Radon Testing in Maryland: What Levels Mean and When You Should Mitigate

Radon is one of those issues that people tend to overlook until they are in the process of buying a home, selling a home, finishing a basement, or trying to make their rental safe. It is invisible, odorless, and impossible to detect without testing.

This is why radon testing is such an important part of the home inspection process. Radon testing is the simplest solution for homeowners, buyers, sellers, and landlords in Baltimore City, Baltimore County, and the surrounding Maryland area looking to obtain reliable information on indoor air quality in a home before an issue becomes bigger.

If you are looking to request professional testing, you can do so here: Radon testing.

Quick answer

Radon is a naturally-occurring radioactive gas that can seep into the home from underground sources. The Maryland Department of Health notes radon “is invisible and odorless and can only be detected by special testing equipment.” Furthermore, the Maryland Department of Health warns that radon “is the leading cause of lung cancer among nonsmokers.” Maryland Department of Health radon page

The EPA recommends fixing a home with a radon level of 4 pCi/L or higher. The EPA also recommends considering repairs when the level is between 2 and 4 pCi/L because “there is no truly safe level of radon exposure.” EPA radon action level

The only way to know your radon level is to test. Radon levels vary from home to home, and even within different areas of the same home. The EPA recommends using a map to understand general trends in your area, but the EPA notes “these maps should not be used to determine whether a home should be tested for radon.” EPA Map of Radon Zones

What radon is in plain English

Radon is a gas that forms naturally from uranium underground, and it can enter homes from below through cracks in the home’s foundation, drains, sump openings, and other sources. The issue with radon is that it tends to accumulate in buildings most, such as basements and first floors.

This is why you should consider radon testing for:

Finished basements
Basement bedrooms
Crawlspaces
Sump pits
Foundation cracks
New energy efficient windows and doors
Real estate transactions
Older homes that have not been tested

A home may look nice on the surface, but it will not be able to protect you and your family from radon exposure.

What the pCi/L means

Radon levels in picocuries per liter (pCi/L) can be confusing to understand.

The most important number to remember is the EPA’s action level for radon. According to the EPA, an action level is the point at which they recommend that you begin to take steps to reduce the radon in your home. The EPA’s action level is 4 pCi/L. The EPA also recommends considering repairs when the level is between 2 and 4 pCi/L, since there is no truly safe level of radon exposure. EPA radon action level

The simplest way to understand what the number means is demonstrated below:

Radon Level	What it means
Less than 2 pCi/L	Low level but not zero
2 to 3.999 pCi/L	Consider mitigation
4 pCi/L or greater	Mitigation recommended

Why Maryland homes should be tested

Every home in Maryland is different, so the best way to understand your risks is to test your home.

EPA Map of Radon Zones was designed to demonstrate general trends of radon levels across the country, but the EPA warns “these maps should not be used to determine whether a home should be tested for radon.”

This is an especially crucial consideration for people shopping or settling in Baltimore City, Baltimore County, and similar regions with a wide variety of housing options. Every home and building in the area is different, which means that their radon levels are different as well. The most prudent course of action is to test the home or building in question to obtain reliable information.

When should you test for radon

Radon testing is important to do in a number of different situations.

When buying a home

This is one of the best times to conduct a radon test, since the information you receive can help you make an informed decision before entering a contract. The EPA has a Home Buyers and Sellers Guide to Radon, and the 2024 edition specifically addresses the importance of conducting radon tests and understanding the results throughout the real estate transaction process.

When you are a buyer, a radon test can help give you reliable information on a property before you inherit its problems.

When selling a home

People who are selling their home may want to conduct a radon test to demonstrate that the property is safe and to make it easier to sell. This can be a wise move, since radon levels are often a concern for buyers with basements or first-floor units.

A radon test can provide potential buyers with reliable information on the level, especially if the seller addresses any issues that are discovered.

When you own a rental property

While radon testing is separate from most local Baltimore City and Baltimore County rental inspection processes, it can also be a prudent move for landlords who want to ensure the wellbeing of their tenants.

Landlords in Baltimore City and Baltimore County can rely on radon testing as a way to go above and beyond the standard minimum requirements when it comes to their rental properties. Testing is especially important when there are finished basements, lower-level bedrooms, and long-term rentals.

For more information on local rental preparation, you can review the following links: Baltimore City Rental License Inspection Checklist and Baltimore County Rental Inspection Sheet Explained.

After renovations

Renovations can impact radon levels if they involve opening new pathways for the gas, such as finishing a basement or first floor or making a home more energy efficient.

If you have not tested before

If you have not tested your home or building before, you should do so now. It is impossible to determine whether there is a problem if you do not test.

What happens during a professional radon test

A professional radon test is typically an easy process for the homeowner or building occupant. A radon inspection service will place devices in the appropriate area and wait for them to collect the necessary data for analysis.

A Home Sweet Home Inspection’s radon testing service page notes that they offer continuous radon monitors that meet EPA standards and provide reliable results for radon testing in Baltimore and the surrounding area.

Before the test, it is important to ensure that occupants follow all recommended guidelines, such as keeping windows and exterior doors closed when necessary and keeping the device undisturbed. The goal is to ensure that the device collects reliable data on the indoor air quality of the home or building.

What affects radon levels

Radon levels tend to fluctuate from day to day and time to time. The EPA notes that it is impacted by a number of different environmental factors, but the most important is how much time has passed since the last significant weather event. Other factors can include the home’s tendency to let in fresh air underground, the type of foundation, and more.

This does not mean that radon testing is unreliable.

It means that testing should be done correctly to account for these variables, and the resulting data should be interpreted correctly.

