Underground utility trenching for gas, electrical, or fiber optic lines typically costs $8 to $30 per linear foot depending on depth, conduit type, and what the trench crosses along its route. Treat every figure on this page as a starting point rather than a quote: locating existing underground utilities before digging is not optional anywhere in North America, and this single step affects both project timeline and safety more than any other factor on this list.
Before any utility trenching begins, existing underground lines in the area have to be located and marked through the applicable regional utility locate service, since digging into an existing gas, electrical, or communication line is a genuine safety hazard and typically a legal requirement to avoid, not just best practice.
What actually drives the price
Utility type sets specific depth and separation requirements. Gas lines, electrical conduit, and fiber or communication lines each have different minimum burial depths and required separation distances from each other and from other utilities, set by code, which directly affects trench depth and, where multiple utilities are being installed together, trench width and layout.
What the trench crosses along its route matters significantly. Crossing a driveway, existing landscaping, or other utility lines adds complexity, and crossing under a paved surface sometimes calls for directional boring instead of open trenching to avoid disturbing the surface.
Conduit and bedding requirements vary by utility type and local code, with some jurisdictions requiring specific conduit material or a marked warning tape buried above the line so future excavation work is alerted to its presence before digging deeper.
Soil and rock conditions affect trenching difficulty the same way they do on any underground utility work, and rock encountered along the planned route sometimes requires different equipment or a route adjustment.
Coordination with the utility provider
Trenching for a new utility connection is typically coordinated with the utility provider, who often has specific requirements for trench dimensions, conduit type, and inspection before the line is energized or connected. Confirm these requirements before trenching begins, since work not meeting the utility's standard sometimes has to be redone.
A short checklist before you book
Confirm underground utility locates are completed before any digging starts. Confirm required depth and separation distances for your specific utility type. Map the full trench route and flag any surfaces or existing utilities it crosses. Confirm conduit and bedding requirements with the utility provider or local code. Confirm inspection requirements before the trench is backfilled.
Costs vary by site conditions. Use the ranges here to sanity-check what you're quoted, then get a direct price for your own property.
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