811 vs. Private Utility Locating: What's the Difference?

Almost everyone who has run a job site knows to "call 811 before you dig." It is the right first step, it is free, and in many cases it is required by law. But a lot of crews learn the hard way that 811 does not mark everything - and the lines it misses are often the ones that stop a job.

Understanding the difference between an 811 public locate and a private utility locate is one of the most important things a contractor or property owner can know before excavation. They are not the same service, they cover different lines, and on a developed commercial site you usually need both.

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What 811 Actually Does

811 is the national "call before you dig" system. When you place a ticket, the request goes out to the public utility owners with infrastructure in your area - the electric, gas, water, and telecom companies - and each one marks the lines it owns near your dig site, usually up to a point of demarcation like a meter.

That coverage is valuable and it is required, but it has a hard boundary: 811 only covers public, owner-operated utilities. It does not investigate the site as a whole, and it does not mark anything past the point where the utility company's ownership ends.

Where 811 Stops - and Private Lines Begin

Past the meter, the lines usually become the property owner's responsibility, and 811 typically will not mark them. On a commercial or industrial site, that can be a large share of what is actually in the ground:

• Site and parking lot lighting circuits
• Irrigation lines and controls
• Private electrical feeds between buildings
• Gas lines running past the meter to detached equipment
• Private water and fire lines
• Data and communication runs across a campus
  

These are exactly the lines a fence auger, a footing, or a trench tends to hit - and treating 811 as if it covered them is a common cause of utility strikes. Relying on 811 alone on private property leaves these lines unmarked and invisible.

What a Private Utility Locate Covers

A private utility locate is a professional investigation of the utilities on your property - including the private lines 811 does not touch. Rather than notifying utility owners to mark their own assets, a private locating company comes to the site and actively investigates what is underground across the whole work area.

Because private lines can be metallic, plastic, documented, or completely unrecorded, this work uses more than one method. Electromagnetic locating traces conductive lines and lines with tracer wire, while GPR investigates non-conductive lines and features EM cannot detect. Together they build a picture of the site that an 811 ticket alone never provides.

Digging on a commercial site? Call 811 for the public lines, then have SiteTwin locate the private utilities 811 won't mark. Send the address and scope for review. Request a locate.

Why You Usually Need Both

This is not an either/or decision. 811 and a private locate cover different lines, and on a developed site the safe approach is to use them together. 811 handles the public infrastructure and satisfies the legal notification requirement. The private locate covers everything past the meter and everything undocumented. Skip either one and you leave a category of utilities unaccounted for.

Think of 811 as the required baseline and the private locate as the part that makes the site actually safe to dig. Neither replaces the other.

Don't Forget to Verify the Crossings

Whether a line was marked by 811 or by a private locate, a surface mark is still an estimate of horizontal position, not a guarantee of depth. For high-consequence crossings - a bore under gas, a deep trench near power - the marks should be confirmed by potholing, which physically exposes the line so the crew works from its real depth and position.

Public and Private Locating Across Texas

Texas commercial and industrial sites are dense with private infrastructure, which is why the private-locate step matters so much here. SiteTwin serves the major metros:

• Houston
• Dallas
• Austin
• Fort Worth
• San Antonio
  

You can also view our service locations.

811 vs. Private Locating FAQ

Does 811 mark private utility lines?

No. 811 notifies public utility owners to mark their own lines, usually up to a meter or point of demarcation. Private lines past that point - lighting, irrigation, private electric and gas - are not covered and require a private locate.

Do I still need to call 811 if I hire a private locator?

Yes. 811 covers the public utilities and is often legally required. A private locate covers the lines 811 does not mark. On a developed site you generally need both.

Is 811 enough for a commercial project?

Usually not. Commercial and industrial sites are full of private utilities that 811 does not mark, so an 811 ticket alone leaves a significant portion of the site unaccounted for.

What's the difference in how they work?

811 notifies utility owners to mark their assets. A private locator physically comes to the site and investigates all utilities in the work area, including undocumented private lines, using EM and GPR.

Cover the Public Lines and the Private Ones

Call 811 for the public utilities, add a private locate for everything past the meter, and verify the high-risk crossings by potholing. That combination is what turns "we called before we dug" into a site that is actually safe to excavate.

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