Soil and perc tests in St. Johns County, Florida

What is a perc test and does St. Johns County require one?

Required

A soil evaluation must occur before the department issues a permit.

Florida Administrative Code, Rule 62-6.030, Fees · checked 2026-09-23

How USDA rates the ground in St. Johns County

Very limited across most of the county — 99.9% of the rated acres. A rating describes the ground, not a parcel. The county's site evaluation decides each lot.

• Very limited — 388,481 acres — 99.9% of 388,786 rated acres.
• Somewhat limited — 305 acres — 0.1% of 388,786 rated acres.
• Not rated — 41,614 acres, excluded from the denominator — mostly urban land and water.

99.9% of 388,786 rated acres. 41,614 acres unrated. Survey area FL109 version 24, established 2025-08-28.

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-23

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.

• Depth to saturated zone — 380,932 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Seepage, bottom layer — 320,968 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Slow water movement — 222,025 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Flooding — 98,426 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Filtering capacity — 72,620 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Ponding — 38,764 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Subsidence — 19,580 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Slope — 1,714 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to cemented pan — 198 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
• Depth to bedrock — 45 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.

• 3 — Myakka-Myakka, wet, fine sands, 0 to 2 percent slopes — 39,870 acres in this county — rated Very limited. Dominant component: Myakka (70% of the map unit).
• 99 — Water — 34,220 acres in this county — rated Not rated. Dominant component: Water (100% of the map unit).
• 9 — Pomona fine sand — 32,020 acres in this county — rated Very limited. Dominant component: Pomona (70% of the map unit).
• 36 — Riviera fine sand, frequently flooded — 26,530 acres in this county — rated Very limited. Dominant component: Riviera (85% of the map unit).
• 34 — Tocoi fine sand — 20,575 acres in this county — rated Very limited. Dominant component: Tocoi (65% of the map unit).
• 7 — Immokalee fine sand — 20,230 acres in this county — rated Very limited. Dominant component: Immokalee (70% of the map unit).
• 24 — Pellicer silty clay loam, frequently flooded — 17,135 acres in this county — rated Very limited. Dominant component: Pellicer (90% of the map unit).
• 46 — Holopaw fine sand — 16,800 acres in this county — rated Very limited. Dominant component: Holopaw (70% of the map unit).

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-23

Sources

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

1. Florida Department of Health in St. Johns County — Environmental Health · checked 2026-09-23
2. Florida Department of Health in St. Johns County — Main Office · checked 2026-09-23
3. St. Johns County 2050 Comprehensive Plan, Infrastructure Element, Policy D.1.4.7 · checked 2026-09-23
4. Florida Administrative Code, Rule 62-6.030, Fees · checked 2026-09-23
5. USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-23

Related pages

• Septic rules and requirements in St. Johns County, Florida
• Septic permits and fees in St. Johns County, Florida
• Septic rules and requirements in Florida
• Septic rules in St. Johns County