Trenching is how water, sewer, electric, gas and drainage lines get from the street or the meter to a house, garage or shop. It's one of the most common jobs for residential excavators around Billings.
Common trenching jobs
- New or replacement water service from the curb stop to the house.
- Sewer lateral replacement when an old clay or Orangeburg line fails.
- Power and data to a detached garage, shop, barn or pole building.
- Septic lines and drain field trenches (with the required design and permit).
- Downspout and French drains to move water away from foundations.
- Gas lines for generators, shops and heaters (by licensed installers).
What it costs
Angi lists trenching for plumbing at about $1,500 to $10,000, depending on length, depth and access. Labor typically runs $120 to $150 per hour. Long runs through open ground are cheapest per foot. Crossing driveways, digging around trees and mature landscaping, rocky ground, and restoring lawns or pavement all add cost.
Call 811 first
Before any trench, the contractor files a locate request with Montana 811 (811). Utilities mark their lines with paint and flags, usually within a few business days. Private lines you own, such as a line to a shed or a sprinkler system, aren't marked by the utility, so tell the excavator where you know they run.
Depth
Each utility has its own depth requirement. Water lines must sit below frost depth to avoid freezing, and electrical conductors have minimum cover depths under the electrical code that vary by wiring method. Your plumber, electrician and local code set the specifics.
Trench safety rules
OSHA's trenching standard requires a protective system (sloping, benching, shoring or a trench box) for any trench 5 feet deep or more unless it's entirely in stable rock, and a competent person to inspect it. Trenches 20 feet or deeper need a system designed by a registered engineer. Spoil piles and equipment must stay at least 2 feet back from the edge. One cubic yard of soil can weigh as much as a car, which is why collapses are so dangerous.
Sewer lateral replacement
When a camera inspection shows a broken or root-filled sewer lateral, replacement means digging from the house to the main or to a cleanout. Many cities require a permit and inspection, and work in the street right-of-way may need traffic control and pavement restoration. Some lines can be replaced with trenchless methods (pipe bursting or lining) by specialist contractors, which saves landscaping.
Restoration
Ask whether the quote includes compacting backfill (so the trench doesn't settle), topsoil and seed, and pavement or sidewalk repair. Settled trenches are the most common complaint after utility work.
Septic systems
Outside public sewer areas, homes rely on septic systems, and their installation and repair is heavy excavation work: digging for the tank, distribution box and drain field trenches or beds. Septic work is regulated by state and local health departments, which usually require a soil evaluation, a designed system and inspections. Many excavating contractors are also licensed or certified septic installers; ask before you hire. A failing drain field may need replacement or a new area, which is why property owners should know where the reserve area is.
Running power and water to outbuildings
One of the most common residential trenching jobs is running power, water and data to a detached garage, shop or barn. Plan it once: lay conduit for power and a spare conduit for internet or future circuits, run the water line below frost depth, and put warning tape above lines in the trench. Mapping where everything was buried, with photos and measurements, saves trouble later. Keep electrical and water lines separated as required by code and your electrician.
Trenchless options
For crossing driveways, sidewalks or mature landscaping, directional boring can install pipe or conduit without an open trench. It costs more per foot than open trenching in clear ground but can be cheaper once you count restoration. Some excavators own boring rigs; others sub it out.
Working in the right-of-way
Water and sewer connections often run under the sidewalk, curb or street, which belongs to the city or county. Work there usually needs a right-of-way or street-cut permit, traffic control and pavement restoration to the owner's standards. Many cities require licensed plumbers for the connection itself and inspections before backfill.
Before you request quotes: a checklist
- What you're building or fixing, with any site plan, survey or building plans you have.
- Location and access. Gate widths, slopes, soft ground and overhead lines.
- Known buried lines you own, such as lines to sheds, sprinklers, septic tanks and propane lines, which 811 won't mark.
- Soil and water clues. Standing water, wet basements nearby, rock outcrops. The Web Soil Survey helps here.
- Where spoils go. Can extra dirt stay on site, or must it be hauled?
- Restoration. Topsoil, seed, sod or pavement repair expectations.
- Timeline, and the trades that follow the excavator.
- Photos of the work area from a few angles.
Excavation quotes vary more than most trades because so much depends on what's underground. Clear information up front narrows the range.
Serving Billings and nearby
We take requests from property owners across Billings and Yellowstone County, including Billings, Lockwood, Laurel, Shepherd, Huntley, Worden, Park City, Columbus, Joliet. Coverage depends on contractor availability; tell us your town or ZIP. Before any digging, your contractor contacts Montana 811 (811) to get buried utilities marked.
Common questions
How deep does a water line need to be?
Below the local frost depth, which your plumber and building department will specify. Northern states require more cover than southern ones.
Can I dig a trench myself?
Small, shallow trenches for low-voltage wiring are common DIY jobs, but you still must call 811 first. Anything deep, long or near utilities is safer with a professional.
How long does a utility trench take?
Short residential runs are often dug, inspected and backfilled in a day or two, depending on inspections and weather.
Will my lawn be ruined?
There will be a strip of disturbed ground. Good contractors separate topsoil, compact backfill and leave the area ready for seed or sod.
Do I need a plumber as well as an excavator?
For water and sewer connections, usually yes. Many jurisdictions require a licensed plumber for the connection and an inspection before backfill.