Radon in Norfolk County, MA: Testing and Mitigation Cost

EPA's 1993 Map of Radon Zones rates Norfolk County, south and west of Boston, Zone 2: a predicted county average indoor screening level of 2 to 4 pCi/L. Neighboring Middlesex County is one of the 3 Massachusetts counties EPA rates Zone 1.

Of the 40 ZIP areas the Census Bureau relationship file maps to Norfolk County, 37 lie in Zone 2 counties only, 2 also take in Zone 3 land and 1 spans counties in all three zones, by our count against EPA's file. MDPH says buildings with high radon are found in every county in the Commonwealth (MDPH).

A standard sub-slab system runs $1,200 to $2,000 installed in HomeGuide's Feb 2026 survey, and the county's older colonials with stone foundations often need more.

Licensing and permits

Certification: Massachusetts does not certify radon professionals; MDPH recommends a mitigator certified by NRPP or NRSB and posts a monthly list of nationally certified mitigation professionals.

HIC registration: contractors working on owner-occupied one-to-four-unit homes must register as Home Improvement Contractors under M.G.L. c. 142A, and jobs estimated at $1,000 or more require a written contract (Massachusetts Office of Consumer Affairs).

Town building departments in Quincy, Brookline, Needham and the rest set permit rules; HomeGuide puts radon permits at $25 to $150 where required.

Ask for the post-mitigation test in writing.

Local conditions

Much of the county rests on granite and related crystalline rock: the Dedham granite under the western towns and the Quincy granite of the Blue Hills, which rise between Milton, Quincy and Canton. Granite can carry uranium, and where it is fractured or covered by thin glacial till, soil gas finds a path into basements.

The Boston Basin's slate and conglomerate underlie the northeastern towns near Brookline and Quincy, and sandy glacial deposits fill the valleys along the Neponset and Charles rivers.

Housing is old and varied: early colonials with fieldstone cellars, capes on block from the interwar and postwar decades, and newer homes with poured basements along I-95 and Route 128.

Ledge is a familiar word to anyone who has dug a foundation in Quincy, Milton or Dedham. Where granite sits a few feet below the slab, there may be little gravel for a fan to pull through, so a mitigator may drill test holes and measure suction before choosing how many points to use.

Brookline and the inner towns also have two-family and triple-decker housing; a system there has to cover a shared basement, and the owner of the building, not each tenant, usually arranges it.

What drives local prices

Fieldstone and block foundations in older homes in the county can need sealing or block-wall suction, $1,800 to $3,000 based on HomeGuide's published survey, against $1,200 to $2,000 for a poured basement.
Ledge: shallow granite under some lots can limit how air moves under the slab, which may add a suction point (est. $250 to $500 in our calculator).
Finished basements and interior pipe routes: an est. ×1.15.
Permit $25 to $150 and professional retest $125 to $400 (HomeGuide).
Larger homes in Wellesley, Needham and Westwood: an est. ×1.25 at 2,500 sq ft or more.

Common jobs

Sub-slab systems in capes and colonials with poured basements.
Sealing and suction in fieldstone cellars.
Systems routed through garages to keep pipes off the front of the house.
Inspection-period tests in a busy resale market.

From test to fixed, and where we cover

Step 1: test the lowest lived-in level with the house closed. Step 2: at 4 pCi/L or more, get two bids from nationally certified, HIC-registered mitigators.

Step 3: compare them with the calculator. Step 4: retest after installation.

We cover Quincy, Brookline, Dedham, Needham, Wellesley, Braintree, Milton, Norwood, Walpole, Franklin and Weymouth, along I-93, I-95 and Route 128.

Communities: Quincy, Brookline, Dedham, Needham, Wellesley, Braintree, Milton, Norwood, Walpole, Franklin, Weymouth

Before you sign

There is time to collect two written bids (EPA Citizen's Guide). For a job of $1,000 or more, Massachusetts requires a written contract from a registered contractor.

Questions about Norfolk County

Is Norfolk County high in radon?

EPA rates it Zone 2, but MDPH reports high-radon buildings in every Massachusetts county. Test to know.

Why does granite matter for radon?

Granite can carry uranium, which decays to radon; fractured rock and thin soils let the gas reach basements.

Does my mitigator need a Massachusetts license?

No state radon license exists; MDPH recommends NRPP or NRSB certification, and HIC registration applies under M.G.L. c. 142A.

What does mitigation cost in Norfolk County?

HomeGuide's national range is $1,200 to $2,000 for a sub-slab system; older stone foundations can cost more.

Sources

Nearby counties

Radon on Cape Cod (Barnstable County, MA)

Rules and fees change; confirm with the state radon office. Price your own system with the radon mitigation cost calculator, read the radon mitigation cost guide, or check any ZIP with the radon levels by ZIP tool.