBC News’ coverage of Nova Scotia landlords advocating for mandatory radon testing in rental housing.

Although regulations vary by province and municipality, proactive testing is increasingly viewed as:

• A responsible property management practice

• A tenant safety measure

• A long-term indoor air quality strategy

• A way to support transparency between landlords and renters

Radon Disclosure Laws for Rental Properties in the United States 

As of 2025, several US states have adopted laws specifically addressing radon in rental housing.

Colorado, USA

Colorado landlords must:

• Provide written radon disclosures before lease signing

• Share any known radon information about the property

• Provide tenants with a state radon information brochure

• Obtain a signed acknowledgment from tenants

Colorado strengthened these requirements through Senate Bill 23-206, which took effect in 2023.

Florida, USA

Florida requires landlords to include a radon warning statement in residential rental agreements lasting longer than 45 days.

The disclosure explains:

• Radon is a naturally occurring radioactive gas

• Elevated levels may present health risks

• Tenants can contact local health departments for information

Illinois, USA

Illinois has one of the most tenant-focused radon laws in the country.

Landlords must provide:

• The state’s “Radon Guide for Tenants.”

• Copies of existing radon test reports

• A disclosure form regarding known radon hazards

Tenants may also conduct radon testing within 90 days of moving in.

Maine, USA

Maine requires:

• Testing in many new rental properties

• Additional testing when requested by tenants under certain conditions

• Written disclosure of radon results and mitigation history

Local Ordinances Continue Expanding

Some counties and municipalities now have additional radon requirements beyond state laws. For example, Montgomery County, Maryland, requires landlords to:

• Test rental units for radon

• Share results with tenants

• Mitigate levels at or above 4.0 pCi/L

Because local regulations continue evolving, landlords should regularly review both state and municipal requirements.

Tenant Rights for Radon Testing: What Renters Should Know

Even in states without formal disclosure laws, tenants still have several practical options.

Ask Questions Before Signing a Lease

Before moving in, tenants should ask:

• Has the property been tested for radon?

• When was the last test performed?

• What were the results?

• Has mitigation ever been installed?

A landlord’s willingness to discuss indoor air quality often says a lot about how the property is managed overall.

Request a Radon Test

In some states, tenants have the legal right to request testing. Even where no formal law exists, tenants can still submit written requests for radon testing, particularly for basement or ground-floor units.

Conduct Independent Testing

Many renters choose to test independently using:

• Short-term radon test kits

• Continuous radon monitors

Independent testing can provide peace of mind and help tenants better understand the air quality inside their living space.

Review Lease and Housing Safety Protections

Tenants should review lease agreements for any language related to:

• Environmental hazards

• Air quality

• Property maintenance responsibilities

If elevated radon levels are confirmed and ignored, tenants may also consider contacting:

• Local housing authorities

• Public health agencies

• Tenant advocacy organizations

Why Continuous Radon Monitoring Is Changing Rental Safety

Traditional radon tests provide only a short snapshot of indoor air quality. However, radon levels naturally fluctuate throughout the day due to:

• Weather conditions

• Seasonal changes

• Ventilation patterns

• Indoor air pressure differences

This is one reason many landlords, tenants, and property managers across Canada and the United States are beginning to move toward continuous radon monitoring rather than relying only on one-time short-term tests.

Continuous monitoring offers several advantages:

• Real-time radon visibility

• Better long-term exposure awareness

• Faster identification of unusual changes

• Easier documentation for landlords and property managers

• Ongoing verification after mitigation

Connected monitoring technology also allows users to track trends through mobile apps and cloud-based reporting systems, making long-term indoor air quality monitoring more practical and accessible.

For landlords managing multiple units or basement rental suites, continuous monitoring can support a more proactive and well-documented indoor air quality strategy over time.

Who Pays for Radon Testing?

Responsibility for radon testing costs depends on local laws and individual lease agreements.

• When Testing Is Legally Required: In states where landlords must test rental properties, testing costs generally fall to the property owner.

• When Tenants Request Testing: In other situations, testing costs may be negotiated between both parties or addressed within the lease agreement.

• Independent Tenant Testing: If tenants choose to purchase their own radon test kit or continuous monitor, the cost is usually their responsibility.

• Mitigation Costs: If elevated radon levels require mitigation, structural improvements typically become the landlord’s responsibility as part of maintaining safe living conditions.

How to Test for Radon in an Apartment or Rental

Testing for radon in a rental unit follows the same general principles as in any home, with a few specific considerations for apartment settings.

• Placement: The EPA recommends placing a radon monitor in the lowest livable area of the unit, typically a ground-floor or basement unit, for renters. Position it at least 20 inches above the floor, away from windows, vents, exterior walls, and high-humidity areas like kitchens and bathrooms. In a multi-room apartment, a central room that is regularly used as a bedroom, living room, or home office is ideal.
  

