Washington County is the second-densest county in Oregon and the technology corridor of the Portland metro. Hillsboro sits at the county seat, with Beaverton, Tigard, Tualatin, Sherwood, and Forest Grove filling out the commercial footprint. The Intel campus complex and the surrounding semiconductor supply chain drive a meaningful share of the county's industrial construction volume -- and the spillover into commercial pad-prep, parking-lot work, and utility-trench upgrades keeps excavation crews busy year round. Add Willamette Valley clay subgrade and a heavy permit-and-stormwater regime tied to the Tualatin Basin watershed, and Washington County excavation work has its own playbook.
Cojo Excavation & Asphalt covers Washington County work out of our I-5 corridor operations. This guide walks through what west-metro conditions mean for site-prep cost, the project mix typical in the area, and what to look for in a CCB-licensed excavation contractor that handles permit-heavy urban work.
Hillsboro and the Intel Corridor
Hillsboro has roughly 110,000 residents and sits at the heart of Oregon's semiconductor industry. The Intel Ronler Acres, Aloha, and Jones Farm campuses together cover thousands of acres and have been in near-continuous build-and-renovation cycles for decades. The supply chain that surrounds Intel -- equipment vendors, fabrication and assembly suppliers, gas-and-chemical handlers -- has produced its own ecosystem of commercial and light-industrial sites along Cornell Road, the 26 corridor, and the Hillsboro Airport area.
Excavation work tied to the Intel corridor leans toward larger commercial pads with strict finish-grade tolerances, heavy utility-trench mainlines, and stormwater detention sized for industrial-scale runoff. Most of the high-end Intel-direct work is bid by large regional contractors, but secondary commercial scopes -- support facilities, contractor parking, smaller pads -- are mid-sized contractor territory. See our driveway excavation in Hillsboro work for the residential side.
Beaverton, Tigard, Tualatin -- The Retail and Office Corridor
South and east of Hillsboro, Beaverton, Tigard, Tualatin, and Sherwood form the densest retail and office footprint in Washington County. The Beaverton-Hillsdale Highway corridor, Highway 217, the I-5 frontage near Tualatin, and the Tigard Triangle all carry steady commercial pad-prep and utility-trench volume. Tualatin and Sherwood mix in distribution-warehouse work and food-and-beverage manufacturing pads.
Subgrade across this corridor is classic Willamette Valley clay loam. Most commercial pads here need 6 to 8 inches of compacted crushed-rock base over scarified subgrade, with perimeter drainage tied to municipal stormwater systems or Clean Water Services infrastructure. For surface work that follows the dirt, asphalt paving services in Washington County, Washington County parking lot striping, and concrete curbing services in Washington County are common sequel scopes.
Forest Grove, Cornelius, Banks -- West County
West of Hillsboro along Highway 8, Forest Grove and Cornelius sit at the edge of the Tualatin Basin. Banks and Gaston further west and southwest are smaller rural-residential and agricultural communities. Excavation work here is a mix of commercial pad work in the Forest Grove core, residential and small-commercial work in Cornelius, and rural driveway, septic, and farm-shop pads in the more outlying communities.
Subgrade in the western part of the county shifts toward clay-on-bedrock conditions as you climb into the Coast Range foothills. Rock-hammer time becomes a real factor on hillside cuts and deeper trenches in Banks and the Gales Creek corridor.
Clean Water Services and Stormwater Code
Washington County's stormwater regime is administered through Clean Water Services across most of the urban footprint. The practical implication for excavation contractors: any project that creates new impervious surface or significantly alters drainage triggers a stormwater submittal that has to align with the dirt work happening on site.
For excavation scopes this typically means:
- Coordinating the cut-and-fill plan with the stormwater design from day one.
- Building infiltration features, biofiltration swales, or detention basins into the excavation work.
- Sequencing erosion-control measures before stripping begins.
- Working within Tualatin Basin watershed-protection rules where buffers and setbacks apply.
Contractors who treat Clean Water Services rules as paperwork tend to leave money and time on the table. Treating them as a constraint that shapes the dig plan from the start is faster overall.
Wet-Season Strategy
The west metro gets roughly 38 to 45 inches of rain a year, concentrated mid-October through April. Pure dry-method excavation on clay subgrades typically pauses December through February in average years. What can still move:
- Utility-trench work in the urban core with dewatering and gravel backfill.
- Storm-drain and infiltration-feature installation, often easier in wet weather.
- Same-week footing excavation paired with covered pour staging.
Peak booking window is May through October. Competent west-metro crews are back-to-back from June through September -- February is the right time to lock dates for a July dig.
Common Washington County Project Types
The mix we see across the county:
- Hillsboro / Beaverton residential driveway, 400 to 1,200 sq ft, valley clay: Strip 8 to 12 inches, crushed-rock base, drainage tied to Clean Water Services-approved features.
- Tigard / Tualatin commercial pad, 5,000 to 30,000 sq ft: Strip topsoil, base prep, stormwater feature integration, traffic-control plan.
- Intel corridor support facility pad: Tighter finish-grade tolerance, heavier base spec for industrial truck traffic.
- Forest Grove / Cornelius small-commercial pad: Lower right-of-way overhead, different stormwater path than urban-Hillsboro work.
- Utility-trench replacement, 100 to 500 linear feet: Locate, saw-cut, trench, bedding, pipe, compact backfill, surface restoration per right-of-way permit.
Washington County Excavation Cost Ranges
Washington County pricing reflects high permit overhead, traffic-control costs on commercial work, Clean Water Services infrastructure requirements, and the highest labor cost outside of Portland city limits.
Industry Baseline Range
| Project Type | Typical Range |
|---|---|
| Residential driveway excavation (400 to 1,200 sq ft) | $4,500 to $12,000 |
| Commercial pad prep, per square foot | $5 to $16 |
| Industrial pad (Intel corridor support) | $30,000 to $250,000+ |
| Utility trench, per linear foot | $35 to $110 |
| Stormwater infiltration or detention feature | $1,500 to $6,500+ |
| Spoils haul-off, per cubic yard | $55 to $110 |
| Traffic-control package, per day | $750 to $2,200 |
Current Market Reality
2026 Washington County pricing lands in the upper-middle to upper end of these ranges. Permit-and-stormwater overhead has climbed steadily, traffic-control crew rates have outpaced general construction inflation, and labor for operators experienced in Clean Water Services compliance is in tight supply. Quotes well below the lower bound usually skip line items that will appear on a change order mid-project.
Booking a Washington County Site Walk
Cojo Excavation & Asphalt covers Hillsboro, Beaverton, Tigard, Tualatin, Sherwood, Forest Grove, Cornelius, Banks, and the rest of Washington County. We do site walks before we quote, and our scope sheet names soil type, drainage handling, stormwater feature integration, base-rock volume, traffic-control overhead, and permit path. Contact our west-metro crew to schedule a walk-through. For the broader range of what we do across Oregon, the excavation services page covers our crew, equipment, and licensing.