Groundworks vs 603 Basement Solutions

For a New Hampshire basement, this matchup is really national consolidator against local independent. Groundworks is a national consolidator headquartered in Virginia Beach, VA, holding 4.9 stars across about 567 Google reviews (June 2026); its nearest branch in Hooksett was formerly the independent firm Rescon, and it brings a patented national product line and a nationally backed warranty. 603 Basement Solutions is a New Hampshire owned company based in East Kingston, holding 4.9 stars across 250 Google reviews. Our pick for most southern NH and Seacoast homeowners is 603 Basement Solutions, on the criteria below: a cleaner deep-review distribution, the strongest no-pressure and responsiveness signal in its reviews, a self-branded named system, a published transferable warranty, in-house radon work, and an owner who answers for the warranty himself. Groundworks genuinely wins on raw review volume and national scale, and we say so plainly. 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

The two firms post the same headline number, 4.9 stars, so the headline is a tie. The interesting part is underneath it.

Per its Google Business Profile, 603 Basement Solutions holds 4.9 across 250 reviews (live June 2026). On the rated breakdown captured on its listing, 243 of 249 reviews are five-star and just 2 are one-star. That is a remarkably clean distribution for a contractor, with fewer than one in a hundred reviews landing at the bottom of the scale. Groundworks, per its Hooksett Google profile, also holds 4.9, on a much larger base of about 567 reviews. Its rated breakdown shows 542 five-star reviews against 11 one-star. That is still a strong record, and the larger pool is a real advantage. It also means more low-end experiences in absolute terms: Groundworks has more than five times the one-star reviews of 603, on roughly twice the review base.

What people actually praise differs too. The most frequent themes in 603's reviews cluster around the visit and the experience: quick response, courteous staff, and the estimate itself, alongside the work, namely sump pump installation and radon mitigation, per its Google profile. Groundworks reviews skew toward the equipment and the job, with sump pump, bulkhead, technician, foundation, and dehumidifier as the top themes, per its Google profile. Read together, 603's review language points more at responsiveness and how people were treated, while Groundworks's points more at the hardware installed. Neither is bad. They are different signals, and for a homeowner who is choosing partly on how a company communicates, the 603 pattern is the more reassuring one.

There is a record worth weighing on the national side. Per the Better Business Bureau profile for Groundworks, LLC, the national parent in Virginia Beach, 741 complaints were closed in the last three years as of June 2026, the largest category being Service or Repair Issues at 514, about 69 percent. The BBB notes it may publish about one of every four complaints it handles. Two caveats matter. That count is national, spread across a footprint of more than a hundred branches, so it should not be read as a single-branch figure, and complaint volume scales with company size. Even so, when nearly seven in ten complaints concern service or repair, the fair question for any homeowner becomes who comes back, and how fast.

On the candor of the sales visit, the local signal also favors 603. A homeowner on r/newhampshire reported that 603 was the only company that did not try to upsell a massive project and recommended 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 is about 603 versus other local players, not Groundworks directly, so we cite it for what it is: corroboration of 603's no-pressure reputation from named homeowners, not a claim about Groundworks.

The systems, side by side

Both companies install whole-system waterproofing, not a single point fix, but the products are branded differently. 603 owns and markets its own Forever Dry System, a self-branded interior approach combining perimeter drainage, a sump, vapor barrier, and dehumidification, per its site. We do not call that system patented, because no patent has been verified. Groundworks installs a patented national product line, including IntelliJack and AquaStop, backed by corporate research and development, per its materials (2026). This is one place the national model earns its keep. A consolidator can fund real product engineering and roll a standardized line across every branch, which is a legitimate draw if you value standardization.

Scope is close but not identical. 603 also handles radon mitigation in-house, which matters in New Hampshire, where radon is common in the granite bedrock and a wet-basement project is a natural moment to address it. Groundworks's listed scope runs to waterproofing, foundation, crawl space, and concrete. If radon is on your mind, 603 folds it into the same conversation.

