Locates and prevention basics5 sections
The two regional services — and why using the wrong one matters
California utility locating is split regionally: DigAlert covers Southern California (Los Angeles, Orange County, San Diego, Inland Empire, Bakersfield/Kern, Santa Barbara and surrounding counties); USA North 811 covers Northern and Central California — and also the state of Nevada, a detail worth knowing if you work projects across the state line.
Filing with the wrong regional service, or assuming one covers the whole state, is a real and avoidable way to end up without a valid, documented locate request for a project.
Sources for this section
- DigAlert — Southern California Utility LocateVerified 2026-08-26
- USA North 811 — Northern/Central California Utility LocateVerified 2026-08-26
How the locate request process actually works
A locate request must be filed before excavation begins, with a required waiting period (California law generally requires at least two business days) before digging can start, giving utility owners time to mark their lines. Marks use a standard color code — the same colors nationally — indicating what type of utility is present at each mark.
The request itself is free. The cost of skipping it, or digging before the waiting period elapses, is what this entire guide exists to help a contractor avoid.
What the documentation is for, and what it can show
Filing the request is necessary but not sufficient — keeping the confirmation number, the marked utility locations (photographed before work begins), and records of the actual waiting period observed is what supports a contractor's position if a strike happens anyway despite an accurate-seeming mark.
This documentation matters most exactly when it seems least necessary — on a routine job where nothing unusual is expected, which is precisely when documentation habits tend to slip.
What can happen after a utility strike
A strike triggers immediate safety obligations (evacuating the area for a gas or electrical strike, contacting the utility owner and emergency services as appropriate) separate from the insurance and liability questions that follow. General liability typically responds to third-party property damage and any resulting business interruption to the utility, but the size of a utility strike loss can exceed what a smaller excavation contract's typical coverage anticipates.
Whether a strike was despite an accurate mark (utility owner's inaccurate marking) or because a locate wasn't properly filed changes the liability picture significantly — which is exactly why the documentation habits above matter as much before a strike as during the claim after one.
A real root cause analysis after a strike — not just a summary that a line was hit — should identify whether the locate request was accurate, whether potholing actually confirmed depth before mechanized excavation, and whether the crew followed the documented process. This is what both prevents a repeat incident and gives you a real, credible account if the strike leads to a claim or dispute over fault.
Building strike prevention into standard jobsite practice
The contractors with the fewest strikes treat the locate request as a standard, non-negotiable step built into every excavation project's timeline — not a box checked only when a client or inspector asks about it. Training crews to recognize and respect the color-coded marks, and to stop and re-verify if a mark looks inconsistent with expected utility routing, catches problems before they become claims.
Gleason Insurance Brokers works with excavation, grading, and utility-adjacent contractors throughout California on coordinating this exposure with the right liability and pollution coverage — call 844-978-7283 or request a quote to review your current program against this specific risk.
When something goes wrong4 sections
Utility strike risk specific to paving and grading crews
Paving and grading contractors sit closer to utility strike risk than most other trades simply because of what the work involves — cutting, compacting and grading soil where underground utilities are often shallower and less predictably located than site plans suggest. A strike involving a piece of towed or transported equipment adds a commercial auto and inland marine dimension on top of the general liability question, which is why this exposure often spans more than one policy at once.
Calling for a locate before digging is the operational control; having coverage structured to actually respond if a locate was missed, wrong, or the strike happened anyway is the insurance side of the same problem — both matter, and neither substitutes for the other.
Joint trench coordination and utility relocations
Joint trench work — coordinating electric, gas, water, sewer and telecom in a shared excavation — multiplies the utility coordination problem instead of simplifying it: each utility has its own clearance requirements, its own inspection sequence, and its own sign-off before backfill, and a joint trench that satisfies one utility's requirements can still fail another's if the coordination wasn't planned across all of them from the start. Utility relocations add a further layer — moving an existing line out of the way of new construction requires coordination with the utility that owns it, on their timeline, which frequently doesn't match the contractor's own schedule.
Both of these are common points where a project's schedule assumptions and the utility's actual process diverge, and that divergence is exactly what turns into cost overruns and disputes when it isn't planned for. Building realistic lead time for utility relocations into the schedule from the start — not treating a relocation request as something that happens quickly once submitted — is one of the more effective ways to keep a project moving instead of stalling out waiting on a utility company's own internal timeline.
