811 Dig: Safe Excavation Starts Here

Let’s clear up the most dangerous myth in excavation: calling 811 does not get every buried line on your property marked. While it’s a legally required and essential first step, the 811 service only locates public utilities—the lines owned by utility companies running up to the meter. Everything else, from power lines feeding a detached building to irrigation systems and fire mains, is considered private and will remain invisible. Assuming the 811 marks represent a complete picture is a mistake that leads directly to costly strikes. This guide breaks down exactly what to expect from the 811 dig process, how to interpret the markings you see, and why supplementing it with private locating is the only way to ensure a truly safe site.

Key Takeaways

Know the Difference Between Public and Private Utilities: Calling 811 is legally required to locate public utilities like main gas and water lines. However, the service stops at the meter, leaving you blind to private lines like power to outbuildings or site-specific fire mains, which are your responsibility to find.
Master On-Site Digging Rules: The colored paint and flags are just an approximation. Always respect the tolerance zone—typically 18-24 inches on each side of a mark—by hand digging or using soft excavation methods to visually confirm a utility's exact location before using heavy equipment.
Invest in a Complete Subsurface Map: For full site awareness and risk management, you need to see beyond the 811 marks. Professional private locating uses advanced tools like GPR to find unmapped, non-metallic, or deep utilities, giving you a reliable map to prevent costly strikes and keep your project on schedule.

What is 811? (And Why You Must Call Before You Dig)

Before any dirt moves on your project, one phone call is non-negotiable: dialing 811. Think of it as the first step in any successful excavation, a free and essential service that connects you with local public utility companies. Making this call (or submitting a ticket online) notifies these companies that you plan to dig, giving them a chance to come out and mark the approximate location of their underground lines with paint or flags.

This simple action is your first line of defense against hitting a buried gas line, water main, or fiber optic cable. A utility strike isn't just a costly mistake that causes outages and project delays; it's a serious safety hazard that can lead to injury or worse. The entire 811 system is designed to prevent these dangerous and expensive accidents. While it’s a critical starting point, it’s important to remember that 811 only covers public utilities. We’ll get into what that means for your project a little later.

The purpose of the 811 service

The main goal of the 811 service is to act as a communication hub for damage prevention. Instead of you having to track down every individual utility company that might have assets on your property, 811 does the legwork for you. When you submit a request, the 811 center notifies its member utility companies about your planned excavation. Each of these public utilities then sends a locator to your site to mark their lines. This process ensures everyone from homeowners planning to plant a tree to general contractors breaking ground on a new facility follows a standardized safety procedure to protect our vital underground infrastructure.

Legal requirements for excavation

Here’s the bottom line: in every state, the law requires you to contact 811 before you dig. This isn't just a friendly suggestion or a best practice—it's a legal mandate. Failing to call can result in significant fines, liability for repair costs if you damage a line, and potential legal action. While specific regulations, like how much advance notice you need to give, can vary by state, the core requirement is universal. This legal framework is in place to protect you, your crew, and the public from the consequences of a utility strike. Always check your local 811 center's rules to ensure you are fully compliant.

Who needs to make the call

A common point of confusion is who actually needs to pick up the phone. The responsibility lies with the person or company performing the excavation. If you’re a property owner and you’ve hired a contractor to do the digging, that contractor is legally obligated to contact 811. If you are handling the excavation yourself, the responsibility is yours. As a general contractor or project manager, it’s your job to ensure this call is made for every project, no matter how small. Never assume the call has been made; always verify that a ticket has been created and is active before breaking ground.

Common myths about 811

One of the most dangerous myths about 811 is that it marks every single buried line on a property. This is not true. The 811 service only locates and marks public utilities—the lines owned and maintained by utility companies. They will not mark private utilities, which include anything installed past the service meter. Examples include power lines running to a detached garage, septic systems, irrigation lines, or propane gas lines. Assuming the 811 marks represent everything underground is a mistake that can lead directly to a utility strike. This gap in coverage is why private utility locating is a necessary next step for comprehensive site safety.

How the 811 Call Process Works

Calling 811 is the first, non-negotiable step for any excavation project. It’s a free, federally mandated service that connects you with local public utility companies to get their underground lines marked. While it’s a critical starting point for safety, understanding the process—from the initial call to waiting for the paint to hit the ground—is key to keeping your project on schedule. Think of it as the essential first layer of due diligence before you break ground. The process is straightforward, but it requires planning and patience to avoid unnecessary delays or costly mistakes.

