Dover, New Hampshire: what the ground under the city is like
Dover sits in Strafford County, on glaciated new england upland. The soil mapped here is predominantly classified well drained — and that classification, not the rainfall total, is what decides how a basement behaves.
29% of the mapped soil area around Dover is wet enough that the USDA describes it as needing artificial drainage.
Linear extensibility 2.9% — low.
Shallowest annual water table around 85 cm (2.8 ft).
Values are for Strafford County, which is what the soil survey resolves to. Full county report · soil map for a specific address.
The ground under Dover
Glaciated New England upland. Stony basal till over crystalline bedrock, often with a hardpan
A hardpan under thin till creates a perched water table — water stands above an impermeable layer even though the regional water table is deep. It is the commonest cause of a wet basement in New England. Expansive clay is largely absent.
When it shows up here
| Water | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ground movement | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
Water peaks with the March–April thaw, when frozen ground stops absorbing and meltwater plus spring rain arrive together. If a basement here leaks once a year, that is when.
Climate pattern for this physiographic region, not a forecast for your house and not from the soil survey. It answers a question homeowners actually ask: when does this show up.
What repairs cost in New Hampshire
| Reference job | Modelled range |
|---|---|
| Interior drain along two walls + sump pump | $5,450–$11,700 |
| Exterior excavation of one 40 ft wall | $4,100–$11,650 |
| Underpinning on 10 piers | $16,200–$34,550 |
Regional factor for NH: ×1.08. Full cost breakdown for New Hampshire · run your own dimensions.
ZIP codes in Dover
03820, 03821, 03822
Soil does not stop at a city boundary, and neither does this data — every ZIP code above resolves to the same county soil survey. For the individual survey polygons around one address, use the soil map.
Other places in Strafford County
Questions about Dover
Is the soil the same everywhere in Dover?
No. These values describe Strafford County as a whole, which is the unit the soil survey publishes. Within a city, map units change over a few hundred metres — the soil map draws the actual polygons around a point and is the honest answer for one address.
Which contractor should I call in Dover?
We do not rank or recommend individual firms and we are not one. What this page is for is knowing which kind of work the ground here points to before anyone quotes you, and which claim to check. If you want quotes, the form below passes your request to the named networks.
Does this replace an inspection?
No. It tells you what the ground is; an inspection tells you what your building is doing on it. The useful order is: read this, print the brief for your county, then have someone look.
Get quotes in Dover
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