If you have ever planned a home improvement project that involves digging, you have likely seen white trucks labeled “USIC” or noticed small, colorful flags appearing in your yard. These are the visible signs of a critical safety process known as utility locating. USIC, which stands for United States Infrastructure Corporation, is the largest provider of underground utility locating services in North America.
Understanding what USIC does and how the locating process works is essential for homeowners, DIY enthusiasts, and professional contractors alike. Excavating without knowing what lies beneath the surface can lead to expensive repairs, service outages, and serious physical injury. This article provides a comprehensive look at USIC utility locating and the steps you need to take to ensure your next project is safe and compliant with the law.
What is USIC Utility Locating?
USIC is a private company contracted by utility providers—such as electric, gas, water, and telecommunications companies—to identify and mark the location of underground pipes and cables. They act as the bridge between the utility companies that own the infrastructure and the people who need to dig near it.
It is important to understand that USIC does not own the utility lines themselves. Instead, they are experts in detection technology. When a person notifies the local “Call Before You Dig” center (811), USIC technicians are often the ones dispatched to the site to find and mark the exact path of the utility lines using specialized equipment and paint.
The Importance of the 811 System
The utility locating process almost always begins with a call or online request to 811. This is a free national service created to prevent damage to underground infrastructure. In most states, calling 811 is not just a safety recommendation; it is a legal requirement before any type of excavation begins.
When you contact 811, they notify all member utility companies in your area about your intent to dig. Those companies then send out locators, like those from USIC, to mark their respective lines. You should typically submit your request at least two to three business days before you plan to start working to allow enough time for the technicians to visit your property.
Understanding Utility Flag Color Codes
When a USIC technician visits your property, they will leave behind colored flags or spray-painted lines on the ground. These colors are not random; they follow a standardized code established by the American Public Works Association (APWA). Knowing these colors helps you understand what is buried beneath your feet.
- Red: Electric power lines, cables, conduit, and lighting cables.
- Yellow: Gas, oil, steam, petroleum, or gaseous materials.
- Orange: Communication, alarm or signal lines, cables, or conduit (including fiber optics and CATV).
- Blue: Potable (drinking) water.
- Green: Sewers and drain lines.
- Purple: Reclaimed water, slurry, and irrigation lines.
- Pink: Temporary survey markings.
- White: Proposed excavation limits (used by the person digging to show where they plan to work).
How USIC Locates Underground Lines
Locating underground utilities is a scientific process that requires specialized training. USIC technicians use various methods to find lines that are often several feet underground and invisible from the surface. The most common method is electromagnetic induction.
Technicians use a transmitter to apply an electromagnetic signal to a known point of a utility line, such as a meter or a valve. They then use a receiver to detect that signal as it travels along the buried pipe or wire. By following the strongest signal, the technician can trace the exact path of the utility and mark it on the surface with high accuracy.
In cases where lines are non-conductive, such as plastic water pipes or certain types of fiber optics, technicians may use tracer wires that were buried alongside the pipe or ground-penetrating radar (GPR). These tools allow USIC to provide a clear map of the “unseen” world beneath your yard.
The Safe Digging “Tolerance Zone”
Once USIC has marked the utilities, your job is to dig carefully. The markings provided by locators indicate the approximate location of the utility. Because there can be a small margin of error, most states recognize a “tolerance zone” around the marked lines.
The tolerance zone is typically 18 to 24 inches on either side of the outer edge of the utility line. If you are digging within this zone, you should avoid using heavy machinery or power tools. Instead, use hand tools like shovels and proceed with extreme caution. This ensures that you do not accidentally nick or pierce a line that may be slightly offset from the paint mark.
Common Questions About USIC and Locating
Can I move the flags once they are placed?
No, you should never move or remove utility flags until your project is completely finished. These flags are legal markers. If you accidentally move them, you lose the reference point for where it is safe to dig. If flags are disturbed by wind or lawn mowing, you should contact 811 for a “remark” request.
Does USIC mark private lines?
Generally, USIC and 811 locators only mark public utilities that run from the main street to the meter. They typically do not mark private lines, such as a gas line running to a backyard grill, electric lines to a detached garage, or lawn sprinkler systems. For these, you may need to hire a private locating service.
What should I do if I hit a line?
If you accidentally strike a utility line, even if it seems minor, stop digging immediately. If you smell gas or hear a hissing sound, evacuate the area and call 911. For other utilities, contact the utility company directly so they can inspect the line for damage that could cause future failures.
Why Professional Locating Matters
The services provided by USIC are essential for maintaining the integrity of our modern infrastructure. Every year, thousands of utility strikes occur across the country, leading to power outages, internet interruptions, and dangerous gas leaks. Most of these incidents are entirely preventable by following the 811 process and respecting the marks left by USIC technicians.
By taking the time to understand the locating process, you protect yourself from potential liability and keep your neighborhood safe. Whether you are planting a tree, installing a fence, or building a deck, the few days you wait for a USIC technician to mark your property are well worth the peace of mind they provide.
For more information on home safety and property management, explore our other helpful guides on maintaining your home and yard. Staying informed is the best way to handle any project with confidence and ease.