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Rockingham County, New Hampshire

A shallow water table limits basements on 48% of Rockingham County's mapped land, a higher share than 64% of US counties and the 3rd highest of 10 New Hampshire counties. Shrink-swell clay limits houses without basements on under 1%.

13.5% of the county is in drought on the October 13, 2026 Drought Monitor map, down from 40.1% a week earlier. FEMA's flood data list 479 flood losses here since 2016, 19% of them in buildings with basements. 45% of homes were built before 1980, against 50% nationally; the median home dates from 1983.

Data as of October 13, 2026 · sources

<1%

expansive clay: shrink-swell limits slab homes

48%

high water table: limits basements

14%

in drought, October 13, 2026

45%

of homes built before 1980

Soil under Rockingham County

Expansive clay (limits slab homes)0.3%
High water table (limits basements)47.5%
Septic fields very limited89.7%
Clay swell (LEP, by area)0.9%
High-swell land (LEP 6%+)0.9%
Urban land, not rated1.3%
Mapped soil464,966 acres
Soil seriesShare hereSeries nationally: high water table
Canton17%n/a
Chatfield10%n/a
Hollis7%n/a
Freetown5%n/a
Montauk4%n/a
Scituate4%n/a
Strafford County: 39%Essex County: 45%Hillsborough County: 28%Merrimack County: 49%York County: 52%Middlesex County: 41%Belknap County: 42%Suffolk County: 11%Rockingham County StraffordEssexHillsboroughMerrimackYorkMiddlesexBelknapSuffolkRockingham
Rockingham County (heavy outline) and nearby counties, shaded by high water table share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas NH015 (2025-09-09)

What the numbers mean here

On 48% of Rockingham County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.

Rain over the 12 months to August 2026: 35.09 in, 11.74 in below the 1991-2020 average year of 46.83 in.

USDA rates 90% of the land very limited for septic absorption fields.

Drought

13.5% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 18 weeks, most recently on the August 4, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse100%
D1 moderate drought or worse13.5%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

479 flood losses since 2016, $14.5 million paid. The worst year was 2024, with 252. Foundations of the buildings, where recorded: 19% basements, 26% slabs, 33% crawl spaces, 22% elevated. Median water depth outside the building: 17 in.

YearFlood losses
20162
20176
201898
20196
20204
20210
202291
202320
2024252
20250
2026 to date0

Rain

Average year, 1991-202046.83 in
12 months to August 202635.09 in (-11.74)
202538.87 in (-7.96)
Wettest year since 18952006: 64.14 in
Driest year since 18951941: 29.15 in
Days with 1 inch or more, normal at EPPING (3 mi away)11.1

Homes

Housing units137,794
Median year built1983
Built before 198045%
Built 2000 or later23%
Owner-occupied78%
Median value, owner-occupied$497,500
Single-family detached65%

What repairs cost

Published ranges from cost guides, not quotes. More sources, and where they disagree.

WorkRangeSource
Basement waterproofing, US $3,000 to $10,000 Fixr, February 6, 2026
Sump pump installation, US $800 to $2,000 Fixr, January 31, 2025
Crawl space encapsulation, US $2,000 to $8,000 Fixr, August 29, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Strafford County, NH 21 mi 1% 39%
Essex County, MA 27 mi 0% 45%
Hillsborough County, NH 32 mi 3% 28%
Merrimack County, NH 36 mi 2% 49%
York County, ME 37 mi 3% 52%
Middlesex County, MA 38 mi 0% 41%
Belknap County, NH 40 mi 2% 42%
Suffolk County, MA 46 mi 0% 11%

Sources: USDA SSURGO (September 9, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status