If you live in Massachusetts and you've never tested your home for radon, you may be taking a bigger risk than you realize. Radon is the second leading cause of lung cancer in the United States – responsible for an estimated 21,000 deaths every year according to the EPA – and Massachusetts is not immune. In fact, many areas across the state have radon levels that exceed safe thresholds, often without homeowners ever knowing.

So, are radon levels high in Massachusetts? The short answer is yes, making radon testing and mitigation necessary investments for home and business owners to invest in.

What Radon Levels Are Considered High?

Before diving into Massachusetts-specific data, it helps to understand how radon levels are measured and evaluated. Radon concentration is measured in picocuries per liter of air (pCi/L). The EPA recommends taking action if your home tests at or above 4 pCi/L, and strongly encourages mitigation for readings between 2 and 4 pCi/L. The national average indoor radon level is approximately 1.3 pCi/L, but many Massachusetts homes test well above that baseline.

What the Data Shows About Massachusetts

Massachusetts is classified by the EPA as having significantly high radon levels across much of the state. The EPA divides counties into three zones based on predicted average indoor radon levels:

  • Zone 1: Greater than 4 pCi/L (highest potential)
  • Zone 2: Between 2 and 4 pCi/L (moderate potential)
  • Zone 3: Less than 2 pCi/L (low potential)

Several Massachusetts counties fall into Zone 1 - meaning homes in those areas are statistically more likely to have elevated radon levels that require immediate action. Many others fall into Zone 2, which still presents a meaningful health risk that homeowners should not ignore.

The Massachusetts Department of Public Health has consistently found through testing programs that a significant percentage of homes across the state test above the EPA action level. Studies suggest that roughly one in three Massachusetts homes may have elevated radon levels – a statistic that should concern every homeowner in the state.

Why Is Massachusetts at Risk?

The elevated radon potential in Massachusetts is not a coincidence. Several geological and structural factors combine to make the state particularly susceptible.

1. Granite & Uranium-Rich Bedrock

Much of Massachusetts sits on or near granite bedrock, which naturally contains higher concentrations of uranium. As uranium slowly breaks down over thousands of years, it produces radium – and radium decays into radon gas. The geology of New England essentially creates a natural radon factory beneath our homes.

Communities in the Greater Boston area, including Canton, Milton, Needham, Westwood, Brookline, Newton, Dover, Medfield, and Wellesley, all sit within geological zones where uranium-containing rock formations are prevalent. This doesn't mean every home will test high, but it does mean the underlying risk is present throughout the region.

2. Glacial Till & Permeable Soil

In addition to bedrock, Massachusetts soils are largely the product of glacial activity from the last ice age. This glacial till tends to be permeable, allowing radon gas to migrate easily from the soil into surrounding structures. The more permeable the soil, the more efficiently radon travels – and the more readily it finds its way through cracks and gaps in your foundation.

3. Cold Climate & Tight Home Construction

As discussed in the context of seasonal radon fluctuations, Massachusetts winters are long, cold, and demand that homes remain tightly sealed for months at a time. This dramatically reduces natural ventilation, allowing radon to accumulate to dangerous concentrations indoors. Older homes throughout the region often have stone foundations, fieldstone basements, or older poured concrete with natural cracks and gaps – all of which serve as convenient entry points for radon gas.

4. Older Housing Stock

Massachusetts has one of the oldest housing stocks in the nation. Older homes were not built with radon in mind, and many lack the vapor barriers, sealed foundations, and sub-slab construction techniques that modern building codes encourage. This means a significant portion of homes across the state are structurally predisposed to higher radon infiltration.

What Are the Higher-Risk Areas Within Massachusetts, in Terms of Radon?

While radon can be found in elevated concentrations anywhere in Massachusetts, certain areas and communities tend to see more consistent elevated readings. Towns and neighborhoods situated near granite formations, in river valleys, or with older housing tend to report higher average test results.

In the Greater Boston suburbs – including communities like Canton, Westwood, Milton, Needham, Brookline, Newton, Dover, Medfield, and Wellesley – radon testing has revealed elevated levels in a notable portion of tested homes. This is not a scare tactic. It is simply a reflection of the geology and housing stock that define this region.

The important takeaway is that no neighborhood is automatically safe, and no home should be assumed to have acceptable radon levels without proper testing.

What Can Massachusetts Homeowners Do To Reduce Radon Risks?

The good news is that elevated radon levels are entirely fixable. A professionally installed radon mitigation system can reduce indoor radon levels by up to 99%, bringing even the highest readings well below the EPA action level. These systems are reliable, low-maintenance, and – when installed correctly – highly effective.

Step 1: Test Your Home

If you have never tested your home for radon, start there. Both short-term (48-hour) and long-term (90-day) tests are available. Long-term tests provide the most accurate picture of your home's average radon exposure.

Step 2: Understand Your Results

  • Below 2 pCi/L: Continue monitoring periodically
  • 2–4 pCi/L: Strongly consider mitigation
  • Above 4 pCi/L: Take action as soon as possible

Step 3: Work With a Certified Mitigation Professional

Not all radon contractors are equal. Look for NRPP-certified professionals with a proven track record and direct owner involvement in the work.

Trust Bird Dog Specialty Contracting

At Bird Dog Specialty Contracting, we've built our reputation on delivering expert radon mitigation services to homeowners throughout the Greater Boston area. With over 30 years of construction and industry experience, our NRPP-certified team brings unmatched knowledge and craftsmanship to every project. We serve Canton, Westwood, Milton, Needham, Brookline, Newton, Dover, Medfield, Wellesley, and surrounding communities.

We believe that every Massachusetts homeowner deserves a safe home – and we're committed to making that happen with professional installations, transparent communication, and same-day fan replacement services when needed.

Don't assume your home is safe. In Massachusetts, the risk is real – and testing is the only way to know for sure. Reach out today.