Whether you need a permit to dig on your property depends on the project, but one step is never optional: federal law requires you to notify the 811 “Call Before You Dig” service before any excavation, no matter how small. A local building permit is a separate question, and it kicks in for larger projects like pools, decks with footings, retaining walls, and new underground utility service to outbuildings. Smaller work — planting a tree, setting a mailbox post, installing a fence — generally needs only the 811 call.
Two Different Requirements, Two Different Agencies
The 811 notification and a building permit serve different purposes and come from different places. Calling 811 is a federal safety requirement aimed at preventing damage to underground infrastructure. A building permit is issued by your city or county government and concerns zoning, structural codes, and land use.
You can need one, the other, or both. You never need neither.
When a Building Permit Is Required
Local building departments set their own thresholds, so the definitive answer comes from your municipal planning or building office. That said, a consistent pattern runs through most jurisdictions. Projects that almost always trigger a permit requirement include:
- In-ground swimming pools
- Decks built on footings
- Retaining walls above a certain height
- New underground utility service to a detached garage, guest house, or other outbuilding
Projects that generally do not require a permit, but still require the 811 call, include planting trees, installing mailboxes, putting in a small garden bed, or setting fence posts on a residential lot. Fences past a certain height, and any structure with a foundation, tend to cross back into permit territory.
Starting work without a required permit can bring stop-work orders, fines, and orders to tear out completed work. Call your local building department before you start; the conversation takes a few minutes and settles the question.
The 811 Call Is Never Optional
Federal law under 49 U.S.C. § 60114 directs the Secretary of Transportation to set minimum standards for state one-call notification systems and prohibits anyone from excavating in a state with a one-call system without first using that system to identify underground facilities in the work area.1Office of the Law Revision Counsel. 49 USC 60114 – One-Call Notification Systems Every state has its own one-call law built on this federal framework, and the FCC designated 811 as the nationwide number for reaching those systems.2Federal Communications Commission. FCC Designates 811 as Nationwide Number to Protect Pipelines, Utilities from Excavation Damage
The threshold for “excavation” is lower than most homeowners realize. Installing a fence, planting a tree, grinding a stump, building a deck, putting in a mailbox post, or rototilling a new garden bed all count. If you’re going into the ground with anything more aggressive than a hand trowel in a flower bed, call.
How the Process Works
The 811 service is free. You can call 811 or file a request through your state’s online one-call portal, providing your full address, the nearest cross street, a clear description of where on the property you plan to dig, the type of work, the method of excavation, and your planned start date.3US Department of Transportation. Call 811 Before You Dig
Most states require you to submit the request at least two to three business days before you plan to start. The exact window varies, so confirm with your local one-call center. Once you file, the center forwards your information to every utility company with infrastructure in the area, and those companies send locators to mark the approximate location of their buried lines.
You cannot start digging until every utility has responded. If a utility fails to respond in time, federal excavation safety rules allow work to proceed only with extreme caution and the use of detection equipment or other accepted methods to locate buried lines.4Occupational Safety and Health Administration. 29 CFR 1926.651 – Specific Excavation Requirements In practice, the smarter move is to call the one-call center back and ask them to re-notify the unresponsive utility.
What 811 Will Not Mark
This is where homeowners get a false sense of security. The 811 system locates only utility lines owned and maintained by public utility companies — the infrastructure that runs from the street to your meter or service connection point. Everything on the private side of the meter is your responsibility, and 811 will not touch it.
Privately owned buried lines that 811 ignores include gas lines running to a backyard grill or pool heater, electrical feeds to a detached garage or landscape lighting, water lines to a guest house or sprinkler system, sewer laterals running to a septic tank, and internet or security system cables. Some estimates put privately owned lines at roughly 60 to 65 percent of all underground infrastructure in the country.
If your project involves digging near any of these features, hiring a private utility locating company is worth the money. They use ground-penetrating radar and electromagnetic equipment to find lines the public one-call system won’t mark.
Reading the Markings and Respecting the Tolerance Zone
Locators mark buried lines using a standardized color code from the American Public Works Association: red for electric, yellow for gas and other flammables, orange for communications, blue for potable water, green for sewer and drain, purple for reclaimed water and irrigation, pink for temporary survey marks, and white for the proposed excavation area.5American Public Works Association. Uniform Color Code
Once lines are marked, you can’t run an excavator right up against the paint. Every state defines a “tolerance zone” around marked utilities where you must use hand tools or non-destructive methods like vacuum excavation. States are roughly split between an 18-inch and a 24-inch tolerance zone, measured horizontally from the outer edge of the buried line. Pointed spades and pick axes are generally prohibited inside that zone; the goal is to expose the line gently enough that you don’t nick it.
Markings don’t last forever either. Most states set an expiration period, commonly 10 to 30 working days, after which the marks are no longer considered reliable. If your project runs past that window or the paint fades, call 811 again for a re-mark before continuing.
What It Costs You to Skip Either Step
Skipping the 811 call exposes you to three separate categories of consequences, and they can hit at the same time.
State fines for unlawful excavation apply whether or not you damage anything. They vary widely, typically ranging from $500 to $50,000 depending on severity and prior violations. Some states escalate penalties sharply for repeat offenses.
Federal penalties come into play when pipeline facilities are involved. Civil penalties under PHMSA’s current framework can reach $272,926 per violation per day, with a cap of $2,729,245 for a related series of violations.6Pipeline and Hazardous Materials Safety Administration. Civil Penalty Summary These are aimed at commercial operators, but they signal how seriously the federal government treats excavation damage to pipelines.
Civil liability for repair costs is often the largest financial hit for homeowners. You are personally on the hook for the full cost of repairing anything you damage. Severing a major fiber-optic trunk line can run into tens of thousands of dollars. Damaging a gas main brings repair costs, emergency response expenses, and potential claims from anyone affected by a service outage. Having called 811 and followed the markings is your primary legal defense; without that documentation, you have very little to stand behind.
Skipping a required building permit brings its own costs: stop-work orders, fines, and, in bad cases, an order to tear out finished work at your own expense.
If You Hit a Line
Even careful excavators strike lines. What you do in the first few seconds matters.
If you smell gas or hear hissing, stop work immediately and move everyone away. Do not flip electrical switches, use a cell phone near the leak, or run any equipment that could create a spark. From a safe distance, call 911 and then the gas company. Do not return until responders clear the area.7Occupational Safety and Health Administration. Hazards Associated with Striking Underground Gas Lines
If your equipment contacts a buried electrical line, stay on the machine and call for help rather than stepping off while still in contact with it. Hitting a water main, sewer line, or fiber-optic cable is less immediately dangerous but still requires prompt reporting to the facility owner under federal law.1Office of the Law Revision Counsel. 49 USC 60114 – One-Call Notification Systems Call 811 to identify the affected utility and contact them directly.