Soil and perc tests in Parker County, Texas

USDA rates most of the soil in Parker County Very limited for septic absorption fields — 76.7% of the rated acres. Parker County calls this a site and soil evaluation. A sanitarian, an engineer, or a certified site evaluator must perform it. USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-12

Very limited

USDA rating, 76.7% of rated acres

checked 2026-09-12

Slow water movement

Most common limiting reason

checked 2026-09-12

Yes

Site evaluation required

checked 2026-09-23

What is a perc test and does Parker County require one?

Yes. Parker County calls this a site and soil evaluation. A sanitarian, an engineer, or a certified site evaluator must perform it.

The test tells the team what the lot can hold.

Parker County Permitting Department — Permitting Procedures for Your On-Site Sewage Facility · checked 2026-09-23

How USDA rates the ground in Parker County

Very limited across most of the county — 76.7% of the rated acres. A rating describes the ground, not a parcel. The county's site evaluation decides each lot.

Very limited — 373,098 acres — 76.7% of 486,416 rated acres.
Somewhat limited — 113,318 acres — 23.3% of 486,416 rated acres.
Not rated — 93,566 acres, excluded from the denominator — mostly urban land and water.

76.7% of 486,416 rated acres. 93,566 acres unrated. Survey area TX367 version 24, established 2025-09-05.

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-12

What limits absorption here

The reasons USDA gives for the rating, by the acres they affect. A component can carry several, so the acres overlap.

Slow water movement — 375,856 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Depth to bedrock — 334,500 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Flooding — 39,743 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Seepage, bottom layer — 38,058 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Depth to saturated zone — 31,361 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Slope — 17,192 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Filtering capacity — 2,542 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Ponding — 54 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.

Ratings by soil map unit

The largest map units in the county, each with its rating. A soil survey names the ground. The county's evaluation of your lot is what a permit turns on.

ALE — Aledo-Bolar association, 1 to 8 percent slopes — 98,161 acres in this county — rated Very limited. Dominant component: Aledo (50% of the map unit).
WoB2 — Windthorst fine sandy loam, 1 to 5 percent slopes, moderately eroded — 40,374 acres in this county — rated Very limited. Dominant component: Windthorst (85% of the map unit).
DwD — Duffau-Weatherford complex, 3 to 8 percent slopes — 28,685 acres in this county — rated Somewhat limited. Dominant component: Duffau (48% of the map unit).
BsE — Brackett-Maloterre complex, 2 to 12 percent slopes — 26,369 acres in this county — rated Very limited. Dominant component: Brackett (55% of the map unit).
DwC2 — Duffau-Windthorst complex, 1 to 5 percent slopes, moderately eroded — 24,416 acres in this county — rated Somewhat limited. Dominant component: Duffau (52% of the map unit).
VeC — Venus loam, 3 to 5 percent slopes — 22,776 acres in this county — rated Somewhat limited. Dominant component: Venus (90% of the map unit).
Yb — Santo and Bunyan soils, 0 to 1 percent slopes, frequently flooded — 19,475 acres in this county — rated Very limited. Dominant component: Santo (38% of the map unit).
ChC — Chaney loamy sand, 1 to 5 percent slopes — 16,381 acres in this county — rated Very limited. Dominant component: Chaney (85% of the map unit).

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-12

Sources

Each figure on this page has a government source and a checked-on date.

Parker County — Permitting · checked 2026-09-23
Parker County Order (2007) — Rules for On-Site Sewage Facilities, Section 10(A) · checked 2026-09-23
Parker County Permitting Department — Permitting Procedures for Your On-Site Sewage Facility · checked 2026-09-23
Texas Administrative Code, Title 30, Chapter 285, §285.91(12), Table II · checked 2026-09-23
USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-12

Verify before you act. Septic rules are set locally and they change. Check anything here before you spend money on it. Call the county environmental health office, on 817-598-6175.