Sources for this section
- PG&E — Pacific Gas and ElectricVerified 2026-08-26
Utility strike liability: who actually pays, and for what
When an underground utility strike happens, the cost exposure runs wider than the repair bill the utility company sends: service interruption claims from affected customers, environmental cleanup if the strike involves a gas or pollution exposure, and in serious cases bodily injury or property damage claims from the surrounding area can all follow from a single strike. Which party bears which cost depends heavily on the documentation in place at the time — whether a proper DigAlert/811 locate request was made and documented, whether potholing confirmed the utility's actual depth and location before excavating, and whether the excavation method and depth matched what the locate documentation indicated.
A contractor with complete locate documentation and a demonstrated standard practice of confirming existing conditions before excavating is in a fundamentally different position, both for insurance claim handling and for any dispute over responsibility, than one without that record — even when the strike itself happens despite doing everything right, since utility mismarking and unmapped facilities do occur. The documentation is what allows a claim to be handled as a covered loss rather than becoming a liability dispute about who failed to take reasonable precautions.
Emergency response when a strike happens mid-excavation
The first few minutes after a suspected utility strike matter more than almost any other moment in the sequence, and having a clear, practiced response — not an improvised one — is what limits both the physical damage and the liability exposure that follows. For a gas line strike, the standard response is to stop work, evacuate the immediate area, avoid anything that could create a spark, and call 911 and the utility's emergency line immediately — not to attempt to inspect or fix the strike itself. For an electrical strike, de-energizing before anyone approaches, and treating any contact as live until the utility confirms otherwise, is the safe default.
Documentation starts immediately after the immediate safety response, not after the fact: photos of the strike location, the locate markings that were in place, the excavation method being used, and the depth reached all become critical to both the insurance claim and any question of responsibility that follows. Having this response sequence written down and reviewed with the crew before it's ever needed — not improvised in the moment — is what keeps a bad situation from becoming a worse one.
Coordinating with each utility4 sections
Electric utility coordination: PG&E, SMUD, TID, MID and municipal utilities
Which electric utility you're coordinating with in California depends entirely on the project's location, and the process differs meaningfully between an investor-owned utility like PG&E and a municipal or irrigation-district utility like SMUD, TID or MID. Each has its own design standards, application process and construction requirements — assuming one utility's process applies because a nearby project used it is a real, avoidable source of schedule delay.
Design, service and transformer requirements generally follow a similar sequence regardless of utility: submit a service application with load requirements, receive a design (often requiring a specific transformer pad location and clearances the site plan has to accommodate), and schedule construction and inspection before the service is energized. Meter requirements — location, access clearance, and sometimes a specific meter type for the load class — are set by the utility, not negotiable at the contractor's convenience.
Energization delays are one of the more underestimated schedule risks on a project. Under CPUC-adopted timelines, PG&E's own average target for a distribution extension is around 182 calendar days, with a maximum of up to 357 days — and the equipment itself can be the actual bottleneck: transformer procurement lead times of 16 to 52 weeks are real and reported industry-wide, not a worst-case outlier. Submitting the electric service application early, and confirming transformer lead time directly rather than assuming standard stock availability, is a real, practical way to keep a project's energization date from becoming its critical path.
Sources for this section
- SMUD — Sacramento Municipal Utility DistrictVerified 2026-08-26
- TID — Turlock Irrigation DistrictVerified 2026-08-26
- MID — Modesto Irrigation DistrictVerified 2026-08-26
Natural gas coordination: design, relocations and inspection requirements
Gas service coordination runs on a similar design-then-construction sequence as electric, but carries its own inspection and safety requirements throughout — a gas line application generally needs the same early submission discipline as an electric one, since gas main extensions and service installations go through their own utility design review before construction can start.
Gas relocations and shutdowns require direct coordination with the utility on their schedule, not the project's — a planned shutdown for a tie-in or relocation typically needs advance notice and utility crew availability, and an emergency shutdown (from a strike or suspected leak) triggers an entirely different, safety-first sequence rather than a scheduled one.
Pressure testing and inspection are non-negotiable steps before a new or relocated gas line is put into service — the utility or its inspector generally verifies the installation meets code and pressure requirements before allowing gas to flow, and skipping ahead of that inspection sequence is both a safety violation and a real cause of rework if the line fails testing after backfill.