Information you'll need to provide

When you call 811 or submit a request online, you’re creating what’s known as a “one-call ticket.” An operator will ask for specific details about your project to ensure the right utility companies are notified. Be prepared to share the exact address or location of the dig site, including cross streets. You’ll also need to describe the type of work you’re doing, like trenching for a new fiber line or drilling for soil borings, and the planned start date and time. Providing accurate information is the best way to get a clear response.

How to plan your project timeline

Patience is a virtue, especially when it comes to excavation. You should always call 811 several days before you plan to start digging. The exact waiting period varies by state, but a good rule of thumb is to allow at least two to three full business days—not including weekends or holidays—for a response. This buffer gives public utility companies enough time to receive your ticket, schedule a locator, and visit your site. Rushing this step can lead to unmarked lines and dangerous situations, so build this waiting period directly into your project schedule.

What happens after you notify 811

Once your ticket is submitted, the one-call center sends it to its member utility companies with assets in your project area, including providers of electricity, gas, water, and telecom. Each company is then responsible for sending a locator to mark the approximate location of their buried lines. It’s important to remember that this service only covers public utilities—the lines running up to the meter or service connection point. Any private lines beyond that point, like power to a detached garage or an irrigation system, will not be marked.

Understanding response times

After the mandatory waiting period, you should see colored flags or paint on the ground. Before you dig, you must confirm that all affected utility companies have responded. You can usually check the status of your ticket online through your state’s 811 portal, which shows the status for each notified utility. A company will either mark its lines with a specific color or issue an "all clear" if they have no infrastructure in the area. Never assume that a lack of marks means the area is clear—always verify the response status for every single utility on your ticket.

How to Read Utility Line Markings

After you call 811, you’ll see flags and spray paint appear on your job site. This isn’t random graffiti—it’s a critical map of the buried infrastructure beneath your feet. Understanding these markings is the first step toward a safe and successful excavation. Think of it as a universal language that tells you what’s below and where you need to be extra careful.

Each color and symbol provides a clue about the type and location of a utility line. While the 811 service is essential for identifying public utilities, remember that these marks are just the starting point. They indicate the approximate location of lines owned by utility companies, but they won’t show you the private lines that run from the meter to a building or other facilities on your property. Learning to read these public markings correctly will help you protect your crew, prevent costly damages, and know exactly when you need to bring in a private locator for a complete picture.

What each color means

The colors used in utility markings follow a standardized system to prevent confusion. Each color corresponds to a specific type of underground line, so you can immediately identify what you’re dealing with. Committing these to memory is one of the smartest things you can do for job site safety.

Here’s a quick guide to the APWA uniform color code you’ll see on site:

Red: Electric power lines, cables, or conduit
Yellow: Gas, oil, steam, petroleum, or gaseous materials
Orange: Communication lines, alarms, or signal lines (like fiber optics, phone, or TV)
Blue: Potable (drinking) water
Green: Sewers and drain lines
Purple: Reclaimed water, irrigation, and slurry lines
Pink: Temporary survey markings
White: Proposed excavation area
How to interpret the marks on the ground

The paint and flags left by public utility locators trace the approximate path of a buried line. A solid line of paint indicates the estimated center of the utility, while flags are often used in grassy or unpaved areas to increase visibility. These marks are your guide for where the utility is supposed to be, based on the utility owner’s records.

This service is provided for free when you call 811 before you dig. It’s a legal requirement and a crucial safety measure. However, it’s important to treat these marks as a guide, not an exact science. The actual depth and location can vary, and the marks don’t provide information on abandoned lines or private infrastructure. They simply tell you that a public utility is believed to be in the immediate vicinity.

Understanding tolerance zones

Once the lines are marked, you need to respect the tolerance zone. This is a designated safety buffer that extends a specific distance from the outer edges of a marked utility line—typically 18 to 24 inches on each side, though you should always confirm your local state requirements. Within this zone, you cannot use mechanized digging equipment like a backhoe or trencher.

The only way to excavate within the tolerance zone is carefully, by hand or with soft digging techniques like vacuum excavation. This practice, often called "potholing," is designed to visually confirm the exact location and depth of the utility without damaging it. Ignoring the tolerance zone is one of the fastest ways to cause a dangerous utility strike, leading to project delays, expensive repairs, and serious safety risks.

How long the markings are valid

Utility markings aren’t permanent. The paint can fade from sun exposure, wash away in the rain, or get covered by dirt and debris. Because of this, markings are only valid for a specific period, which varies by state but is often between 10 and 30 days. Before you break ground, it’s your responsibility to confirm that the markings are still fresh and visible.

