603 Basement Solutions vs NH Dry Basement

This is a matchup of two locally owned New Hampshire waterproofers that mostly cover different ends of the Seacoast. 603 Basement Solutions works out of East Kingston in southern NH and the southern Seacoast, holding 4.9 stars across 250 Google reviews (June 2026). NH Dry Basement, short for NH Dry Basement, works out of Barrington in Strafford County and covers roughly a one-hour radius of the Dover and Barrington area, the north Seacoast; it holds 4.9 stars across 76 Google reviews (June 2026). Read on the headline five-star share, NH Dry actually edges ahead, 98.7 percent against 603's 97.6 percent, and we show that plainly below. Even so, our pick for most homeowners weighing the two is 603 Basement Solutions, on depth and breadth: that 97.6 percent sits on 250 rated reviews, a far larger sample than NH Dry's 75, and 603 adds a self-branded named system, a published transferable warranty, in-house radon work, and BBB accreditation since 2022. NH Dry is a genuinely strong smaller local, and if you live up near Dover or Barrington it may simply be the more convenient call. Here is the full comparison, with sources.

Our findings follow our published methodology. Every figure below is dated and sourced.

At a glance

What homeowners report

Both companies post the same headline star average, 4.9, so the headline is a tie. The five-star share underneath it is where they separate, and it separates in NH Dry's favor before you weigh sample size.

Per its Google Business Profile, NH Dry Basement holds 4.9 across 76 reviews (June 2026). On the rated breakdown captured on its listing as of June 1, 2026, 74 of 75 reviews are five-star and just 1 is one-star, which works out to 98.7 percent five-star. That is a near-perfect record, and we are not going to dress it down. Per its Google Business Profile, 603 Basement Solutions holds 4.9 across 250 reviews (live June 2026); on the rated breakdown captured May 19, 2026, 243 of 249 reviews are five-star, with 3 four-star, 1 two-star, and 2 one-star, which works out to 97.6 percent five-star. So on the single number the gauge below shows, NH Dry leads.

Now the reading note that our methodology calls for, because a percentage is only as trustworthy as the count behind it. NH Dry's 98.7 percent rests on 75 rated reviews. 603's 97.6 percent rests on 249. A near-perfect share on a smaller base is more fragile than a slightly lower share on a larger one: with NH Dry's 75 reviews, one more bad experience moves the number by more than a point, while at 603's scale a single review barely registers. Put another way, 603 has earned more than three times the rated reviews and still keeps its one-star rate to a hair under one percent. Both records are excellent. The difference is that 603's has been tested against many more jobs, and that durability is what we weight when the headline numbers are this close.

The review themes point in a similar, reassuring direction for both. NH Dry's most-mentioned topics are sump pump installation (13), basement waterproofing (11), estimate (7), dry basement (6), respectful crew (4), competitive quote (4), and honest feedback (3), per its Google profile. The "respectful crew," "competitive quote," and "honest feedback" cluster is exactly the language a homeowner wants to see, and it shows up unprompted in the reviews rather than in marketing copy. 603's top themes are sump pump installation (30), radon mitigation (29), basement waterproofing (21), quick response (20), courteous staff (18), and estimate (18), per its Google profile. The shapes rhyme: both lean toward sump and waterproofing work, courteous treatment, and the estimate experience. 603's set is simply larger and includes a strong radon signal that NH Dry's does not.

On the candor of the sales visit, 603 also carries a documented outside reputation. A homeowner on r/newhampshire reported that 603 was the only company that did not try to upsell a massive project, recommending the least-invasive correct fix, an interior French drain tied to a sump rather than a slab replacement, with an architect and a former industry insider in the same thread endorsing that approach (thread, 2026). That thread does not mention NH Dry at all, so we cite it only for what it is: corroboration of 603's no-pressure reputation, not any comparison against NH Dry, whose own "honest feedback" and "competitive quote" themes stand on their own Google record.

The biggest difference: depth and scope

The clearest factual gap here is not quality, since both rate near the top. It is depth of offering and the size of the record behind each company.

603 owns and installs a self-branded named system, the Forever Dry System, a full interior approach combining perimeter drainage, a sump, a wall vapor barrier, and dehumidification, per its site. We do not call that system patented, because no patent has been verified. NH Dry does not market a self-branded named system; its listed work is waterproofing and ventilation, per its Google profile and website. A named system is not a guarantee of better work, but it does mean the company that designed the approach is the one that answers for it later.

