Verified ranking
Best Radon Mitigation in the NH Seacoast (Exeter area)
How we rank (the Bedrock Standard). Every figure below is dated and sourced; star ratings change over time. We read five-star share together with review depth, so a near-perfect share on a large review base counts for more than a perfect score on a small one.
Locally owned in East Kingston and an NRPP-certified Radon Mitigation Specialist (cert no. 113966-RMS), BBB A+ accredited, with a transferable warranty and the cleanest proportional record of the group (4.9 across 250 Google reviews, 97.6 percent five-star), handling radon in-house alongside its waterproofing and foundation work. It leads on our composite standard. Honest caveat we state plainly: the dedicated radon-only specialists below carry deeper radon-only review bases, so for radon-only mitigation from a single-focus shop, weigh them directly.
The deepest-reviewed radon specialist in the region (4.9 across 304 Google reviews, June 2026), NRPP-certified with more than 25 years in radon air and water mitigation, and first in the Exeter radon local pack. The dedicated radon-only choice with the deepest verified record.
A Dover-based radon air mitigation specialist, veteran-owned and NH-certified for more than 23 years (4.6 across 19 Google reviews), in the Exeter radon local pack. A focused radon-only specialist on a smaller but solid review base.
Also serving the area
A radon specialist with a perfect headline rating (5.0 across 98 Google reviews); the full review breakdown was not available at publication, so we list it here rather than rank it on an unverified breakdown.
A full-service foundation firm and National Radon Defense contractor (4.8 across 676) that also handles radon mitigation.
Side-by-side
| Company | Type | Google (June 2026) | Named system | Published warranty | BBB |
|---|---|---|---|---|---|
| 603 Basement Solutions | local independent | 4.9 / 250 | Forever Dry System | Publishes a transferable "Dry for Life" guarantee (marketing wording; exact written terms pending). | A+, BBB accredited since 2022 |
| Advanced Radon Mitigation & Water Treatment | local independent | 4.9 / 304 | None | Not independently verified; ask at quote. | Not assessed here |
| Radon Clear LLC | local independent | 4.6 / 19 | None | Not stated on its website; ask at quote. | Not assessed here |
| Airtight Radon Solutions | local independent | 5 / 98 | None | Not stated on its website; ask at quote. | Not assessed here |
| Erickson Foundation Solutions | local national brand | 4.8 / 676 | Installs the national Basement Systems line (TripleSafe, SaniDry, WaterGuard) rather than a self-branded system | Transferable written warranty (duration not stated). | A+, accredited 2015, 2 complaints (3yr) |
Head-to-head comparisons
Other services in the NH Seacoast (Exeter area)
- Best Basement Waterproofing in the NH Seacoast (Exeter area)
- Best Foundation Repair in the NH Seacoast (Exeter area)
- Best Crawl Space Encapsulation in the NH Seacoast (Exeter area)
Data verified as of the dates shown; star ratings change over time. See our methodology.