If your project is delayed for any reason, you’ll need to submit a new 811 ticket to have the lines re-marked. It’s also critical to wait until all utility companies have responded to your initial request before you start digging. A positive response confirmation from each utility ensures you have the most current information. Starting work prematurely could mean you’re digging blind around an unmarked—and potentially hazardous—utility line.

Essential Safe Digging Practices

Once the flags and paint are on the ground, the real work begins. But safe excavation is more than just avoiding the marks. It’s about having a clear, repeatable process that protects your crew, your equipment, and the public infrastructure buried just beneath the surface. Following a consistent set of practices minimizes risk and keeps your project moving forward without costly delays or dangerous accidents. From your initial site walk to how you respond in an emergency, every step matters. Here’s how to approach digging with the diligence it requires.

Your pre-digging checklist

Before any bucket hits the dirt, run through a final safety check. First and foremost, always call 811 a few business days before your planned start date. Have your project details ready, including the address and the specific area you’ll be excavating. Once your ticket is submitted, confirm that all utility operators have responded. If the start time arrives and a utility hasn’t marked its lines or confirmed they are clear, do not dig. Instead, contact 811 again to report the non-response. Finally, walk the site to ensure the physical marks on the ground match the information on your ticket.

When to hand dig

The painted lines and flags on the ground are not an exact science; they are an approximation. The area immediately surrounding a marked utility line is known as the tolerance zone, which is typically 18 to 24 inches on either side of the mark. Within this zone, mechanical equipment is off-limits. You must dig carefully by hand with a shovel or use soft-digging methods like vacuum excavation to expose the utility and verify its exact depth and location. This process, often called potholing or daylighting, is the only way to be certain you won’t cause a strike. It’s a non-negotiable step for any excavation near marked lines.

Choosing the right equipment

Using the right tool for the job is critical for safety. While excavators and backhoes are great for bulk earthmoving, they are the wrong choice for digging near known utilities. For work inside the tolerance zone, your primary tools should be shovels. For larger projects or when dealing with tough soil conditions, hydro or vacuum excavation is the safest and most efficient method. This equipment uses pressurized water or air to break up soil, which is then removed with a high-powered vacuum. It’s a precise, non-destructive way to safely expose buried pipes and cables without risking damage.

What to do in an emergency

Even with careful planning, accidents can happen. If you strike a utility line, your crew’s response needs to be immediate and decisive. First, stop all work. If you hit a line but there is no visible leak or immediate danger (like a fiber optic cable), clear the area and call the utility company directly. You should also notify 811 about the incident. If you strike a gas line or cause a water main break, evacuate the area immediately. Get a safe distance away, and then call 911 and the utility provider. Do not attempt to stop a leak or repair the damage yourself.

Beyond 811: Why You Need Private Utility Locating

Calling 811 is the essential first step for any excavation project, but it’s just that—a first step. The public utility locating service is designed to mark the lines owned by its member companies, like the main gas, water, and electric lines running up to your property. However, their service literally stops at the meter. Any utility lines running from the meter to a building, or between buildings on a property, are considered private. This creates a huge information gap that can lead to dangerous and expensive utility strikes.

This is where private utility locating comes in. Professional locators use advanced methods like Ground Penetrating Radar (GPR) and electromagnetic (EM) locating to find what 811 misses. Think of it as completing the picture. While 811 gives you the broad strokes, a private locator fills in all the critical details, including non-metallic pipes, abandoned lines, and utilities that were never properly mapped. For general contractors, facility managers, and environmental consultants, relying only on 811 markings is a significant risk. A comprehensive subsurface utility map from a private firm is your best defense against project delays, budget overruns, and serious safety incidents.

The limits of public utility marking

The 811 system is a valuable, legally required resource, but it’s important to understand its boundaries. The service coordinates with public utility companies to mark the lines they own and maintain. However, they won’t mark anything that isn't owned by one of their members. This means utilities installed by private contractors—for irrigation, outdoor lighting, or fire mains—will be completely missed. Furthermore, the response time for 811 can vary, sometimes causing delays before your project can even begin. Relying solely on public markings leaves your team exposed to the risk of hitting an unknown line, which can cause service outages, costly repairs, and worker injuries.

