In March 2007 an engineering firm told Wolfeboro it had a “high degree of confidence” that a 35-acre parcel would take the town’s treated wastewater into the ground. The town bought it for a million dollars. Discharge started March 3, 2009. By April 17 groundwater was surfacing, by April 20 a slope had failed, and by June 8 there was a significant sinkhole along the northwest side. A federal jury later awarded the town $7,658,532. If Wolfeboro can be wrong about whether ground drains, so can you — which is why we dig a pit and watch it before designing anything.
That site was supposed to handle 600,000 gallons a day. It managed something closer to 340,000, and the lawsuit that followed turned on soil analysis and on slope stability and seepage issues that should have shown up in the site work. The town won on every claim in May 2014 and settled that September for $7.5 million. It’s an expensive, extremely local lesson in the thing we say on every job: how ground behaves under water is a question you answer by testing, not by looking at it.
The mapping backs it up. NRCS puts 3,499 acres of Wolfeboro in poorly drained hydric soils and another 1,131 acres in very poorly drained — roughly 4,600 acres that are wet by definition, not by bad luck. The aquifers under town are thin as aquifers go, most of them mapped at 2,000 square feet per day of transmissivity or less, and anything at or under 1,000 isn’t considered high-yield at all. Translation: there isn’t a lot of deep, thirsty gravel here. A dry well that works beautifully on an outwash lot in the next town over can surcharge and back up on a Wolfeboro hillside.
And the brooks move fast. The FEMA panels show Zone AE floodplain along Young’s Brook and Ryefield Brook, not just around the lakes, and Willey Brook, Mink Brook and the Smith River all once carried enough water to turn mill wheels. The Smith is the outlet from Lake Wentworth into Winnipesaukee, so a fair share of the east side of town drains through it. Water here has somewhere to go. The trouble starts when it decides your cellar is on the way.
If somebody promises you a dry well without digging a test pit first, get a second opinion. The town spent seven figures learning that ground which looks like it drains sometimes doesn’t, and a pit and a bucket of water costs an hour.
We start uphill, not at the wall. Most wet basements in this town are hillside basements taking groundwater moving sideways through till, and the fix is a curtain drain cut across the slope above the house — perforated pipe in stone, wrapped, set below the level of the problem, running to daylight. Daylight is the whole game. If there’s a place lower than the footing that we can legally discharge to, the drain works forever with no moving parts. If there isn’t, we’ll say so and talk about a sump, which is a pump, which is a thing that fails during the storm.
Dry wells and infiltration trenches only go in where a test pit has proven the ground takes water, and we dig that pit and watch it rather than assuming. On the flat wet ground — and there are thousands of acres of it here — infiltration is the wrong tool and a graded swale to a suitable outlet is the right one. Roof water gets taken away from the foundation by pipe, out past the backfill zone, because the backfill is looser than what it replaced and will happily funnel every downspout straight down your wall.
Inside 250 feet of Winnipesaukee, Lake Wentworth, Crescent Lake, Rust Pond or Mirror Lake, earth-moving falls under the state Shoreland rules and the erosion controls aren’t optional. Near a mapped wetland or a brook crossing, there’s a state wetlands permit involved and it takes the time it takes. We tell you that at the quote, not halfway through the dig, and we don’t start work that needs a permit we don’t have.
Curtain and French drains in Wolfeboro run $2,000–$8,000 depending on length, depth and how far it is to daylight; regrading, swales and repiping downspouts usually come in under that. Infiltration work gets quoted only after a test pit proves the ground will take it. Culverts and brook crossings are priced per site. Flat quote.
Sometimes it will. But a dry well only works if the soil under it actually accepts water at volume, and most of Wolfeboro is till and hydric ground rather than outwash gravel. NRCS maps roughly 4,600 acres of poorly or very poorly drained soil in town. We dig a pit, fill it, and time it before recommending one.
A curtain drain is cut across a slope above the house to intercept groundwater before it reaches the foundation. A French drain generally sits at the footing and handles what already got there. On a Wolfeboro hillside the curtain drain is usually the one that solves it, because the water is arriving sideways rather than rising from below.
Often, yes. Any earth-moving within 250 feet of a lake or pond falls under the state Shoreland Water Quality Protection Act, and work in or near a mapped wetland or a brook needs a state wetlands permit. Simple regrading well away from water usually doesn’t. We sort out which one you’re in before quoting.
Generally the landowner’s, on a private drive. Wolfeboro’s driveway permit puts the drainage structures needed to maintain roadside drainage on the owner, and a collapsed culvert backs water into the town ditch as well as your drive. Replacing one is a half-day job if the road doesn’t have to be cut. Ask before you dig near the travelled way.
Curtain drains need open ground, so realistically the season runs April into November, same as digging generally. Frost here is four feet and better. What we can do in winter is look at it while the water’s actually running, which is honestly the best time to diagnose a problem and the worst time to bury pipe.
Free site walks, test pits before quotes, flat pricing, and a crew that knows Lakes Region ground.
Tell us where the property is and what you’re trying to do. We’ll walk the site, talk it through, and give you a straight, flat quote.
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