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Trenching / Underground project guide

Trenching / Underground contractors cost and hiring guide

Water, sewer, gas, electric, irrigation and drainage lines put in the ground to spec, with 811 locates, shoring and bedding handled right.

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Key facts

Trenching / Underground numbers you can check

Rules and figures that come up in nearly every trenching / underground quote, with the public source for each one.

FactWhat it saysSource
Trench protective systemTrenches 5 feet or deeper require shoring, a trench box or sloped walls under OSHA 1926.652.OSHA, Excavations (29 CFR 1926.652)As of September 2026
Spoils setbackExcavated soil and equipment must be kept at least 2 feet from the trench edge.OSHA, Specific Excavation Requirements (29 CFR 1926.651)As of September 2026
Ladder accessA safe way out (ladder, stairway or ramp) must be within 25 feet of workers in any trench 4 feet or deeper.OSHA, Specific Excavation Requirements (29 CFR 1926.651)As of September 2026
811 locates811 locates are free and required before any digging; notice periods run about 2 working days in most states.Common Ground Alliance, 811 Before You DigAs of September 2026

Project guide

Hiring trenching / underground contractors

Trenching and underground utility contractors open the ground for pipe and conduit, bed and backfill it, and put the surface back. What looks like a straight line on a plan is governed by a few hard numbers: 811 locates before any digging, a minimum cover depth that varies by utility (commonly 18 to 24 inches for electric and gas service, and below the frost line for water), and OSHA's requirement that any trench five feet or deeper have a protective system such as a trench box, shoring or a sloped wall, with a competent person on site. Bedding material under the pipe, compaction of the backfill in lifts and tracer wire on non-metallic pipe are the details that separate a line that lasts fifty years from one that settles and cracks the driveway above it.

GradeLine lists 3,794 trenching / underground contractors.Compare their work and equipment, then confirm availability and service area before requesting a quote.

Listed businesses are based in Fountain Hills, Tucson, Anson, White Mountain Lake, San Antonio, West Palm Beach, though most crews travel well beyond their home city.

What trenching / underground work costs

Simple trenching in soft soil is often priced per linear foot, roughly $4 to $12 for shallow runs and $10 to $30 or more when depth, rock or shoring come into play. A residential water or sewer service replacement typically runs $3,000 to $12,000 depending on length, depth and how much pavement has to be cut. Directional boring under driveways and roads is priced separately, often $10 to $30 per foot.

Ranges are national and approximate; regional labor rates, material prices and site conditions move them in both directions.

Common projects

  • Water, sewer and gas service lines from the main to the house, including tie-ins and taps
  • Electrical, telecom and fiber conduit runs, plus direct-burial cable trenches
  • French drains, storm laterals, culverts and irrigation mains

What affects a quote

  • Trench length, depth and width, and whether the route crosses pavement, tree roots or other utilities
  • Soil, rock and groundwater, which decide whether a trencher, an excavator or dewatering is needed, and whether shoring is required
  • Bedding stone, compacted backfill, pipe material, and restoration of grass, gravel or concrete over the top

Trenching / Underground FAQ

What does trenching / underground work cost?

Simple trenching in soft soil is often priced per linear foot, roughly $4 to $12 for shallow runs and $10 to $30 or more when depth, rock or shoring come into play. A residential water or sewer service replacement typically runs $3,000 to $12,000 depending on length, depth and how much pavement has to be cut. Directional boring under driveways and roads is priced separately, often $10 to $30 per foot.

What should I share when requesting a trenching / underground estimate?

Send the route on a plot plan, the pipe or conduit size, the connection points at both ends, target depth if the utility has told you one, and how you want the surface restored.

What can change the cost of trenching / underground work?

The main cost items are trench length, depth and width, and whether the route crosses pavement, tree roots or other utilities; soil, rock and groundwater, which decide whether a trencher, an excavator or dewatering is needed, and whether shoring is required; bedding stone, compacted backfill, pipe material, and restoration of grass, gravel or concrete over the top. A site visit helps the crew see which ones apply.

Do trenching / underground projects need permits?

Utility work in the public right-of-way needs a road opening permit and often a bond. Sewer, water and gas connections require plumbing or utility permits with an open-trench inspection, and gas lines must be pressure tested before backfill. 811 is required by law in every state and locates are free.

Find trenching / underground contractors near you

Pick a state to see the trenching / underground contractors listed there. Most crews travel well beyond their home city, so confirm the service area before requesting a quote.

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