What Types of Trenching Do We Handle?
Trenching creates the linear cuts needed to run buried utilities, pipes, conduit, and drainage systems. The trench profile — width, depth, and bottom preparation — is determined by what's being installed and what the relevant trade or engineer specifies. We cut and backfill; the utility contractor installs the pipe or conduit.
- Utility trenching — electric, gas, water, and sewer service runs from the street or main to the structure
- Drainage trenching — French drains, perforated pipe, and gravity-flow drainage systems
- Irrigation trenching — mainline and lateral runs for agricultural and landscape irrigation systems
- Conduit trenching — electrical conduit, data, fiber, or low-voltage wiring routes
- Sewer and septic lateral trenching — gravity-flow lateral runs from structure to sewer main or tank
- Slot trenching — narrow profile (4–8 inches wide) for conduit and small-diameter pipe; faster and less disruptive
- Potholing / spot excavation — hand dig or vacuum excavation to expose existing buried utilities before trenching nearby
- Backfill and compaction — trench backfilled in lifts, compacted to prevent settlement
What Does Trenching Cost in Northern California?
Trenching is priced per linear foot for most standard utility and drainage runs. The rate covers cut and backfill — pipe and conduit installation is typically done by the relevant trade contractor after we cut the trench. Rock, deep cuts, and tight access shift the rate significantly.
- Standard utility trench (12–18 in wide × 24–36 in deep): $5–$15 per linear foot
- Slot trench (4–8 in wide × 18–30 in deep): $3–$8 per linear foot — faster, less material to backfill
- Deep trench (36–60 in): $12–$25 per linear foot depending on width and material
- Rock or hardpan encountered: add $10–$30 per linear foot for ripping or breaking
- Tight access, narrow passage, or interior trenching: add 20–40% for equipment constraints
- Asphalt or concrete cutting required: add $4–$12 per linear foot for saw cut
- Spoils haul-out (if material can't be reused as backfill): priced by volume
- Compaction testing: required by some jurisdictions for utility trench backfill under paved surfaces
USA North 811 — Required Before Every Trench
No trench goes in the ground without a confirmed USA North 811 call. California law requires notification at least 2 business days before digging. Utility locators mark buried lines in the dig area — marks define the tolerance zone. Working within 18–24 inches of a mark requires potholing or hand excavation, not machine cut.
- Submit online at usa811.com or call 811 at least 2 business days before scheduled dig
- All utilities must respond positively before excavation begins
- Marks are valid for 28 days — re-notify for projects that extend beyond the window
- Color code: red = electric, yellow = gas/oil, orange = telecom, blue = potable water, green = sewer/storm
- Private utilities (pool plumbing, irrigation, secondary electrical) are NOT marked by 811 — locate separately
- Within 18–24 inches of any mark: hand dig or vacuum excavation only — no machine cutting
- Hitting a utility without a current 811 notification creates full legal and financial liability
Trench Backfill and Compaction — Why It Matters
A trench that settles after backfill creates surface depressions, cracked pavement, and failed pipe bedding. Proper backfill means placing material in compacted lifts — not dumping and hoping. Under paved surfaces or slabs, compaction testing may be required before paving.
- Backfill placed in 6–8 inch compacted lifts — not dumped all at once
- Pipe zone bedding: typically specified by the engineer or inspector — clean sand or crushed rock around the pipe
- Compaction to 90–95% relative density required under paved surfaces, driveways, and slabs
- Native material reuse: trench spoils reused as backfill where soil type is suitable
- Import base rock or crushed aggregate: used when native spoils are not suitable for structural backfill
- Surface settlement check: trench alignment inspected 30–60 days after completion on high-traffic areas
- Compaction testing by geotech firm: required by some municipalities before paving over trench
Coordinating Trenching With Your Contractors
Trenching is rarely a standalone scope — it's always part of a larger construction sequence. Getting the cut done at the right time (not too early, not after concrete is poured) requires coordination with your plumber, electrician, irrigation contractor, and building inspector. We handle the cut and backfill; your trade contractors handle the pipe and conduit installation.
- Sequence: trench cut first, then trade contractor installs pipe/conduit, then backfill and compaction
- Open trench timing: keep open trench time short — OSHA requires shoring or sloping at 5 feet depth
- Inspector access: some jurisdictions require inspection of pipe bedding before backfill — confirm before covering
- Trench layout: confirm run alignment and depth with the trade contractor before cutting
- Multiple utilities in the same trench: electric and gas in the same trench require specific separation distances per code
- Coordination with concrete contractor: utility stubs must be placed before pad is finished and poured
- Rural sites: septic lateral and leach field trenching requires county health department inspection before backfill
Related Services
Excavation
Dirt removal, trenching, small excavation, rough grading, and site support work.
Drainage Support
Support water flow improvements with grading, trenching, swales, and dirt shaping.
Site Prep
Clearing, demolition, grading, hauling, and equipment work to prep your property.
Grading
Prepare land for pads, driveways, drainage, ADUs, shops, garages, and future construction.
Frequently asked questions
How much does trenching cost in Northern California?
Standard utility or drainage trenching (12–18 inches wide, 24–36 inches deep) runs $5–$15 per linear foot for cut and backfill. Slot trenching for conduit or small pipe runs $3–$8 per linear foot. Rock, hardpan, deep cuts, asphalt saw cutting, and tight access all push the rate higher. Pipe and conduit installation is done by the relevant trade contractor — we provide the trench.
Do I need to call 811 before trenching?
Yes — California law requires a USA North 811 notification at least 2 business days before any excavation. Utility locators mark buried electric, gas, water, sewer, and telecom lines. All utilities must respond positively before work starts. Within 18–24 inches of a mark, hand digging or vacuum excavation is required — no machine cuts. Private utilities like irrigation and pool plumbing are not marked by 811 and must be located separately.
What is the difference between slot trenching and standard trenching?
A slot trench is narrower — typically 4–8 inches wide versus 12–18 inches for a standard utility trench. Slot trenching is faster and produces less spoils, making it more economical for conduit runs, low-voltage wiring, and small-diameter pipe. Standard trenching is used when pipe diameter, bedding requirements, or working access inside the trench requires the wider profile.
How deep does a utility trench need to be in California?
Depth depends on what's being installed. Typical minimums: electric conduit at 24 inches (18 inches under concrete slabs), water lines at 12 inches (24 inches in freeze-risk foothill areas), gas at 12 inches minimum (24 inches preferred), sewer laterals at slope-driven depth (typically 12 inches at the structure, deeper at the main connection). Local utilities and inspectors may require greater depth — confirm requirements before cutting.
Do you backfill and compact after trenching?
Yes — backfill and compaction are included in our trenching scope. Material is placed in 6–8 inch lifts and compacted to specification before the next lift. Under driveways, paved surfaces, or slabs, we compact to 90–95% relative density and can coordinate compaction testing with a geotech firm if required by the inspector. Open trench is closed as quickly as possible after the trade contractor completes their installation.