Concord radon mitigation — local context
Straight answer: Concord sits in Merrimack County, which the U.S. EPA maps as Radon Zone 2 (moderate potential), not the highest-risk Zone 1 — so the "high-radon area" label you'll read elsewhere isn't accurate here. The catch: Air Chek test data compiled at county-radon.info puts the county's average indoor reading at 5.2 pCi/L, above EPA's 4.0 action level, so test every home regardless of zone. There's good reason locally — the bedrock under the city is the USGS-named "Concord Granite," a two-mica granite whose type locality is the city itself (the same stone quarried on Rattlesnake Hill for the State House). Uranium decay in that granite drives NH's radon, in air and in private wells. We handle both, including radon mitigation and follow-up radon level testing. Radon mitigation runs $900–$6,000 (most jobs $1,950–$2,250); the radon test is $50, credited toward the job if you proceed. NH radon cert RMS-113966.
Frequently asked questions
Is Concord, NH actually a high-radon area?
Not by EPA's classification. Concord is in Merrimack County, which the U.S. EPA maps as Radon Zone 2 — moderate potential (predicted indoor average 2–4 pCi/L) — not the highest-risk Zone 1 (only Carroll County is Zone 1 in NH). That said, local Air Chek test data compiled at county-radon.info shows Merrimack County's average indoor reading is 5.2 pCi/L, above EPA's 4.0 pCi/L action level, so EPA still advises testing every home regardless of zone.
Why does Concord have radon at all?
The bedrock under the city is the USGS-named "Concord Granite," a Late Devonian two-mica granite whose type locality is the city of Concord itself — the same stone quarried on Rattlesnake Hill that built the NH State House. Uranium decay in this granite (documented in USGS Open-File Report 78-482) releases radon gas that seeps into basements and dissolves into groundwater, which is why testing matters here even in a moderate EPA zone.
Should I worry about radon in my Concord well water?
If you're on a private well, yes — it's a separate exposure path. The NH Radon Program (NH DHHS/NHDES) advises treating well water at or above 10,000 pCi/L always, and at 2,000–10,000 pCi/L when indoor air also tests over 4 pCi/L. Granite-area NH wells have reported radon over 30,000 pCi/L. We can test the water and install GAC or aeration treatment alongside air mitigation; for crawl spaces and fieldstone foundations we install sub-membrane depressurization systems.