Merrimack and Belknap Counties, New Hampshire
The most common soil here is Tunbridge, on about 7% of the land: a fine sandy loam, gritty and crumbly. Becket and Lyman come next.
About 61% of the land drains well, and 15% stays wet for long stretches; groundwater comes within two feet of the surface under 27% of it.
USDA rates 91% of the land very limited for a standard septic drain field, and 76% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 2% of the land floods occasionally or more, and bedrock lies within 40 inches under 37% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Merrimack and Belknap Counties, New Hampshire, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Merrimack and Belknap Counties, New Hampshire. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Water | 58K | Not rated | Not rated | ||
| Tunbridge-Lyman-Becket complex, 15 to 25 percent slopes, very stony | 57K | Well drained | C | Very limited | Very limited |
| Tunbridge-Lyman-Becket complex, 8 to 15 percent slopes, very stony | 56K | Well drained | C | Very limited | Very limited |
| Millsite-Woodstock-Henniker complex, 8 to 15 percent slopes, very stony | 45K | Well drained | C | Very limited | Very limited |
| Pillsbury fine sandy loam, 0 to 8 percent slopes, very stony | 29K | Poorly drained | D | Very limited | Very limited |
| Millsite-Woodstock-Henniker complex, 15 to 25 percent slopes, very stony | 25K | Well drained | B | Very limited | Very limited |
| Tunbridge-Lyman-Becket complex, 25 to 60 percent slopes, very stony | 23K | Well drained | C | Very limited | Very limited |
| Chatfield-Montauk-Hollis complex, 8 to 15 percent slopes, very rocky | 23K | Well drained | B | Very limited | Very limited |
| Millsite-Woodstock-Henniker complex, 3 to 8 percent slopes, very stony | 19K | Well drained | C | Very limited | Very limited |
| Metacomet fine sandy loam, 3 to 8 percent slopes, very stony | 18K | Moderately well drained | C | Very limited | Very limited |
| Moosilauke fine sandy loam, 3 to 8 percent slopes, very stony | 17K | Poorly drained | A/D | Very limited | Very limited |
| Chocorua mucky peat, 0 to 1 percent slopes | 16K | Very poorly drained | A/D | Very limited | Very limited |
| Croghan loamy fine sand, 0 to 8 percent slopes, wooded | 16K | Moderately well drained | A | Very limited | Very limited |
| Skerry fine sandy loam, 8 to 15 percent slopes, very stony | 14K | Moderately well drained | C/D | Very limited | Very limited |
| Skerry fine sandy loam, 0 to 8 percent slopes, very stony | 14K | Moderately well drained | C/D | Very limited | Very limited |
| Chatfield-Montauk-Hollis complex, 15 to 35 percent slopes, very rocky | 14K | Well drained | B | Very limited | Very limited |
| Lyman-Tunbridge-Rock outcrop complex, 35 to 60 percent slopes | 13K | Somewhat excessively drained | D | Very limited | Very limited |
| Metacomet fine sandy loam, 8 to 15 percent slopes, very stony | 12K | Moderately well drained | C | Very limited | Very limited |
| Tunbridge-Lyman-Becket complex, 0 to 8 percent slopes, very stony | 12K | Well drained | C | Very limited | Very limited |
| Champlain loamy fine sand, 3 to 8 percent slopes | 11K | Somewhat excessively drained | A | Not limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 76% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas. A geotechnical assessment is recommended before building.
Septic Systems
About 91% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.