Trenching

• Water service installation: From meter to house, trenched below frost depth with proper pipe bedding
• Sewer & septic lines: Gravity flow requires precise slope (1-2% grade) and smooth trench bottom
• Electrical service: Conduit runs for underground power, meeting NEC depth and separation requirements
• Communications & data: Fiber optic, coax, and telephone lines trenched with warning tape and separation from power
• Gas lines: Steel or HDPE gas piping trenched with tracer wire and proper cover depth
• Irrigation & drainage: Mainlines, laterals, and drainage pipe with bedding and backfill to prevent settling
• Driveway crossings: Bore or trench under paved surfaces with casing pipe and controlled backfill

Utility locates come first. We call 811 at least two business days before digging and verify all private locates (propane, water, septic, irrigation). If records are incomplete, we use ground-penetrating radar or hand-dig test pits. No excavator touches dirt until we're confident utilities are marked.

Trench layout and depth control are critical. Water lines trench 36-48 inches below grade to stay below frost. Sewer lines follow engineered slope—typically 1% minimum—verified with laser levels. Electric conduit depth varies by voltage and location: 18 inches under driveways, 24 inches in open ground per NEC. We mark trench routes with paint and stakes before excavation begins.

Excavation width and safety: Trenches are cut 12-18 inches wider than pipe diameter to allow room for bedding and compaction. Depths over 4 feet require sloping, benching, or trench boxes per OSHA standards—we carry aluminum trench boxes and never allow unsafe entry. Spoil piles are placed away from trench edges to prevent cave-ins.

Bedding and backfill standards prevent future problems. Water and sewer lines get 4-6 inches of clean sand or pea gravel bedding below and around pipes. Electrical conduit is bedded in sand to prevent rock damage. Backfill is placed in 8-12 inch lifts and compacted with plate tampers or jumping jacks—critical under driveways and structures. Warning tape is placed 12 inches above buried utilities as required by code.

• Mini excavators (5-8 ton): Precision trenching in tight access areas with minimal ground disturbance
• Backhoes: Versatile machines for standard utility trenches and loading spoil
• Walk-behind trenchers: Fast, narrow cuts for fiber, irrigation, and shallow conduit runs
• Trench boxes: Aluminum shoring systems for safe entry on deep trenches (4+ feet)
• Laser levels: Grade verification for sewer and drainage trenches requiring slope accuracy
• Compaction equipment: Plate tampers, jumping jacks, and hand rollers for lift-by-lift backfill
• Bedding materials: Clean sand, pea gravel, or specified engineered fill per utility codes
• Warning tape: Color-coded detectable tape (blue = water, yellow = gas, red = electric, green = sewer)

All equipment is maintained daily and operators are trained in OSHA trench safety, utility damage prevention, and compaction standards.

• Utility strikes: Hitting power, gas, or fiber lines causes service outages, repair costs, and safety hazards
• Trench collapse: Unsafe trenches can injure or kill workers—OSHA violations carry heavy fines
• Frost heaving: Shallow water lines freeze and burst; trenching below frost depth is non-negotiable
• Settlement and cracking: Poor compaction causes driveways, sidewalks, and foundations to sink and crack
• Failed inspections: Wrong depth, missing bedding, or improper slope leads to re-excavation and delays

The Spokane, Newport, Coeur d'Alene, and Sandpoint region presents unique trenching challenges. Glacial till and cobble in Spokane and Kootenai counties require hydraulic hammers or rock saws to trench through hardpan layers. Sandy soils around Pend Oreille and Bonner counties trench easily but cave readily—trench boxes and rapid backfill are critical. High groundwater in low-lying areas requires dewatering pumps to keep trenches dry for pipe installation and inspection. Frost depth across the Inland Northwest ranges from 36 to 48 inches depending on elevation—we trench water lines at least 42 inches deep as a safety margin. Rocky slopes on mountain properties require switchback trenching or directional boring to avoid excessive excavation costs.

• Trenches excavated to specified depth and width per engineering plans and code requirements
• Proper bedding material (sand, gravel, or engineered fill) placed and compacted below and around utilities
• Backfill placed in lifts and compacted to 90-95% density to prevent future settlement
• Warning tape installed 12 inches above all buried utilities with correct color coding
• As-built documentation showing final trench depth, routing, and material quantities for permits and records
• Clean site with spoil removed or graded, and surface restored to near-original condition
• Coordination with utility installers, inspectors, and engineers for seamless project handoff