What to know about private utilities

So, what exactly is a private utility? A simple rule of thumb is that any utility line past the meter or main shutoff valve is considered private. The property owner is responsible for locating and protecting these lines, not the public utility company. Common examples on commercial or industrial sites include power lines running to parking lot lights or secondary buildings, water lines for fire hydrants and sprinkler systems, and fiber optic cables connecting different facilities on a campus. On a residential property, this could be a gas line to a pool heater or a power line to a detached garage. Without a private utility locating service, these assets remain invisible and vulnerable during any excavation.

How to find deep or unmapped lines

Many properties, especially older industrial sites or large campuses, have a complex and often undocumented history of underground infrastructure. Over the years, lines may have been installed, abandoned, or rerouted without any updates to site plans. These "ghost" utilities, along with deeply buried lines, pose a serious challenge. Standard locating methods may not detect them, and they certainly won't be marked by an 811 call. This is where advanced techniques become critical. Private locators use tools like GPR that can identify both metallic and non-metallic objects, like PVC or concrete pipes, and can often detect targets at greater depths, giving you a complete and accurate map of the subsurface.

When to call a professional locator

You should call a professional locator before breaking ground on any project where underground utilities could be present. If you’re planning soil borings, trenching for new fiber, upgrading a storm drain system, or simply excavating near existing structures, a private scan is a crucial part of your due diligence. It’s also a smart move if the 811 markings don’t seem to match what you see on the surface, like valves or junction boxes in unmarked areas. While you should always call 911 for an emergency like a suspected gas leak, calling a private locator is a proactive step that demonstrates a commitment to safe digging practices and protects your project, your crew, and your budget.

How to Plan Your Excavation Project

A successful excavation is all in the planning. Before the first shovel hits the dirt, a few key steps can save you from costly delays, dangerous utility strikes, and major headaches. Think of it as your project's blueprint for safety and efficiency. By mapping out your timeline, prepping your site, and running through a final safety check, you set your team up for a smooth, incident-free dig. Let's walk through how to get it right.

Develop a realistic project timeline

Your project schedule can make or break your excavation. The most important thing to remember is that you can't start digging the same day you call 811. You should always call 811 several days before you plan to break ground. This isn't just a suggestion—it's often a legal requirement. This buffer gives public utility companies the time they need to receive the request, dispatch their crews, and mark their lines on your property. Factoring this waiting period into your schedule from the very beginning prevents frustrating delays and keeps your project on track. Don't let a simple phone call become a last-minute emergency.

Prepare your site for digging

Before locators can do their job, your site needs to be ready. Start by pre-marking your proposed excavation area with white paint or flags. This clearly shows the utility crews exactly where you intend to dig, eliminating guesswork. When you contact 811, you'll need to describe this location precisely. Once the request is processed, the public utility companies will send technicians to mark the approximate location of their buried lines. This service is free and is the essential first step in damage prevention. A clearly marked site ensures the locators can work efficiently and accurately, giving you a better starting point for your project.

How weather can affect your project

Don't let Mother Nature derail your project. Weather can have a huge impact on both safety and efficiency. Heavy rain can wash away paint and flags, making utility markings disappear overnight. Snow can cover them completely, forcing you to request a re-mark and causing delays. Digging in frozen or overly saturated ground also increases the risk of a utility strike, as the equipment may be harder to control. Remember, hitting a line can cause service outages for an entire neighborhood, lead to expensive fines and repair costs, and create serious safety hazards. Always check the forecast and adjust your schedule accordingly to keep your crew safe.

Final safety verification steps

The markings are down, but you're not quite ready to dig. Before any equipment starts running, take a moment for a final safety check. First, confirm you've received a positive response from all the utility companies listed on your 811 ticket. Cross-reference the paint and flags on the ground with their responses to ensure nothing was missed. If you see evidence of a utility but no markings, stop and call 811 again. If you do accidentally hit a line, stop digging immediately. Evacuate the area if there's any potential danger, and then call 911 if needed. After that, report the damage to both 811 and the affected utility company. This final check is your last line of defense against a costly accident.

How to Manage Complex Projects

When your project involves more than a simple trench, managing the moving parts can feel like a full-time job. Large-scale commercial sites, dense urban environments, and multi-phase developments require a level of planning that goes far beyond a single 811 ticket. The key is to treat subsurface investigation not as a preliminary checkbox, but as a central part of your project management strategy. From coordinating with a dozen different utility owners to ensuring the marks on the ground are actually accurate, every step demands careful oversight.

A complex project means you’re dealing with more variables, higher stakes, and less room for error. This is where you need to layer your safety protocols and verification steps. Relying on the basic 811 process alone can leave you exposed to significant risks, from costly utility strikes to project-derailing delays. By building a robust plan for utility coordination, site management, and quality control, you can stay in control of the job site from start to finish.

