Radon Systems LLC

Radon Systems LLC — also known on the ground as RadonGuys — is the radon mitigation company South Shore Redditors and hundreds of Google reviewers point to for a specific reason: the before-and-after numbers. Reviewers report radon levels dropping from double digits to a fraction of a picocurie after installation, and the company backs its work with a guarantee under 2.0 pCi/L. Based in Sutton, it designs and installs mitigation systems for radon in air and in well water, sells test kits, and installs sump pumps across Massachusetts. The numbers reviewers cite are specific and repeated: one home went from 10.1 to 0.4 pCi/L, another from 4.5 to 0.7, a third described levels that had been at 21 pCi/L dropping sharply after the install. Several reviews single out the technician by name — John, who owns the company and often runs jobs himself, gets credit for fast, courteous installs and for talking homeowners through where to route the pipe; Derek and Josh get similar praise for clean, efficient work. One 2026 review describes a genuinely difficult job — an 1890 house with several basement sections at different floor levels and foundation types — that the crew worked through successfully. Another homeowner in a condo complex needed a lengthy contractor-approval process before the board would sign off, and the paperwork was handled quickly enough to get it through. Reddit posts from 2024 and 2025 describe similarly quick, competent work, including one re-tooling of a dead existing system for $650. In March 2025, the national firm Protect Environmental announced it had acquired Radon Systems LLC; reviews through this past summer still describe working directly with the same named technicians, so the day-to-day experience doesn't appear to have changed. One clear exception stands out: an April 2026 review said the company quoted more than double the going rate to replace an expansion tank on an existing system, separate from the installation work everyone else describes. It's worth getting a second quote on any add-on repair work, even with an excellent track record on the mitigation installs themselves. The company's own history is also told two different ways on its site — one page traces it to Chapin Environmental, founded in Rhode Island in 1989 and renamed RadonGuys after a 1992 move to Massachusetts, while another says it's been installing radon systems since 1985 — worth knowing simply because the company has operated under more than one name. For radon testing or mitigation anywhere in Massachusetts, Radon Systems LLC has an unusually well-documented record of actually solving the problem, with real before-and-after numbers behind it. Get a second opinion on any repair or add-on pricing, and don't be thrown off if you see the company referred to as RadonGuys or the Radon Company — it's the same outfit.