Power to a shop, water to a barn, conduit to a gate opener, a line out to the well. Trenching is straightforward work when it is done to depth, bedded properly and located before the first bucket goes in the ground. It gets expensive fast when it is not.
What we trench for
- Electrical service and sub-panel feeds to shops and outbuildings
- Water lines to barns, shops, hydrants and stock tanks
- Conduit for gates, lighting, cameras and irrigation control
- Gas line trenches for your licensed gas fitter
- Sleeving under driveways and walkways
- Drain and downspout lines
We call 811 before we dig, every time
Washington law requires an excavation notice no less than two and no more than ten business days before work starts, and the dig area has to be white-lined before locates are requested. It is free to the excavator and it is not optional. We handle the call and the marking as part of the job.
As of 1 January 2026, an excavator may not break ground until every utility operator with facilities in the area has responded. Enforcement got sharper in July 2025 too — damaging a gas or hazardous liquid pipeline now carries civil penalties up to twenty five thousand dollars. So no utility trench can start the day you call, whoever you hire. Build two to ten business days into your timeline.
Depth, bedding and the details that matter
Trench depth is set by what is going in it and by your inspector. Buried electrical, water and communications all have different requirements, and a water line has to sit below frost. In the City of Spokane, footings go 24 inches below finished grade for frost, and water lines are deeper still.
We bed lines in sand or screened material where the native ground is rocky, which most of the ground north and east of Spokane is. Glacial till full of fist-sized rock will chew through poly pipe and nick conduit if you drop the line straight onto it and backfill. Then we compact in lifts so the trench line does not sink over the first winter.
We leave the trench open for your inspection and come back to close it once it passes. Your electrician or plumber makes the connections under their own permit — we dig it, bed it and put it back.
Related work
Trenches get closed properly with backfilling. For sewer and water service specifically, see sewer and water line digs, and for irrigation mainlines see sprinkler and irrigation repair.
Where we work
Spokane, Spokane Valley, Liberty Lake, Mead, Colbert, Chattaroy, Deer Park, Nine Mile Falls, Cheney, Airway Heights and Medical Lake — about 50 miles out from Spokane. We work the Washington side of the state line.
Grizzly Excavation Services LLC — Washington contractor license GRIZZES767J5. Licensed, bonded and insured. Free estimates.