Appendix B - Key to HIS Soil Types

Source: Current official PDF (Appendix B, pages 219-224 of the March 11, 2026 ordinance PDF).

Source: Society of Soil Scientists off Northern New England, High Intensity Soils Maps for New Hampshire - Standards and Origins, January, 1987, p. 8, p. 9.

This key is used in determining soil types that are utilized in high intensity soil surveys for administration of lot size by soil type and wetlands regulations. The soil types are defined as soils having the same soil characteristics of drainage class, parent material, restrictive features, and slope; and are designated by a five-part symbol, the parts being A, B, C, D, E.

Symbol A - Drainage Class.

CodeDescription
1excessively drained
2well drained
3moderately well drained
4somewhat poorly drained
5poorly drained
6very poorly drained
7not determinable (to be used only with Symbol B-6)

Symbol B - Parent Material.

CodeDescription
1Glaciofluvial Deposits (outwash/terraces)
2Glacial Till Material Marine or Glaciolacustrine Deposits
3Very fine sand and silt deposits
4Loamy/sandy over silt/clay deposits
5Silt and clay deposits
6Excavated, regraded or filled
7Alluvial Deposits
8Organic Materials - Fresh Water
9Organic Materials - Tidal Water

Symbol C - Restrictive Feature.

CodeDescription
1None.
2bouldery, with more than 15% of the surface covered with boulders (larger than 12 inches in diameter).
3mineral restrictive layer(s) are present in the soil profile less than 40 inches below the soil surface - such as hard pan, platy structure, clayey texture. For examples of soil characteristics that qualify for restrictive layer, see Soil Manual for Site Evaluations in New Hampshire, page 2-22, figure 2-8.
4bedrock present in the soil profile 0 to 40 inches below the soil surface (bedrock is either a lithic or paralithic contact - see Soil Taxonomy p. 48-49).
5subject to flooding.
6does not meet fill standards (see addendum - Standards For Fill Material) (only to be used with Symbol B-6).
XAreas where depth to bedrock is so variable that a single soil type cannot be applied will be mapped as a complex of soil types and will have a Symbol C of X.

Symbol D - Slope Class.

CodeDescription
B0 TO 8%
C8 TO 15%
D15 TO 25%
E25% +

Symbol E - High Intensity Soil Map Identifier.

The H is placed at the end of the soil type to identify the area mapped as meeting the standards for high intensity soil maps. If, as a preliminary planning tool, a soil map is made that does not meet the standards, but the soil scientist still prefers to use the connotative legend to identify the soils, a P (signifying a preliminary map) will be sued in place of the H, i.e. 111CP. Maps made with soil types ending with P do not meet the standards for high intensity soil maps and are not intended to be used for wetland Ordinance, lot size by soil type regulations, etc.

Some Examples.

  • 1. An excessively drained sand and gravel soil with on restrictive features on a 9% slope would be identified as: 111CH
  • 2. A moderately well drained glacial till soil with a hard pan, on a 4% slope would be identified as: 323BH
  • 3. A somewhat poorly drained clayey soil with firm consistence and high clay content in the substratum, on a 1% slope would be identified as: 453BH
  • 4. A very poorly drained organic soil located on the tidal marsh would be identified as: 691BH
  • 5. An area of well drained glacial till where bedrock is present, and the shallow soils are so intermixed with deep soils that they cannot be separated, on a 16% slope, would be identified as: 22XDH

Soil Type / Lot Size.

