Utility Potholing in Southern California
Potholing is digging a small test hole to expose a buried utility and confirm where it sits, side to side and in depth. We work across Los Angeles, Orange, Riverside, San Bernardino, San Diego, Ventura, Imperial, Santa Barbara and Kern counties.
We mark the lines before digging, so fewer holes miss.
No blade or bucket touches the utility.
We measure to the top and bottom of each line.
Size, material, spacing and photos of the exposed line.
We design the setup and get the permits the work needs.
Backfilled and restored to the agency’s requirements.
Schedule Potholing
Potholing and Daylighting
Hydro, vacuum and air excavation are methods. Potholing is the whole job of exposing a buried line and confirming where it is, and you will also hear it called daylighting or test holes. The California Underground Safety Board’s 2024 staff report says a pothole has to reveal each facility’s exact horizontal and vertical extents.
The vertical part is what a locate mark can’t give you. Paint on the pavement shows where a line runs but not how deep it is, and records and as-builts are often wrong on depth. Exposing the line gives you the highest level of verified data available on an existing utility.
Hydro or Air Excavation
Lines are exposed with one of two vacuum methods, and which one depends mostly on the soil. Hydro excavation uses pressurized water to loosen the soil and a vacuum to pull it out, which works well in hard or dense ground. Air excavation does the same job with compressed air. It’s the choice where a line shouldn’t get wet, and because the spoil comes out dry, it can often go back in the hole.
With either method, no blade or bucket touches the utility. The surface cut is about 1 ft by 1 ft, and afterward the hole is backfilled and the surface restored to the agency’s requirements.
Potholing Before New Work
A pothole is dug when a design, a bore or a trench depends on where an existing line actually sits. It confirms the line’s position and depth before any equipment gets close to it.
Common reasons to pothole
- Design conflict: A proposed line or structure may cross an existing utility, and the design needs that utility's real position.
- Bore crossings: A directional drill has to cross existing lines, and the bore path has to clear them.
- Trenching near lines: The trench route and depth have to clear the buried utilities beside it.
- Unclear locate marks: The marks on the ground leave questions about what's there or how deep it is.
- Owner requirements: The utility owner requires potholing before anyone works near its line.
- Crowded corridors: Many lines share the same space, and each one needs to be confirmed.
Recorded at Each Hole
What gets recorded at each hole depends on the job, and can include:
- Depth: to the top and the bottom of the utility.
- Type and material: what the line is and what it's made of.
- Diameter: the size of the pipe or conduit.
- Pavement thickness: measured at the cut.
- Number of lines: how many utilities are in the hole.
- Spacing: the distance between lines.
- Color and condition: what the line looks like once it's exposed.
- Photos: of the exposed utility in the hole.
The Potholing Process
Locate and mark first
We start by finding and marking the lines with our utility locating service. Placing each hole on a marked line cuts down on dry holes, the ones that miss the line entirely.
Traffic control and permits
Next comes the traffic control design and setup, along with the permits the work needs.
Expose the utility
Air or hydro vacuum excavation opens a hole about 1 ft by 1 ft.
Record what's in the hole
With the line exposed, it’s time to record the details the job calls for.
Backfill and restore
The hole is then backfilled and the surface restored to the agency’s requirements.
Potholing Questions
What is the difference between potholing and utility locating?
Utility locating finds a buried line from the surface and marks where it runs. Potholing digs down to the line to confirm its position and depth. We offer both, and locating the lines before digging means fewer holes miss the line.
What is daylighting?
Daylighting is another name for potholing. You’ll also hear it called test holes.
Should I use air or hydro excavation?
We choose based on your soil. Hydro works well in hard or dense ground, and air suits lines that shouldn’t get wet, with dry spoil that can often go back in the hole.
How big is a pothole?
The surface cut is about 1 ft by 1 ft.
Do you handle traffic control and permits?
Yes. Traffic control design and setup, along with getting the permits, are part of our potholing service.
How is the surface restored?
The hole is backfilled and the surface restored. How it’s restored depends on the type of surface and what the agency requires.
What areas do you cover?
We offer potholing across Southern California, in Los Angeles, Orange, Riverside, San Bernardino, San Diego, Ventura, Imperial, Santa Barbara and Kern counties.
Our Certifications and accreditations
Why choose Specialized Testing for your Utility Potholing?
We have the experience, Qualification and Expertise to handle your Next Project