Water district coordination: domestic service, fire service, backflow and acceptance
Domestic water service and fire service are generally two separate connections with their own design and sizing requirements, even on the same project — a fire service line is sized for fire flow, not domestic demand, and treating the two as interchangeable during design is a common source of a failed plan check or a costly redesign.
Backflow prevention is a real, statewide compliance requirement, not a discretionary add-on: California's Title 17 (Article 2, §7605(c)) generally requires backflow prevention assemblies to be tested at least annually by a certified tester, with results submitted to the local water provider — local water districts each administer this with their own forms, fees and approved-tester lists, so confirm the specific requirement with the water district serving the project.
Acceptance documentation — pressure test results, as-built drawings, and the water district's own sign-off — is what actually closes out a water system installation. A system that passes pressure testing but never receives formal agency acceptance isn't finished from the district's perspective, regardless of how the work actually performs.
Sewer agency coordination: gravity sewer, force mains, laterals and acceptance
Gravity sewer mains, force mains and individual laterals each have their own design and inspection requirements, and a sewer agency generally reviews all three differently — a force main (which moves wastewater under pressure rather than by gravity) carries its own pressure-testing and material requirements distinct from a standard gravity line.
CCTV inspection is the standard method sewer agencies use to verify a new or relocated line before accepting it — commonly following NASSCO-standard video inspection practices, checking pipe condition, joints and lateral connections along the full run. Requirements vary by agency (some require the agency's own inspector present during the CCTV run, some review submitted footage after the fact), so confirm the specific process with the sewer agency serving the project rather than assuming one jurisdiction's practice applies everywhere.
Acceptance and maintenance periods follow CCTV and pressure testing, not before — many agencies also impose a maintenance or warranty period after acceptance, during which the contractor remains responsible for defects that surface after the line is in service. Confirm both the acceptance testing requirements and the length of any post-acceptance maintenance obligation before finalizing a project schedule and closeout budget.
Verification, acceptance and the usual stalls3 sections
Potholing: positive identification before mechanized excavation
Potholing is the practice of exposing an underground utility by hand or vacuum excavation to positively confirm its exact depth and location before mechanized digging begins nearby — a locate mark tells you a utility is approximately there; potholing is what actually confirms it, which is why the two aren't interchangeable steps.
Vacuum excavation — using pressurized air or water plus a vacuum system to remove soil without the cutting action of a backhoe or trencher — is the standard method for potholing near a confirmed utility, precisely because it exposes the line without the same risk of striking it that mechanized excavation carries.
Existing condition verification through potholing matters most on a project where site plans and record drawings might not reflect what's actually in the ground — utilities get added, moved or abandoned over time in ways records don't always capture. A contractor with a documented practice of potholing before mechanized excavation near a confirmed utility is in a materially different position, both operationally and for a later claim, than one who excavated straight to the locate mark without confirming it.
Utility acceptance: testing, record drawings and turnover
Utility acceptance is the formal process that closes out a utility installation with the owning agency — and it's a distinct, later step from simply passing a pressure test or CCTV inspection. The turnover package generally needs to include test results, as-built (record) drawings showing what was actually built, and any other documentation the specific agency requires before it will formally accept the utility as complete.
Agency signoff is what actually transfers responsibility for the utility from the contractor to the owning agency — without it, a completed-looking installation can remain the contractor's responsibility indefinitely, which matters directly for both project closeout and ongoing liability exposure.
Maintenance and warranty obligations frequently continue past acceptance, not before it — many agencies require a defined maintenance period after signoff during which the contractor remains on the hook for defects that surface in service. Confirm the specific turnover requirements and any post-acceptance maintenance period with each agency early, since assembling record drawings and test documentation after the fact is far more difficult than building the file as the work happens.
Utility project killers: the mistakes that actually stall a project
Late applications are one of the most common, most avoidable causes of a utility-driven delay — electric, gas, water and sewer coordination all run on the utility's or agency's own processing time, and submitting an application late doesn't just delay that step, it pushes every downstream step that depends on it.
Unresolved conflicts — a new utility routing that clashes with an existing one, or a design that doesn't account for another utility already in the ground — and incomplete easements are both the kind of problem that's cheap to catch early and expensive to discover mid-construction, when redesign and re-approval eat directly into the schedule.
