Soil and perc tests in Ulster County, New York

USDA rates most of the soil in Ulster County Very limited for septic absorption fields — 100.0% of the rated acres. The county calls this test a percolation test. It runs at the drainfield site. USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-13

Very limited

USDA rating, 100.0% of rated acres

checked 2026-09-13

Slope

Most common limiting reason

checked 2026-09-13

Yes

Site evaluation required

checked 2026-09-23

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

Yes. The county calls this test a percolation test. It runs at the drainfield site.

The county checks the soil first, with a test pit. Then it runs the percolation test.

Ulster County Department of Health — Sewage Disposal System Application · checked 2026-09-23

How USDA rates the ground in Ulster County

Very limited across most of the county — 100.0% of the rated acres. A rating describes the ground, not a parcel. The county's site evaluation decides each lot.

Very limited — 624,740 acres — 100.0% of 624,740 rated acres.
Not rated — 118,560 acres, excluded from the denominator — mostly urban land and water.

100.0% of 624,740 rated acres. 118,560 acres unrated. Survey area NY111 version 24, established 2025-09-02.

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-13

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.

Slope — 402,480 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Depth to bedrock — 313,832 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Slow water movement — 292,396 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Depth to saturated zone — 273,708 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Large stones — 95,093 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Seepage, bottom layer — 81,519 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Depth to cemented pan — 40,790 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Ponding — 37,229 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Filtering capacity — 33,109 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Flooding — 16,650 acres. Reasons overlap — a component can carry several — so these acres exceed rated acres.
Subsidence — 6,727 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.

ARF — Arnot-Oquaga-Rock outcrop complex, very steep — 93,770 acres in this county — rated Very limited. Dominant component: Arnot (40% of the map unit).
ORD — Oquaga-Arnot-Rock outcrop complex, moderately steep — 50,545 acres in this county — rated Very limited. Dominant component: Oquaga (35% of the map unit).
LOC — Lordstown-Arnot-Rock outcrop complex, sloping — 45,162 acres in this county — rated Very limited. Dominant component: Lordstown (35% of the map unit).
WLB — Wellsboro and Wurtsboro soils, gently sloping, very bouldery — 31,847 acres in this county — rated Very limited. Dominant component: Wellsboro (41% of the map unit).
BOD — Bath-Nassau-Rock outcrop complex, hilly — 28,888 acres in this county — rated Very limited. Dominant component: Bath (40% of the map unit).
RXF — Rock outcrop-Arnot complex, 25 to 70 percent slopes — 28,724 acres in this county — rated Not rated. Dominant component: Rock outcrop (55% of the map unit).
LCD — Lackawanna and Swartswood soils, moderately steep, very bouldery — 24,795 acres in this county — rated Very limited. Dominant component: Lackawanna (41% of the map unit).
W — Water — 24,494 acres in this county — rated Not rated. Dominant component: Water (100% of the map unit).

USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-13

Sources

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

Ulster County Department of Health — Sewage Disposal System Application · checked 2026-09-23
Ulster County Department of Health — Environmental Health Division · checked 2026-09-23
Ulster County Sanitary Code, Article VI §6.4.6 and §6.4.13 · checked 2026-09-23
Ulster County Department of Health — Application for and Report of Sewage Disposal System · checked 2026-09-23
USDA NRCS Soil Data Access (SSURGO) · checked 2026-09-13

Verify before you act. Septic rules are set locally and they change. Check anything here before you spend money on it. Call the Ulster County Department of Health, Environmental Health Services Division, on 845-340-3010.