Soil series profile

Calvin soil series

Calvin is a well drained soil with a channery silt loam surface, mapped on 560,121 acres in 62 counties across 6 states. Hydrologic group B.

#469 by mapped area loamy-skeletal Typic Dystrudepts (Inceptisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 5.3
Mapped area: 560k

Typical Calvin profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Calvin horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–8 in (H1)	Channery silt loam	5.3	17%	30%	1.25%
8–27 in (H2)	Channery loam	5.3	23%	35%	0.75%
27–34 in (H3)	Extremely channery loam	5.3	23%	33%	0.25%
34–38 in (R)	Unweathered bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Calvin map unit (Calvin stony silt loam, high base substratum, 35 to 70 percent slopes, survey area WV603). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Calvin soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Calvin soils is strongly acidic: pH 5.3 (most land between 5.0 and 5.8). Most vegetables and lawn grasses do best around 6.0 to 7.0, so lime is often needed; blueberries, azaleas and rhododendrons like it as it is.

Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Calvin acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is channery silt loam (67% of mapped Calvin acres).

>99% of mapped Calvin acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.

For a septic system

For conventional septic absorption fields, NRCS rates >99% of the acres in mapped Calvin soils very limited, 0% somewhat limited and 0% not limited.

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Calvin soil is found

Mapped acres

Calvin is mapped in Pennsylvania, West Virginia, Maryland, Virginia, Tennessee and North Carolina. The 60 counties with the most Calvin acres:

Counties with the most mapped Calvin soil
County	Acres	Share of county land
Randolph County, WV	83,446	15.9%
Dauphin County, PA	42,301	13.3%
Bedford County, PA	41,852	6.6%
Garrett County, MD	39,304	8.7%
Perry County, PA	32,332	9.4%
Schuylkill County, PA	26,903	5.5%
Fulton County, PA	23,186	8.4%
Preston County, WV	20,961	6.2%
Pendleton County, WV	20,346	5.9%
Pocahontas County, WV	17,480	3.6%
Morgan County, WV	17,292	13.4%
Rockingham County, VA	17,232	3.8%
Tucker County, WV	16,950	7.4%
Huntingdon County, PA	15,504	2.8%
Johnson County, TN	14,769	7.7%
Hancock County, TN	10,170	7.1%
Carter County, TN	9,866	4.5%
Tazewell County, VA	9,672	3.3%
Northumberland County, PA	8,347	2.9%
Berkeley County, WV	6,599	3.8%
Washington County, MD	6,567	2.3%
Allegany County, MD	5,161	1.9%
Centre County, PA	5,058	0.7%
Scott County, VA	4,586	1.6%
Berks County, PA	4,286	0.8%
Hawkins County, TN	3,911	1.3%
Hardy County, WV	3,897	1.3%
Washington County, VA	3,562	1.3%
Union County, PA	3,460	1.7%
Greenbrier County, WV	3,162	0.6%
Snyder County, PA	2,776	1.3%
Mineral County, WV	2,750	1.5%
Lycoming County, PA	2,352	0.3%
Russell County, VA	2,347	0.9%
Monroe County, TN	2,250	0.6%
Greene County, TN	2,212	0.6%
Bland County, VA	2,140	1.5%
Unicoi County, TN	1,832	1.5%
McKean County, PA	1,629	0.3%
Grant County, WV	1,616	0.7%
Lebanon County, PA	1,600	0.7%
Columbia County, PA	1,370	0.4%
Smyth County, VA	1,230	0.7%
Clinton County, PA	1,100	0.2%
Craig County, VA	1,076	1.3%
Somerset County, PA	971	0.1%
Franklin County, PA	741	0.2%
Montour County, PA	622	0.7%
Blair County, PA	448	0.1%
Blount County, TN	439	0.1%
Wise County, VA	365	0.2%
Madison County, NC	307	0.1%
Lehigh County, PA	225	0.1%
Cameron County, PA	214	0.1%
Hampshire County, WV	201	0.1%
Fayette County, PA	187	0.0%
Northampton County, PA	116	0.0%
Luzerne County, PA	116	0.0%
Buchanan County, VA	76	0.0%
Monroe County, PA	74	0.0%

Septic absorption fields

NRCS rating, share of Calvin acres

Not limited 0%

Somewhat limited 0%

Very limited >99%

Not rated <1%

Septic tank absorption field rating across mapped Calvin acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Calvin acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	99.7%
Not rated	0.3%

Drainage, water table and flooding

Share of Calvin acres

Depth to seasonal high water table: None reported within about 6.5 feet (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 6–53% (median 20%).
Topsoil organic matter: Median 1.2%.

Drainage class

Excessively drained 0%

Somewhat excessively drained <1%

Well drained >99%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated <1%

Drainage class across mapped Calvin acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Calvin acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.3%
Well drained	99.4%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	0.3%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 9%

B: moderate infiltration 82%

C: slow infiltration 9%

D: very slow infiltration (clayey, shallow or wet) 0%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Not rated <1%

Hydrologic soil group across mapped Calvin acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Calvin acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	8.7%
B: moderate infiltration	81.7%
C: slow infiltration	9.3%
D: very slow infiltration (clayey, shallow or wet)	0.0%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%
Not rated	0.3%

Sources & data dates

Source: USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date: SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope: All map unit components named Calvin (component kind "Series") in SSURGO: 560,121 acres.
Method: Shares are by mapped acres of Calvin components. The profile comes from the single largest Calvin component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Calvin.