Coordinating with multiple utilities

On a large project, you’re not just dealing with one or two utility companies—you might have half a dozen or more, each with its own locator, schedule, and standards. The 811 system notifies these member utilities, but it doesn’t manage them for you. Your first step is to get organized. Keep a log of every utility notified and track their response times. Don’t be afraid to follow up if a locator is late or their markings seem incomplete. For maximum efficiency, consider bringing in a private firm that provides comprehensive utility locating services. A single-source partner can consolidate the locating process, giving you one point of contact and a unified, easy-to-read map of everything underground.

Planning for large-scale excavations

A notice of intent to excavate is the first step for any project, but for large sites, your planning needs to be more strategic. Instead of submitting one massive ticket for an entire property, consider phasing your project. Break the excavation down into manageable sections and submit separate 811 tickets for each phase. This ensures your markings are fresh and relevant to the work at hand, reducing confusion for your crew. Before you even call, a detailed subsurface utility mapping investigation can give you a complete picture of the underground infrastructure. This allows you to design your excavation plan around known utilities, preventing conflicts before they happen.

Handling high-risk areas

High-risk areas—like hospital campuses, data centers, or dense industrial sites—demand extra caution. In these environments, a utility strike isn’t just expensive; it can be catastrophic. It’s essential to identify these zones in advance and implement additional safety measures. This is where you absolutely cannot rely on 811 alone. Public locators often miss private lines or can’t detect deeper targets. Augment the 811 process with professional utility locating services that use advanced methods like Ground Penetrating Radar (GPR) to find what others miss. In the field, use soft digging techniques like vacuum excavation to visually confirm utilities before bringing in heavy machinery.

Implementing quality control checks

Don’t assume the paint on the ground is perfect. Implementing regular quality control checks is vital for maintaining a safe site and meeting compliance requirements. Start by walking the site and visually verifying the marks against your existing plans and as-builts. Do the markings make sense? Are there obvious signs of unmarked utilities, like old valve boxes or junction pedestals? Document everything with photos before, during, and after excavation. For a truly reliable record, professional GPS & GIS mapping can capture the precise location of every marked utility, creating a permanent digital map you can use for the entire lifecycle of the project.

Know Your State's Rules and Documentation

While "Call 811" is a national slogan, the system is actually a network of independent, state-run centers. This means the specific laws, response times, and even the definitions of key terms can vary significantly depending on your project's location. Assuming the process in Texas is the same as in New York is a recipe for delays and compliance issues. To keep your project on track and your team safe, you need to understand the local rules and maintain the right documentation. Here’s what you need to know to stay compliant and protect your project from unnecessary risk.

How 811 services vary by region

Every state operates its own 811 "One-Call" center, which acts as the communication hub between you and the public utility operators. Organizations like Sunshine 811 in Florida or UDig NY in New York manage all incoming locate requests for their respective territories. Because they operate independently, their processes differ. Some states may have advanced online ticket systems, while others rely more on phone calls. The legal "tolerance zone"—the area around a marked line where you must dig with caution—can also vary from 18 to 24 inches or more on either side of the marking. You can find the specific rules and contact information for your project area by checking the 811 directory for your state.

What documentation you need to keep

When you contact 811, you’ll receive a "One-Call ticket" or locate request number. Treat this number as your golden ticket—it’s the official record that you initiated the process and fulfilled your legal obligation. You should keep this ticket number in your project file, along with the date and time of your call and a list of the utilities that were notified. Once the marks are on the ground, take clear, date-stamped photos from multiple angles. This documentation creates a crucial paper trail that can protect you from liability if a dispute or an incident occurs. It proves you did your due diligence before the excavation work began.

Key insurance considerations

A utility strike is more than just an operational headache; it's a significant financial risk. Hitting a line can result in costly repairs, project-halting fines, and serious injuries, all of which can lead to insurance claims and skyrocketing premiums. Your insurance provider will expect you to follow all legally required safety protocols, and that starts with the 811 call. Failing to have a valid ticket number for your excavation site could be viewed as negligence, potentially jeopardizing your coverage in the event of an accident. Maintaining proper documentation isn't just for compliance—it's a fundamental part of your risk management strategy.

