Soil and perc tests in Bell County, Texas

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

Yes. Texas requires a site evaluation before it issues a permit.

A site evaluator or an engineer checks the soil in two pits or borings. The evaluator also checks for shallow groundwater and reviews slope and flood risk. The county uses this report to set the system's size.

Texas Administrative Code, Title 30, Chapter 285, Section 285.30, Site Evaluation · checked 2026-09-23

How USDA rates the ground in Bell County

Very limited across most of the county — 93.0% of the rated acres. A rating describes the ground, not a parcel. The county's site evaluation decides each lot.

• Very limited — 532,556 acres — 93.0% of 572,412 rated acres.
• Somewhat limited — 39,856 acres — 7.0% of 572,412 rated acres.
• Not rated — 122,935 acres, excluded from the denominator — mostly urban land and water.

93.0% of 572,412 rated acres. 122,935 acres unrated. Survey area TX027 version 25, 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 — 389,383 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to bedrock — 338,198 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Flooding — 57,172 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Large stones — 35,719 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Slope — 35,510 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to cemented pan — 10,221 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to saturated zone — 9,469 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Seepage, bottom layer — 9,430 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Filtering capacity — 3,702 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Ponding — 194 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.

• HoB — Houston Black clay, 1 to 3 percent slopes — 55,019 acres in this county — rated Very limited. Dominant component: Houston Black (80% of the map unit).
• DeB — Denton silty clay, 1 to 3 percent slopes — 37,126 acres in this county — rated Somewhat limited. Dominant component: Denton (85% of the map unit).
• SPD — Speck association, 1 to 8 percent slopes — 34,862 acres in this county — rated Very limited. Dominant component: Speck (82% of the map unit).
• HeB — Heiden clay, 1 to 3 percent slopes — 26,285 acres in this county — rated Very limited. Dominant component: Heiden (85% of the map unit).
• PrB — Purves silty clay, 1 to 4 percent slopes — 25,936 acres in this county — rated Very limited. Dominant component: Purves (88% of the map unit).
• EcPD — Eckrant-Purves association, 1 to 8 percent slopes — 24,779 acres in this county — rated Very limited. Dominant component: Eckrant (65% of the map unit).
• TnA — Tinn clay, 0 to 1 percent slopes, frequently flooded — 21,879 acres in this county — rated Very limited. Dominant component: Tinn (85% of the map unit).
• ErB — Eckrant-Rock outcrop complex, 1 to 8 percent slopes, extremely stony — 21,374 acres in this county — rated Very limited. Dominant component: Eckrant (60% 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. Bell County Public Health District · checked 2026-10-06
2. Bell County Public Health District, OSSF Process · checked 2026-10-06
3. Bell County Public Health District, Additional Rules beyond Chapter 285 · checked 2026-10-06
4. Bell County Public Health District, On-Site Sewage Fees · checked 2026-10-06
5. Texas Administrative Code, Title 30, Chapter 285, Section 285.30, Site Evaluation · checked 2026-09-23
6. USDA NRCS Soil Data Access (SSURGO) · checked 2026-10-06

Related pages

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