What is Vacuum Potholing?

Every surface geophysics method returns an interpretation. Electromagnetic depth readings drift where lines run close together, and GPR returns a reflection rather than a pipe. Vacuum potholing settles it: compressed air or water breaks the soil, an industrial vacuum lifts it out, and the line is exposed intact so its true depth, material, and outside diameter can be measured and recorded. That measured point is what ASCE 38-22 calls Quality Level A, and it is the only quality level a designer can build to without a tolerance.

What San Francisco Clients Get Out of It

• Turns an interpreted depth into a measured one
• Records pipe material and outside diameter, which no surface method reports
• Non-destructive inside the one-call tolerance zone, where mechanical digging is prohibited
• Small, restorable holes rather than an exploratory trench
• The QL-A input a SUE drawing needs at each design conflict

Vacuum Potholing in San Francisco Conditions

San Francisco sits in a mediterranean climate. Local ground: Clay, Sandy loam, Alluvial. Soil conductivity is the variable that decides how much of a locate radar can contribute, because conductive ground absorbs the radar pulse instead of reflecting it. Primary industries — oil & gas, construction, utilities, municipal, telecommunications — drive steady demand for vacuum potholing across the San Francisco County area.

DigAlert (Southern CA) / USA North 811 (811) requires 2 business days of advance notice before any excavation in California. That notification is free and it is separate from vacuum potholing: it brings out the member facility owners to mark the lines they own, and stops at the meter or the right-of-way. Wait for every member to respond before ground is opened.

When San Francisco Clients Use Vacuum Potholing

• QL-A test holes at design conflicts and utility crossings
• Verifying depth of cover along a directional bore path
• Daylighting lines at bore entry and exit pits
• Exposing utilities at foundation, pier, and pile locations
• Confirming pipe material and outside diameter before a tie-in
• Non-destructive digging inside the one-call tolerance zone
• Uncovering a repair point pinpointed by leak detection

What a Vacuum Potholing Quote in San Francisco Depends On

Locating is quoted per job rather than off a rate card, because the work is a search and a search scales with the site rather than with the clock. On a San Francisco job, the things that move the number are how much ground has to be covered, how many targets are in play, whether there are meters, valves, risers, or panels a transmitter can be clipped to, what the lines are made of, what the local ground (clay, sandy loam, alluvial) does to the instruments, and whether you need surface marks or a record you keep.

Describe the job once through Utility Hotline. Our team reviews the request, then locating companies covering San Francisco and San Francisco County send you their own quotes, so you are comparing them against the same scope. It is free to request.