Some of the most common factors include:

Weather
Ventilation
Foundation cracks
Sump pits
Crawlspace conditions
Basement finishing
Heating and cooling
Closed house conditions

If the radon level is high, it is time to hire a radon mitigation professional.

When should you mitigate

Radon mitigation refers to the process of reducing the amount of radon that is present in a home or building. The EPA recommends mitigating when the radon level is 4 pCi/L or above.

The EPA warns that radon levels below 4 pCi/L still pose a risk, however, and most homes can be mitigated to bring the level below 4 pCi/L. EPA radon action level

The practical guide below can be used to understand what the radon testing results mean.

Test Outcome	Recommended Course of Action	Comments
Level 4 pCi/L or greater	Mitigation recommended	Radon mitigation can reduce the amount of radon in the home.
Level between 2 and 4 pCi/L	Consider mitigation	The decision to mitigate should be based on a number of factors, including the value of the home.
Level below 2 pCi/L	Store results and consider re-testing in the future	Mitigation is typically unnecessary unless conditions change significantly.

Radon mitigation is a responsible choice for any homeowner or landlord with a radon level of 4 pCi/L or higher.

What does mitigation usually involve

Radon mitigation is typically a process that involves installing a system to reduce the amount of radon that enters the home or building.

The most appropriate radon mitigation method will vary based on the foundation, basement, crawlspace, slab, sump, and other factors involved. The EPA has consumer resources to help you understand the options available for radon mitigation in your home, such as the EPA Consumer Guide to Radon Reduction. After mitigation, it is important to re-test to confirm the radon level.

Radon testing versus a standard home inspection

A home inspection and a radon test are two completely different services.

A standard home inspection is conducted to obtain an overview of the general condition of a home’s systems and components. A radon test, on the other hand, is conducted to determine the amount of radon gas in a home.

This is why a house can have a great home inspection and still need a radon test, since the inspector will not be able to see or smell the radon gas. For more information on home inspection services, you can review the following links: Home inspection and Services page.

Radon and Baltimore rentals

As a landlord, radon is a concern that should be addressed as part of a larger safety initiative. While Baltimore City rental license inspections and Baltimore County rental registration inspections typically focus on the City or County specific checklist, radon testing can be an important step for any landlord who wants to ensure the wellbeing of their tenants.

When preparing a packet for Baltimore City or Baltimore County rental license inspections, it is important to keep the following documents together:

Rental inspection form
Lead certificate, when applicable
Radon test, if applicable
Repair receipts
Tenant records
Registration confirmation

If your rental was built before 1978, you may also want to review the following article: Maryland Lead Paint Rules for Rentals.

Common mistakes people make with radon

Newer homes are not affected

Newer homes are still impacted by the same environmental factors that contribute to radon levels in older homes.

Finishing a basement eliminates the risk

A finished basement typically increases the risk since people spend more time in the lower level.

Radon maps are reliable indicators

As mentioned previously, the EPA specifically warns against using radon maps to determine whether a specific home should be tested for radon gas. Test the building itself instead. EPA Map of Radon Zones

Radon testing is not scheduled in time

Radon testing requires time to complete and analyze. If you are in the middle of a real estate transaction, you should schedule the test early enough that the results can be reviewed before finalizing an agreement.

Mitigation means the deal is off

Radon mitigation is a common issue in real estate transactions, so it is a familiar concept for buyers, sellers, agents, and inspectors. The information provided by a radon test is an important factor to consider, but it should not derail the entire process. Instead, the involved parties should work together to obtain reliable information on the radon level and find a mitigation professional if necessary.

A simple radon testing checklist

Use this as a reference guide before scheduling a radon test:

Determine your reasons for testing, such as buyer inspection, seller preparation, rental safety, or another purpose
Choose a professional radon test if you need reliable documentation
Follow closed house conditions and other guidelines
Avoid moving or disturbing the device
Review the test results in terms of pCi/L
Mitigate if the result is 4 pCi/L or greater
Consider mitigation if the result is between 2 and 4 pCi/L
Store the results with the applicable documents
Re-test if mitigation or renovations take place

FAQs

What radon level is considered high?

The EPA recommends mitigating when the level is 4 pCi/L or greater. The EPA also recommends considering mitigation when the level is between 2 and 4 pCi/L because there is no truly safe level of radon exposure. EPA radon action level

Can I smell or see radon?

No, since the Maryland Department of Health warns that radon “is invisible and odorless and can only be detected by special testing equipment.” Maryland Department of Health radon page

Should every Maryland home be tested?

Yes, testing is the most responsible way to address radon gas. The EPA specifically warns that radon maps should not be used to determine if a specific home should be tested, since every property can have different levels. EPA Map of Radon Zones

Is radon testing part of a home inspection?

Radon testing is a separate service from a home inspection. The two services provide incredibly different sets of information on a home.

Should landlords test rentals for radon?

Testing a rental for radon can be a wise decision for any landlord, since it can reduce risk in a number of different ways. Radon testing is usually independent from most local Baltimore City or Baltimore County rental inspection processes.

What happens if the result is high?

If the radon level is 4 pCi/L or greater, the EPA recommends mitigating to reduce the amount of radon gas in the home. A qualified radon mitigation contractor can recommend the most appropriate course of action. EPA Consumer Guide to Radon Reduction

Ready to schedule radon testing in Maryland

Radon is one of those issues that can impact nearly every home, but it is invisible, odorless, and impossible to detect without testing. If you are a buyer, seller, landlord, or owner looking to get reliable information on a home’s radon level, A Home Sweet Home Inspection can help you conduct a professional radon test in Baltimore City or Baltimore County.

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To book your test, you can contact us here: Schedule an inspection.