Soil and perc tests in Guadalupe County, Texas

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

Yes. A registered sanitarian, a site evaluator or an engineer must do a site and soil evaluation first.

The evaluation covers the whole lot and the soil where the system will go.

Guadalupe County Environmental Health, OSSF Permit Process · checked 2026-10-06

How USDA rates the ground in Guadalupe County

Very limited across most of the county — 95.2% of the rated acres. A rating describes the ground, not a parcel. The county's site evaluation decides each lot.

• Very limited — 364,423 acres — 95.2% of 382,690 rated acres.
• Somewhat limited — 18,267 acres — 4.8% of 382,690 rated acres.
• Not rated — 74,948 acres, excluded from the denominator — mostly urban land and water.

95.2% of 382,690 rated acres. 74,948 acres unrated. Survey area TX187 version 22, established 2026-09-03.

USDA NRCS Soil Data Access (SSURGO) · checked 2026-10-06

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 — 350,490 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to bedrock — 72,758 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to saturated zone — 63,958 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Flooding — 37,231 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Seepage, bottom layer — 21,696 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Filtering capacity — 20,435 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Slope — 14,441 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to cemented pan — 9,113 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Large stones — 1,260 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.

• PaD — Patilo and Arenosa soils, 1 to 8 percent slopes — 53,311 acres in this county — rated Very limited. Dominant component: Patilo (49% of the map unit).
• BrA — Branyon clay, 0 to 1 percent slopes — 45,020 acres in this county — rated Very limited. Dominant component: Branyon (85% of the map unit).
• HoB — Houston Black clay, 1 to 3 percent slopes — 40,190 acres in this county — rated Very limited. Dominant component: Houston Black (80% of the map unit).
• CsC3 — Crockett loam, 2 to 5 percent slopes, eroded — 32,615 acres in this county — rated Very limited. Dominant component: Crockett (85% of the map unit).
• DmC — Robco-Tanglewood complex, 1 to 5 percent slopes — 32,025 acres in this county — rated Very limited. Dominant component: Robco (46% of the map unit).
• WdC3 — Windthorst fine sandy loam, 1 to 5 percent slopes, eroded — 20,042 acres in this county — rated Very limited. Dominant component: Windthorst (85% of the map unit).
• CfB — Crockett fine sandy loam, 1 to 3 percent slopes — 18,910 acres in this county — rated Very limited. Dominant component: Crockett (85% of the map unit).
• HeC3 — Heiden clay, 3 to 5 percent slopes, eroded — 15,068 acres in this county — rated Very limited. Dominant component: Heiden (85% of the map unit).

USDA NRCS Soil Data Access (SSURGO) · checked 2026-10-06

Sources

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

1. Guadalupe County Environmental Health · checked 2026-10-06
2. Guadalupe County Environmental Health, OSSF page · checked 2026-10-06
3. Guadalupe County Environmental Health, OSSF FAQ · checked 2026-10-06
4. Guadalupe County On-Site Sewage Facilities Order, Section 10(D) · checked 2026-10-06
5. Guadalupe County Environmental Health Fee Schedule · checked 2026-10-06
6. Guadalupe County Environmental Health, OSSF Permit Process · checked 2026-10-06
7. 30 TAC §285.91(2), Table II -- Septic Tank and Aerobic Treatment Unit Sizing · checked 2026-09-23
8. USDA NRCS Soil Data Access (SSURGO) · checked 2026-10-06

Related pages

• Septic rules and requirements in Guadalupe County, Texas
• Septic permits and fees in Guadalupe County, Texas
• Septic rules and requirements in Texas
• Septic rules in Guadalupe County