Scope is the other split. 603's listed scope runs to waterproofing, foundation, crawl space, and radon mitigation, and it does the radon work in-house. That matters in New Hampshire, where radon is common in the granite bedrock and a wet-basement project is a natural moment to address it; 603's reviews mention radon mitigation 29 times, per its Google profile. NH Dry's listed scope is waterproofing and ventilation, with no radon offering noted. If radon is on your mind, 603 folds it into the same conversation; with NH Dry you would be lining up a separate radon contractor.

Both are locally owned independents, which is the shared strength of this matchup. Neither routes you through a national call center, and with either one the owner is reachable. The practical difference is geography: 603 is the natural fit for East Kingston, Exeter, and the southern Seacoast, while NH Dry is the natural fit up around Dover, Barrington, and the rest of Strafford County, which is its home turf.

Warranty and BBB record

On warranty, the two diverge in what each one publishes. 603 publishes a "Dry for Life" transferable guarantee, per its site; treat the exact written terms as marketing wording until you have the contract in hand. NH Dry does not state a warranty on its website, so if you go that route, ask for the terms in writing at the quote and confirm whether coverage transfers to a future owner. A published, transferable guarantee is a real point in 603's column, but the document is what counts, so read it either way.

The BBB record splits the same direction. 603 holds an A+ rating and has been BBB accredited since 2022, per its BBB profile, accessed June 2026. NH Dry is not assessed on the BBB in our records, which is not a mark against it; plenty of good small contractors never pursue accreditation. It simply means there is one fewer independent record to lean on, and 603 has that record.

Pricing

Neither company publishes fixed prices online, which holds across the whole category. Both quote after a free in-home inspection, because the number depends on the basement's perimeter, where the water comes from, and the fix. The honest comparison happens at quote time, on the same scope, in writing.

For a local anchor on the no-upsell point, a homeowner on r/newhampshire reported a roughly $16,000 quote from 603 for an interior drain and sump, and described 603 as the company that proposed the least-invasive correct fix rather than the biggest job (thread, 2026). That is one homeowner's report about one project, not a price list, and the thread does not mention NH Dry at all, so it is not a point against NH Dry. NH Dry's own "competitive quote" review theme suggests its pricing reads as fair to its customers, but that is a review signal, not a published figure. Get a written quote from each on identical scope and compare those, not the reputations.

How they net out

Our pick

For most homeowners weighing these two, our pick is 603 Basement Solutions, on depth and breadth. To be clear about what that is not: it is not the higher-rated company on five-star share, since NH Dry leads there at 98.7 percent to 603's 97.6 percent, and the gauge above shows it. Our call rests on the rest of the record. 603's 97.6 percent sits on 249 rated reviews to NH Dry's 75, which is a far more tested sample; 603 owns a self-branded named system where NH Dry markets none; 603 publishes a transferable "Dry for Life" guarantee where NH Dry states no warranty on its site; 603's scope includes in-house radon where NH Dry's does not; and 603 carries A+ BBB accreditation since 2022, where NH Dry is not assessed here. Taken together, that is the broader, deeper, more documented offering.

And NH Dry Basement earns its due. It posts the highest five-star share of this pair, its review themes run on honest feedback, respectful crews, and competitive quotes, and it is locally owned. For a homeowner up in Dover, Barrington, or the rest of Strafford County, NH Dry is the closer company and a strong one, and convenience plus a near-perfect local record is a legitimate reason to choose it. The honest move is the same either way: get a free inspection and a written quote from each, then compare scope, warranty terms in writing, and how fast each promises to return for service. Honest beats hype, and it is usually the comparison that holds up after the crew leaves.

Sources

• 603 Basement Solutions Google Business Profile (rating, distribution, review themes), accessed June 2026: google.com
• NH Dry Basement Google Business Profile (rating, distribution, review themes), accessed June 2026: google.com
• 603 Basement Solutions website (Forever Dry System, "Dry for Life" warranty, radon), accessed June 2026: 603basementsolutions.com
• NH Dry Basement website (scope: waterproofing and ventilation), accessed June 2026: nhdrybasement.com
• BBB accreditation status for 603 (A+, accredited 2022) and NH Dry (not assessed here), per BBB profiles, accessed June 2026
• Homeowner statements on 603's no-upsell fix and quote, r/newhampshire, 2026: reddit.com

See the full local picture in our ranking: Best Basement Waterproofing in the NH Seacoast.