• Test Duration: Short-term charcoal canister tests run for 48 to 96 hours and provide a snapshot. They are a reasonable starting point, but because radon levels fluctuate with weather, seasons, and ventilation, they can miss peak exposure periods. A continuous radon monitor, one that updates readings every 10 minutes throughout the day, captures the full range of what you are actually breathing, including overnight peaks and seasonal changes.
  

• Closed-House Conditions: For short-term tests to be accurate, windows and doors in the unit should remain closed for at least 12 hours before and during the test period, with only normal entry and exit permitted
  

• Documentation: Keep a record of your test, including start and end dates, the result in pCi/L, and the device or kit used. Proper documentation can help support future disclosures, maintenance planning, and liability protection. 

What Happens If Radon Levels Are High in a Rental?

If testing reveals elevated radon levels above Health Canada’s guideline of 200 Bq/m3 or the EPA’s action level of 4.0 pCi/L, steps should be taken to reduce exposure.

• Notify the Property Owner: Tenants should provide written documentation of the test results and request additional evaluation or mitigation if necessary.

• Professional Mitigation: Certified radon mitigation professionals can install systems designed to safely redirect radon gas outdoors before it accumulates inside the property. Many professionally installed mitigation systems can reduce radon levels significantly when properly maintained.

• Continue Monitoring: After mitigation, continued monitoring helps confirm that the system remains effective over time and that indoor radon levels stay within recommended guidelines.

Why Proactive Testing Benefits Landlords Too

For landlords who may be wondering whether radon testing is worth the effort in states where it is not legally required, here is a straightforward answer: yes.

• Reduced Liability Risk: Documented testing and mitigation records may help reduce legal exposure if future disputes arise.

• Better Tenant Trust: Tenants increasingly value transparency around indoor air quality and environmental safety.

• Stronger Property Value: Properties with documented radon testing and mitigation history may appeal more strongly to future tenants and buyers.

• Long-Term Building Protection: Proactive monitoring supports healthier indoor environments while reinforcing responsible property management.

Simple Radon Safety Checklist for Landlords

Landlords looking to improve rental property safety can take several proactive steps:

• Test all basement and ground-contact units

• Keep organized records of radon results

• Share disclosures transparently with tenants

• Re-test after renovations or major structural changes

• Consider continuous monitoring for multi-unit properties

• Address elevated levels quickly through certified mitigation professionals

These steps not only support tenant safety but also strengthen long-term property management practices.

Ecosense’s smart radon monitoring solutions, including EcoQube, EcoQube Flex, EcoBlu, and RadonEye, are designed to support continuous monitoring across apartments, rental homes, and multi-unit properties. Their connected monitoring technology allows landlords and tenants to track indoor radon levels more consistently while supporting informed long-term air quality decisions. 

Final Thoughts

Radon testing in rental properties is becoming an increasingly important part of modern housing safety conversations across Canada and the United States.

For tenants, understanding radon risks and testing options provides greater awareness of indoor air quality and long-term health considerations. For landlords and property managers, proactive testing and transparent communication can support safer living environments, stronger tenant trust, and reduced long-term liability concerns.

As smart home technology and continuous monitoring solutions continue evolving, radon awareness is likely to become a more common expectation within rental housing markets throughout North America.

Because when it comes to indoor air quality, what cannot be seen should never be ignored.

FAQs

Q. Can radon levels change throughout the year in a rental unit?

Yes. Radon levels naturally fluctuate due to weather conditions, temperature changes, ventilation patterns, and seasonal shifts. A rental unit that tests low during one season may show higher readings during another. This is why long-term or continuous radon monitoring often provides a more accurate understanding of indoor air quality over time.

Q. Is radon only a concern in older apartment buildings?

No. Radon can affect both older and newer buildings. Because radon enters from the soil beneath a structure, factors such as foundation type, building design, ventilation, and construction methods often have a greater impact than the age of the property itself.

Q. Can opening windows reduce radon levels temporarily?

Yes, improving ventilation may temporarily lower indoor radon concentrations. However, opening windows is not considered a reliable long-term solution. If elevated radon levels are confirmed, professional radon mitigation is typically the most effective way to reduce exposure consistently.

Q. Why are continuous radon monitors becoming more popular in rental housing?

Continuous radon monitors provide real-time readings instead of a single short-term snapshot. This allows landlords, tenants, and property managers to better understand how radon levels change throughout the day and across different seasons while helping verify whether mitigation systems are working properly over time.

Q. Should tenants ask about radon testing before signing a lease?

Yes, especially for basement apartments, lower-level suites, and ground-floor rental units. Asking whether the property has previously been tested for radon can help tenants make more informed decisions about indoor air quality and long-term living conditions before moving in.