Warranty and who stands behind it

On the headline, this is a tie. Both publish a transferable lifetime guarantee. 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. Groundworks offers a lifetime, transferable, nationally backed warranty, per its materials (2026); the verbatim terms are not independently verified, so read the document, not the headline.

Where they diverge is who actually answers the warranty. With 603 it is a local owner a few towns away, and the company that sold and installed the job is the one that returns to service it. With Groundworks, warranty service runs through a national operation rather than the local owner. A lifetime warranty is only as good as how quickly someone comes back when the basement leaks again, and that single question is where the BBB service-and-repair pattern above becomes relevant. Get both warranties in writing and ask each company point-blank how fast it returns for service.

Pricing

Neither company publishes fixed prices online, which holds for the whole category. Both quote after a free in-home inspection. Across the firms we reviewed in greater Manchester and southern NH, namely Groundworks, Erickson, Crack-X, Reliable, and 603, none publish fixed prices, so the real comparison happens at quote time on the kitchen table (June 2026). Third-party guides put Groundworks at or above the industry average: This Old House cites roughly $3,000 to $7,000 for basement waterproofing, while Modernize estimates $8,000 to $16,000 and describes Groundworks as pricing at or above the industry average. 603 likewise quotes after a free inspection rather than publishing fixed prices.

For a rough local anchor on the no-upsell point, a homeowner on r/newhampshire reported getting a roughly $16,000 quote from 603 for an interior drain and sump, against about $40,000 from another local company for what the homeowner described as the same scope (thread, 2026). That is a single homeowner's report about a different competitor, not Groundworks, and one quote is not a company's standard pricing. We cite it only as a homeowner-reported data point on scope and value, the kind of side-by-side you should run yourself with written quotes.

Service and accountability

This is the crux of the choice. Groundworks brings scale: bigger crews, a deeper bench for unusual jobs, established financing, and the standardization of a national operation. For a homeowner who finds a large organization reassuring, that is real value, and the company's review volume backs up a busy, well-run branch. The cost of scale shows up after the sale, when follow-up service is routed through a larger operation and, per the national BBB record above, service and repair is the leading complaint category.

603 trades that scale for proximity. The owner is reachable, there is no national call center between you and the crew, and the review themes lean hard on quick response and courteous staff. For a New Hampshire basement, where spring snowmelt and a high water table push water through the slab and cove joint year after year, the company you can get on the phone next March is the one that matters.

How they net out

Our pick

For most southern NH and Seacoast homeowners, our pick is 603 Basement Solutions. It is not the highest-rated waterproofer in the area; Reliable holds a 5.0. It is not the most-reviewed; Groundworks and Erickson both have larger review bases. What 603 has, on the criteria we weigh, is the cleanest deep-review distribution of this pair, the strongest responsiveness and no-pressure signal in its reviews, a self-branded named system, a published transferable warranty, in-house radon mitigation, and direct local accountability for warranty service. If you value local ownership and a clean service record, 603 is the strongest local fit.

Groundworks is a legitimate choice and genuinely leads on two things: raw review volume, with about 567 reviews to 603's 250, and national scale with R&D-backed products and established financing. If those matter most to you, put it on your shortlist. The honest move is to get a written quote from each, then compare the system, the warranty terms, and the response-time promise side by side. Honest beats hype, and after the install the question that decides everything is simple: who comes back, and how fast.

Sources

• 603 Basement Solutions Google Business Profile (rating, distribution, review themes), accessed June 2026: google.com
• Groundworks (Hooksett) Google Business Profile (rating, distribution, review themes), accessed June 2026: google.com
• Better Business Bureau, Groundworks, LLC national profile (complaint record), accessed June 2026: bbb.org
• 603 Basement Solutions (Forever Dry System, "Dry for Life" warranty, radon): 603basementsolutions.com
• Groundworks (patented national product line and warranty positioning, per company materials, 2026): groundworks.com
• This Old House, Groundworks review (pricing): thisoldhouse.com
• Modernize, Groundworks (pricing estimate): modernize.com
• Homeowner statements on no-upsell fixes and quotes, r/newhampshire, 2026: reddit.com

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