Excavation contractor jobsite in Washington County, RI

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Washington County, RI Contractor directory

Excavation contractors in Washington County, RI

23 verified excavating and site work contractors serving Washington County.

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County excavation guide

Ground conditions and project requirements in Washington County

Use this local research to understand soil, seasonal constraints, permits, and jobsite logistics before choosing a contractor.

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Soil Regime ProfileEPA Ecoregion 59, 84 (Northern Appalachian Piedmont, Boston Basin, Northeastern Coastal Zone)

Rhode Island Glacial Till Uplands & Narragansett Coastal Lowland

Dominant Soil Order: Spodosols / Inceptisols / Ultisols
Parent Material: Glacial Till and Stratified Drift over Narragansett Basin Pennsylvanian Coal-Measure Slate and Precambrian Granite Gneiss

Rhode Island is small but rock-and-clay complex. The Narragansett Basin (Providence, Fall River side) sits on Pennsylvanian coal-measure slate, shale and conglomerate: till over soft-to-hard sedimentary rock, historic coal-mine and mill-foundation legacies in the urban core, and marine clay in the harbor lowlands (the same Presumpscot-age estuarine clay as coastal Massachusetts). The uplands (Kent, Washington counties) are glacial till over Narragansett granite gneiss and Esmond diorite: thin stony soils, bedrock ledges, boulders, and slopes 15-40 percent. Stratified drift aquifers run through the Pawtuxet and Wood-Pawcatuck valleys: clean sand and gravel, fast percolation, trench-stability issues, and aquifer-protection overlays that shape septic design. Hydric soils run 20-35 percent in the coastal lowlands and the Great Swamp. Shrink-swell is negligible. Frost runs 36-42 inches.

Geographic Footprint:Rhode Island's counties (Providence, Warwick, Newport) are glaciated till over slate-and-granite: boulders and ledges in the uplands, Narragansett Basin slate and legacy-mill ground in the urban core, clean stratified drift in the valleys, and coastal marine clay. Frost runs 36-42 inches.
Geotechnical Baseline

Physical Ground Conditions & Soil Properties

Shallow Bedrock (<50 in)
19.4%of county land area

Moderate rock encounters along ridges and upper slope shoulders.

High Shrink-Swell Clay
12.0%expansive soil

Moderate shrink-swell; verify plasticity index on structural fill.

Median Water Table Depth
19inches from surface

Shallow water table; active dewatering or sumps needed for deep trenching.

Hydric / Wetland Soils
18.9%hydric coverage

Indicates poor natural drainage and potential jurisdictional wetland pockets.

Steep Terrain (Slope >15%)
4.4%of terrain

Predominantly gentle to rolling slopes suitable for wheeled earthmoving.

Septic Severe Limitations
72.6%severe rate

High rate of conventional drainfield limitations; engineered or drip systems often required.

Dominant Soil Textures:Fine sandy loamSilt loamSandy loam
Surface Stones / Boulders: 17.4% coverage
Compliance & Permitting

Earthwork Regulations & Permit Thresholds

Stormwater & Erosion Control
RIPDES Construction General Permit (RIDEM; 2025 CGP in effect to Sept 26 2026, reissuance expected); coverage for sites disturbing one acre or more or part of larger common plan

Administers NPDES stormwater discharge coverage for land-disturbing construction activities.

State Threshold:1.00 Acre
Local Threshold:Follows state
Onsite Wastewater & Utilities
RIDEM Office of Water Resources

Jurisdiction over septic tank permits, soil evaluation perk tests, and drainfield sizing.

Housing on Septic:35.0%
Soil Evaluation:Soil evaluation form filed with RIDEM Director before OWTS application and within 90 days of test; 24-hour notice of test; DEM-licensed designer
811 One-Call Requirements
Dig Safe (811)

Mandatory notice window: 72 hours prior to mechanized earthwork (excluding weekends and legal holidays).

Licensing & Clearing Permits
Weather & Ecology

Seasonal Constraints & Clearing Windows

Frozen Ground Days
0days / year

Typical days with sub-freezing soil conditions affecting digging.

Wet Season Months
March

Peak precipitation window requiring sediment traps and soil aeration.

Supply Chain & Hazards

Logistics, Aggregate Sources & Geohazards

Aggregate & Material Supply
Sand & Gravel Operation

Nearest active quarry: 4.7 miles haul distance.(52 active crushed stone/sand operations within 50 miles).

Flood & Hazard Overlay
FEMA 100-Yr Flood:15.8%(100% NFHL digital map coverage)
NWI Wetlands:49.0%jurisdictional coverage
Karst Terrain & Sinkhole Risk: Low

0.0% of county underlain by soluble carbonate rock formations.

HUC8 Primary Watersheds:Point Judith-Block Island, Narragansett, Pawcatuck River
Public conservation land: 47.8% (USGS PAD-US).

Area-specific FAQ

Do I need to call before digging in Washington County?

Yes. You should contact Rhode Island 811 at least 2 working days before any digging so underground lines can be marked.

How deep do footings need to be in Rhode Island?

In Rhode Island, footings typically need to extend below the frost line, which is around 36 inches here. A local contractor will confirm the code requirement for your site.

Verified local listings

Excavation contractors serving Washington County

23 verified listings (showing first 20)

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