Soil TypeLot SizeSoil TypeLot SizeSoil TypeLot Size
111BH40000212BH7500023XCH100000
111CH45000212CH8000023XDH140000
111DH60000212DH9500023XEHNA
111EHNA212EHNA241BH50000
112BH75000213BH50000241CH75000
112CH80000213CH75000214DH100000
112DH95000213DH3100000241EHNA
112EHNA213EHNA243BH50000
114*HNA214*HNA243CG75000
11XBH8000021XBH80000243DH100000
111XCH10000021XCH100000243EHNA
11XDH14000021XDH140000244*HNA
11XEHNA21XEHNA24XBH90000
121BH40000221BH4000024XCH130000
121CH45000221CH4500024XDH180000
121DH60000221DH6000024XEHNA
121EHNA221EHNA251BH90000
122BH75000222BH75000251CH135000
122CH80000222CH80000251DH160000
122DH95000222DH95000251EHNA
122EHNA222EHNA253BH90000
124*HNA223BH50000253CH135000
12XBH80000223CH75000253DH160000
12XCH100000223DH100000253EHNA
12XDH140000223EHNA254*HNA
12XEHNA224*HNA25XBH130000
161BH5000022XBH8000025XCH190000
161CH5500022XCH10000025XDH240000
161DH7000022XDH14000025XEHNA
161EHNA22XEHNA261BH50000
164*HNA231BH40000261CH55000
166*HNA231CH45000261DH70000
16XBH90000231DH60000261EHNA
16XCH110000231EHNA263BH60000
16XDH150000233BH50000263CH85000
16XEHNA233CH75000263DH110000
211BH40000233DH100000263EHNA
211CH45000233EHNA264*HNA
211DH60000234*HNA266*HNA
211EHNA23XBH8000026XBH90000
26XCH11000033XBH115000412BH145000
26XDH15000033XCH155000412CH190000
26XEHNA33XDH205000413BH90000
275*HNA33XEHNA413CH135000
311BH60000341BH75000414*HNA
311CH90000341CH10000041XBH150000
311DH120000341DH12500041XCH180000
311EHNA341EHNA421BH75000
312BH95000343BH75000421CH115000
312CH125000343CH100000422BH130000
312DH155000343DH125000422CH165000
312EHNA343EHNA423BH90000
313BH60000344*HNA423CH135000
313CH9000034XBH115000424*HNA
313DH12000034XCH15500042XBH150000
313EHNA34XDH20500042XCH180000
314*HNA34XEHNA431BH115000
31XBH100000351BH90000431CH150000
31XCH120000351CH135000433BH115000
31XDH160000351DH160000433CH150000
31XEHNA351EHNA434*HNA
321BH50000353BH9000043XBH175000
321CH75000353CH13500043XCH235000
321DH100000353DH160000441BH115000
321EHNA353EHNA441CH150000
322BH85000354*HNA433BH115000
322CH10000035XBH130000443CH150000
322DH13500035XCH190000444*HNA
322EHNA35XDH24000022XBH175000
323BH6000035XEHNA44XCH235000
323CH90000361BH70000451BH135000
323DH120000361CH100000451CH205000
323EHNA361DH130000453BH135000
324*HNA361EHNA453CH205000
32XBH100000363BH70000454*HNA
32XCH120000363CH10000045XBH195000
32XDH160000363DH13000045XCH285000
32XEHNA363EHNA461BH105000
331BH75000364*HNA461CH150000
331CH100000366*HNA463BH105000
331DH12500036XBH110000463CH150000
331EHNA36XCH130000464*HNA
333BH7500036XDH170000466*HNA
333CH10000036XEHNA46XBH165000
333DH125000375*HNA46XCH195000
333EHNA411BH90000
334*HNA411CH135000

Limiting Characteristics.

The soil types listed below have one or more limiting characteristics that make the soil type "NA" or require on-site investigation, no matter what other characteristics of the soil may be present.

Soil TypeMinimum Lot Size
5***HNA, poorly drained soil
6***HNA, very poorly drained soil
*75*HNA, floodplain soil
*66*HNA, fill does not meet the Standards for Fill Material (see Key to Soil Types)
76**HOn-Site evaluation needed

The Soil Type symbols are explained in the Key to Soil Types.

"NA" means not allowed

"*" means any slope or any number

NOTE:

  • 1) The lot size requirements in the preceding table do not apply to lots having municipal sewerage.
  • 2) The lot size requirements in the preceding tables may be reduced by 1/3 for lots having municipal water and no municipal sewerage.

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