Failed tests and missing record drawings are the two ways a project can look finished and still not be accepted: a pressure or CCTV test that fails means rework before resubmission, and a turnover package missing the as-built drawings an agency requires can hold up formal acceptance even when the actual installed work is sound. Each of these five failure modes shares the same underlying cause — treating utility coordination as a background task instead of a tracked, scheduled part of the project — which is exactly why a dedicated utility coordination log and contact tracker pays for itself on any project with real utility scope.
How to File a Utility Locate Request Before Excavating in California
The required steps to request a utility locate before excavation, so work doesn't start before lines are marked.
Determine the correct regional service
Use DigAlert for Southern California counties or USA North 811 for Northern/Central California and Nevada — filing with the wrong service isn't valid for that project.
File the request before excavation begins
Submit the locate request before any digging starts. California generally requires at least two business days' notice, and the request itself is free.
Wait the required period and review the marks
Standard color-coded marks indicate the type of utility at each location — confirm the marks are present and consistent with expected utility routing before digging.
Document the confirmation and photograph the marks
Keep the confirmation number and photograph marked locations before work begins — this supports your position if a strike happens despite an accurate-seeming mark.
Frequently asked questions
14 questions — start typing to filter
Which utility locate service do I use in California?
DigAlert for Southern California (LA, Orange County, San Diego, Inland Empire, Bakersfield/Kern, Santa Barbara and surrounding counties); USA North 811 for Northern and Central California, which also covers Nevada.
How long do I have to wait after filing a locate request before digging?
California generally requires at least two business days after filing before excavation can begin — confirm the current exact requirement with the regional service when filing.
Is there a cost to file a utility locate request?
No, the request itself is free. It's one of the only completely free risk-prevention steps available to an excavation contractor.
What should I document beyond just filing the request?
The confirmation number, photographs of the marked utility locations before work begins, and a record of the waiting period actually observed — this is what supports your position if a strike happens despite an accurate mark.
What happens if a utility is struck despite an accurate locate request?
Safety obligations come first (evacuation, contacting the utility and emergency services as needed), followed by a liability review that considers whether the mark itself was accurate — which is why your own documentation matters.
Does general liability cover a utility strike?
Typically yes for property damage and resulting business interruption, but strike losses can exceed what a smaller excavation contract's typical coverage anticipates — worth reviewing this exposure explicitly.
Does USA North 811 really cover Nevada, not just Northern California?
Yes — USA North 811's actual service territory covers Nevada as well as Northern and Central California, which matters for contractors working projects across the state line.
What do the different mark colors mean?
Utility locate marks use a standard national color code indicating the type of utility present at each location (e.g., different colors for gas, electric, water, communications) — crews should be trained to recognize and respect them.
What's the single biggest cause of preventable utility strikes?
Skipping the locate request entirely, or digging before the required waiting period elapses — both are avoidable with a standard, non-negotiable jobsite process.
Can Gleason Insurance Brokers help review my coverage for this specific exposure?
Yes — we work with excavation, grading and utility-adjacent contractors throughout California to coordinate liability and pollution coverage against this exact risk.
How long is a DigAlert or USA North 811 locate ticket valid before it needs renewal?
Locate tickets are generally valid only for a limited window — commonly cited around 28 calendar days — and need to be renewed if excavation continues past that period. Confirm the current validity window and renewal process directly with the regional service (DigAlert or USA North 811) covering your project, since letting a ticket lapse mid-project is a real, avoidable way to end up excavating without a valid locate on file.
What's the difference between a utility locate and potholing?
A locate mark (from DigAlert/USA North 811) tells you a utility is approximately in a given location; potholing — typically by vacuum excavation — physically exposes the utility to confirm its exact depth and position before mechanized excavation nearby. They're sequential steps, not substitutes for each other.
How often does California require backflow prevention devices to be tested?
Generally at least once a year, under California Title 17 (Article 2, §7605(c)), by a certified backflow tester, with results submitted to the local water provider. Local water districts each administer their own forms, fees and approved-tester lists on top of the state requirement — confirm specifics with the district serving your project.
Why do electric utility energization timelines matter for project scheduling?
Under CPUC-adopted timelines, PG&E's own average target for a distribution extension is around 182 calendar days, with a maximum of up to 357 days — and transformer procurement alone can take 16 to 52 weeks. Submitting the electric service application early and confirming transformer lead time directly, rather than assuming standard availability, is a real way to keep energization from becoming a project's critical path.