USA 811 — call before you dig
Every trench in California starts with a USA 811 ticket. The call is free, the marking is free, and the law requires it. Underground service alert marks gas, electric, water, sewer, communications, and other regulated utilities so we know where to dig and where to hand-pothole. Skipping this step is how trenches hit gas lines and electrical service. We do not break ground until the locate is on the property and the marks are fresh.
Common utility trenches
- Water service line — from the meter to the house or new structure
- Sewer lateral — from the structure to the public main or septic lateral
- Electrical service trench — underground feeder from the transformer or service pedestal
- Gas service trench — from the meter to the structure (gas company sets the meter; we trench)
- Irrigation trenching — main line, valves, and lateral runs across landscape zones
- Fiber and low-voltage conduit — internet, security, and communications runs
- ADU utility trench — usually a multi-utility trench from the main house to the ADU
Depth and bedding
| Utility | Typical Depth (Sacramento region) | Bedding Notes |
|---|---|---|
| Water service | 18-30 in | Sand bedding, tracer wire on plastic pipe |
| Sewer lateral | 24-48 in (slope-driven) | Sand or rock bedding, slope critical |
| Electrical service (PG&E spec) | 24-36 in conduit | Sand bedding, warning tape, conduit per utility spec |
| Gas service (PG&E spec) | 18-30 in | Sand bedding, warning tape, gas-company spec |
| Irrigation main | 12-18 in | Native backfill usually OK |
| Fiber/low-voltage conduit | 12-24 in | Sand bedding, marker tape |
Trench safety
Trenches deeper than 4 feet in California require employee-protection systems (shoring, sloping, shielding) under Cal/OSHA. We respect that boundary. Most residential service trenches stay shallow enough not to need a trench box, but sewer laterals on sloped lots, ADU feeders, and any trench that goes vertical past 4 feet need engineered protection. We do not work in unprotected trenches.
Coordination with the licensed contractor
We dig the trench, bed it correctly for the utility type, and backfill after the licensed plumber, electrician, gas-fitter, or utility provider does the tie-in. We do not pull electrical permits, we do not splice gas lines, and we do not tie sewer laterals — those are the licensed trades' work. We coordinate timing so the licensed contractor arrives when the trench is open and ready, and we backfill immediately after their inspection so the trench is not open longer than it needs to be.
What affects price
- Length of the trench
- Depth (deeper trenches need more spoil management and possibly shoring)
- Soil type (clay vs decomposed granite vs rock)
- Access for the trencher or mini-excavator
- Surface restoration scope (cut concrete, restore asphalt, replace sod)
- Bedding material (sand vs rock vs native)
- Coordination with the licensed utility contractor's schedule
Frequently asked questions
- Do I need to call USA 811 before trenching?
- Yes. California law requires the USA 811 underground service alert before any excavation. We will not break ground until the ticket is on the property and the utilities are marked.
- Do you tie in the utility too?
- No. We excavate the trench, bed it correctly, and backfill. The licensed plumber, electrician, gas-fitter, or utility provider does the tie-in. Keeping scope clean keeps the permit chain straight.
- How deep should my utility trench be?
- It depends on the utility. Water service is typically 18-30 inches. Sewer laterals run 24-48 inches depending on slope. Electrical and gas conduit follow the utility's published spec. We confirm depth from the spec for your project before we dig.
- How much does utility trenching cost?
- A short single-utility trench (under 50 ft) on accessible ground often runs $1,500-$3,500. ADU multi-utility trenches commonly run $4,000-$10,000+ depending on length, depth, surface restoration, and coordination scope.
- Do you handle the trench for an ADU?
- Yes. ADU trenching is one of our most common scopes — water, sewer, electrical, and sometimes gas in a single coordinated trench from the main service to the new structure.
Related planning resources
Trenching service
Full trenching scope for water, sewer, electrical, gas, and irrigation.
Excavation service
Broader excavation work when the trench is part of a larger site scope.
Site preparation service
Coordinate trenching with the larger site-prep sequence.
ADU pad preparation guide
Trenching is a standard step in ADU site prep.
Backyard leveling
Surface restoration and regrade after the trench is closed.
Concrete slab removal
When the trench has to cross an existing slab or driveway.