Soil series profile

Penistaja soil series

Penistaja is a well drained soil with a fine sandy loam surface, mapped on 708,135 acres in 17 counties across 3 states. Hydrologic group B.

#331 by mapped area fine-loamy Ustic Haplargids (Aridisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 7.5
Mapped area: 708k

Typical Penistaja 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 Penistaja horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–2 in (H1)	Fine sandy loam	7.5	15%	69%	1.5%
2–18 in (H2)	Sandy clay loam	7.5	25%	57%	0.75%
18–58 in (H3)	Fine sandy loam	7.5	18%	66%	0.25%
58–84 in (H4)	Gravelly loamy sand	7.5	8%	84%	0.25%

Representative values from the most extensive Penistaja map unit (Penistaja-Begay complex, 1 to 8 percent slopes, survey area AZ714). 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 Penistaja soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Penistaja soils is slightly alkaline: pH 7.5 (most land between 7.2 and 7.5). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).

Loamy topsoil (loam, silt loam and similar) covers 91% of mapped Penistaja acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is fine sandy loam (64% of mapped Penistaja acres).

100% of mapped Penistaja 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 9% of the acres in mapped Penistaja soils very limited, 45% somewhat limited and 45% not limited (2% not rated, such as urban land, pits or water).

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 Penistaja soil is found

Mapped acres

Penistaja is mapped in New Mexico, Arizona and Utah.

Counties with the most mapped Penistaja soil
County	Acres	Share of county land
Cibola County, NM	139,497	5.5%
Torrance County, NM	98,347	4.6%
Sandoval County, NM	81,500	4.1%
Navajo County, AZ	74,015	1.3%
Lincoln County, NM	73,165	2.7%
Socorro County, NM	47,608	1.3%
Bernalillo County, NM	34,718	4.6%
San Juan County, NM	26,834	0.7%
Catron County, NM	20,578	0.9%
Rio Arriba County, NM	14,855	0.5%
Valencia County, NM	9,651	1.4%
McKinley County, NM	9,324	0.3%
Kane County, UT	6,116	0.2%
Mohave County, AZ	5,449	0.1%
Coconino County, AZ	4,048	0.0%
Apache County, AZ	2,836	0.0%
Los Alamos County, NM	549	2.1%

Septic absorption fields

NRCS rating, share of Penistaja acres

Not limited 45%

Somewhat limited 45%

Very limited 9%

Not rated 2%

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

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Septic tank absorption field rating across mapped Penistaja acres.
Category	Share of acres
Not limited	44.8%
Somewhat limited	44.7%
Very limited	8.8%
Not rated	1.6%

Drainage, water table and flooding

Share of Penistaja 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 3–6% (median 4%).
Topsoil organic matter: Median 1.4%.

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 Penistaja acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Penistaja 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 90%

C: slow infiltration 8%

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 2%

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

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Hydrologic soil group across mapped Penistaja acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	90.1%
C: slow infiltration	8.3%
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	1.6%

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 Penistaja (component kind "Series") in SSURGO: 708,135 acres.
Method: Shares are by mapped acres of Penistaja components. The profile comes from the single largest Penistaja component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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