Soil series profile

Power soil series

Power is a well drained soil with a silt loam surface, mapped on 215,961 acres in 15 counties across 2 states. Hydrologic group C.

#1645 by mapped area fine-silty Xerollic Haplargids (Aridisols)

Drainage class: Well drained
Hydrologic group: C
Typical topsoil pH: 7.2
Mapped area: 216k

Typical Power 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 Power horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–14 in (A)	Silt loam	7.2	20%	11%	1.5%
14–28 in (Bt)	Silty clay loam	7.5	30%	7%	0.75%
28–72 in (Bk)	Silt loam	8.4	18%	31%	0.25%

Representative values from the most extensive Power map unit (Power-McCain complex, 1 to 6 percent slopes, survey area ID704). 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 Power soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Power soils is neutral: pH 7.2 (most land between 7.0 and 7.2), the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Power acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (98% of mapped Power acres).

100% of mapped Power acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 99% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.

For a septic system

For conventional septic absorption fields, NRCS rates 64% of the acres in mapped Power soils very limited, 36% 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 Power soil is found

Mapped acres

Power is mapped in Idaho and Oregon.

Counties with the most mapped Power soil
County	Acres	Share of county land
Jerome County, ID	47,164	14.3%
Canyon County, ID	36,207	11.3%
Ada County, ID	31,391	5.5%
Minidoka County, ID	22,726	5.2%
Lincoln County, ID	19,725	3.0%
Gooding County, ID	15,550	3.9%
Elmore County, ID	11,469	0.9%
Payette County, ID	10,767	4.8%
Gem County, ID	9,125	3.2%
Blaine County, ID	4,142	0.4%
Owyhee County, ID	2,624	0.1%
Malheur County, OR	2,312	0.0%
Washington County, ID	2,295	0.3%
Twin Falls County, ID	416	0.0%
Adams County, ID	46	0.0%

Septic absorption fields

NRCS rating, share of Power acres

Not limited 0%

Somewhat limited 36%

Very limited 64%

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

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Septic tank absorption field rating across mapped Power acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	35.8%
Very limited	64.2%

Drainage, water table and flooding

Share of Power 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 1–5% (median 3%).
Topsoil organic matter: Median 1.5%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 100%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

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

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Drainage class across mapped Power acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	100.0%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 1%

C: slow infiltration 99%

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%

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

Show as a table

Hydrologic soil group across mapped Power acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	1.1%
C: slow infiltration	98.9%
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%

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 Power (component kind "Series") in SSURGO: 215,961 acres.
Method: Shares are by mapped acres of Power components. The profile comes from the single largest Power component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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