Strategies to prevent utility damage

The best way to prevent utility damage is to build a safety process that goes beyond the initial 811 call. Start by always contacting 811 a few days before you plan to dig, even for small projects. Once the public lines are marked, respect the tolerance zone and use hand tools or vacuum excavation when working near them. Keep your ticket number and photos of the marks on-site. Most importantly, remember that 811 only marks public utilities. For a complete picture of the subsurface, you need to account for private lines like power to a security gate or a water line to an irrigation system. The only way to find these is with private utility locating services.

Helpful Tools and Resources

Beyond making the call to 811, staying organized and informed is key to a safe and efficient project. The right tools can help you manage your excavation tickets, document site conditions, and access educational resources. Think of these as your support system for every dig, helping you keep track of moving parts and ensuring everyone on your team has the information they need. From ticket management software to state-specific safety training, these resources are designed to streamline your workflow and reduce risk on the job site.

Using ticket management systems

When you contact 811, you create a "ticket"—the official request for public utility members to mark their lines at your worksite. For general contractors or facility managers juggling multiple projects, tracking these tickets can get complicated fast. Ticket management systems, often offered through your state’s 811 portal, help you organize all your requests in one place. You can check the status of a locate, review communications from utility operators, and maintain a clear record for each job. This digital paper trail is invaluable for project documentation and liability purposes, ensuring you have proof of compliance for every excavation.

Mobile apps for your project

Many state 811 centers now offer mobile apps that let you submit and manage locate requests directly from your phone or tablet. This is a huge time-saver, allowing you to start the process from the field instead of waiting until you’re back in the office. These apps often include features for uploading site photos or plans to give locators better context. Using this kind of advanced technology not only streamlines your workflow but also improves the accuracy of the information you provide, leading to a more effective and reliable marking process from the start.

Online mapping tools

While 811 provides on-the-ground markings, online mapping tools can offer a broader view of a project area. Many municipalities and utility companies provide public-facing GIS maps, which can be a helpful preliminary resource. However, it's crucial to remember these maps are often incomplete or outdated and rarely show private lines. This lack of visibility creates significant challenges for risk management. That’s why professional subsurface utility mapping is so important—it fills in the gaps left by public records, giving you a complete and reliable picture of what’s actually underground before you break ground.

Where to find support

Your local 811 center is more than just a call center; it’s a hub for safety education. These organizations are dedicated to preventing utility damage and offer a wealth of resources for contractors and excavators. You can find online courses, downloadable safety guides, and even in-person public awareness and training events. If you have questions about state-specific laws, best practices for digging near certain facilities, or how to handle a specific situation, their websites and support staff are your best first stop for reliable information. Taking advantage of these free resources is a smart way to keep your crew safe and your projects on track.

Frequently Asked Questions

What's the real difference between the free 811 service and hiring a private locator? Think of 811 as the first, essential layer of safety. They coordinate with public utility companies to mark the lines they own, like the main gas, water, and power lines running along the street and up to your property's meter. A private locator handles everything else. They find the lines that the property owner is responsible for, such as power running to a security gate, a water line for an irrigation system, or fiber optic cables connecting two buildings on a campus. Private locators use advanced tools to create a complete map of everything underground, not just the public infrastructure.

Who is legally responsible for making the 811 call on a project? The responsibility for contacting 811 falls on the person or company that is actually doing the digging. If you're a property owner who has hired a general contractor, that contractor is legally required to make the call. If you're handling the excavation yourself, the duty is yours. As a project manager, you should always verify that an active 811 ticket exists for your site before allowing any work to begin. Never assume someone else has already handled it.

How soon can I start digging after I contact 811? You need to wait a specific period after submitting your request, which is usually two to three full business days, not including weekends or holidays. This waiting period is required by law and gives the utility companies enough time to send their locators to your site. Before you break ground, you must also confirm that every utility company notified on your ticket has responded, either by marking their lines or by giving an "all clear."

What should I do if I see evidence of a utility, but the area isn't marked? If you see something like a valve cover, a manhole, or a utility pedestal in an area with no corresponding paint or flags, stop. Do not assume the area is clear. It could indicate an abandoned line, an unmapped utility, or a private line that isn't covered by the 811 service. Your best course of action is to contact 811 again to report the discrepancy and call a private utility locator to investigate the situation thoroughly before you proceed with any digging.

Are the 811 markings an exact map of what's underground? No, the paint and flags provided by 811 represent the approximate location of a utility line. They are a guide, not a precise blueprint. The actual depth and horizontal position of the line can vary. This is why every state has a "tolerance zone," typically 18 to 24 inches on either side of the marks, where you cannot use mechanized equipment. Within this zone, you must dig carefully by hand to visually confirm the utility's exact location before proceeding.