Before You Dig in PA: 811 Rules, Tolerance Zone, and Fines

Before you dig anywhere in Pennsylvania, you have to call PA 811 — the PA One Call System — at least three business days ahead of the work.¹ The rule applies to contractors, utility crews, and homeowners equally. The call is free, takes a few minutes, and lets utility companies mark buried lines on your property before a shovel or auger goes in. Skip it and you can face fines up to $50,000 plus full liability for whatever you hit.

Who Has to Call

Pennsylvania’s Underground Utility Line Protection Act, Act 287 of 1974 as most recently amended by Act 127 of 2024, defines an “excavator” as any person performing excavation or demolition, whether for themselves or for someone else.¹ That includes a homeowner installing a fence, planting a tree, or setting a mailbox post. If your project moves earth with powered equipment or explosives, the statute treats you as an excavator.

A couple of narrow activities sit below the threshold: agricultural tilling under eighteen inches deep and minor routine road maintenance under eighteen inches from the cartway or shoulder edge.¹ Everything else triggers the call.

The Three-Business-Day Rule

You must contact PA One Call between three and ten business days before you plan to dig. The count starts the business day after your request comes in, and you cannot begin work until the third business day has passed.¹ Requests filed on a Saturday, Sunday, or holiday get processed the next business day. If you file, then step away from the site for more than two business days, you need to notify PA One Call again before resuming.²

Large or unusually involved jobs count as “complex projects” under Act 287 and require at least ten business days of notice instead of three.¹ Most residential and small commercial jobs run on the standard three-day timeline.

What to Have Ready Before You Call

Have the county, municipality, and street address of the work site in hand. PA One Call needs a clearly bounded area with identifiable reference points, such as nearby landmarks or the specific part of the property involved.³ Also know the type of work and how deep you expect to go. Different utilities sit at different depths, and better information means faster, more accurate locates.

When it’s hard to describe the boundaries of your dig site in words, Act 287 directs you to pre-mark the area on the ground with white paint or white flags.¹ That way locators mark only the area you plan to disturb rather than the whole property.

How to File the Request

You have two options. Call 811 and a representative will walk through the project details, or use the PA One Call web portal to enter the same information yourself with a digital map to confirm the location.³ The system generates a serial number for each political subdivision your project crosses. Keep that ticket number accessible at the work site for the duration of the job.

Once your request is filed, utility companies in the area are notified automatically. They have until the end of the second business day after PA One Call received the request to respond, or until the day before your scheduled start if you specified a later date.⁴

Checking Responses Before You Dig

PA One Call runs an automated response system called KARL (Know All Responses by Logging in) that shows how each utility has responded to your ticket. You can check it online or by phone. Each utility will post one of a few outcomes: the site has been marked, no conflict exists in the area, or more time is needed. Do not start digging until every utility on your ticket has responded.

If a utility misses its deadline, you must renotify PA One Call about the unresponsive company. After renotification, the facility owner has two hours to communicate its line locations to you directly and, if necessary, come mark them on site. If nothing sufficient comes through after three hours, you may proceed, but only with due care and only within the tolerance zone rules described below.¹ A missing response does not mean no lines are there.

What the Paint and Flag Colors Mean

Locators use the American Public Works Association uniform color code, and each color signals a specific type of buried line:⁵

Red: electric power lines, cables, and lighting conduit
Yellow: gas, oil, steam, and petroleum lines
Orange: communication, alarm, and signal lines (phone, cable, fiber)
Blue: potable water
Green: sewers and storm drains
Purple: reclaimed water, irrigation, and slurry lines
Pink: temporary survey markings
White: proposed excavation area (your pre-markings)

Knowing the colors matters once you’re digging. Yellow paint means gas, and how you handle resistance near yellow is different from how you handle it near blue.

The Tolerance Zone

Pennsylvania law defines the tolerance zone as the horizontal space within eighteen inches on either side of the outer edge of a marked line.¹ Think of a thirty-six-inch-wide corridor centered on the paint. The mark tells you roughly where the line runs; the actual pipe or cable could sit anywhere inside that corridor.

Inside the tolerance zone, the statute requires prudent techniques to find the exact position of the line before you cut through: hand-dug test holes, vacuum excavation, and similar careful methods.¹ Heavy machinery inside the zone without verifying the line first is how most strikes happen and how most violations get written up.

What 811 Doesn’t Cover

PA One Call locators mark utility-owned lines, but they typically stop at the meter or the point where the utility connects to your property. Customer-owned lines past that point are your responsibility, including service lines running to the house, outdoor lighting wires, pool electrical connections, gas lines to a grill, and invisible pet fences.⁶

If your dig is near any of those, consider hiring a private utility locator. PA One Call lists private locating companies on its website. They use electromagnetic and ground-penetrating radar tools to trace lines the public system won’t mark. That fee is far smaller than the cost of repairing a severed gas line to a pool heater.

Emergency Digging

Act 287 defines an emergency as a sudden or unforeseen occurrence involving a clear and immediate danger to life, property, or the environment, including serious breaks or defects in a facility owner’s lines.⁴ In an emergency, the three-day rule does not apply. You can begin work immediately, but you still have to notify all facility owners through PA One Call as soon as possible, whether before, during, or after excavation, depending on the situation. The exemption is from the timeline, not from the notification itself.

If You Hit a Line

Stop work at once. Under Act 287 you must report any break, leak, dent, gouge, or damage to a facility owner’s line the moment you discover it, even if it looks minor.¹ A nick on a gas pipe’s coating can cause corrosion that turns into a leak months later.

If the damage releases flammable, toxic, or corrosive gas or liquid that endangers life, health, or property, call 911 and the facility owner immediately. The statute also requires reasonable measures to protect yourself, your crew, bystanders, and the surrounding property until responders arrive, and it directs you to stay on site to share information that helps them respond safely.¹

If a strike causes personal injury or property damage to anyone other than you or the affected facility owner, you have ten business days to file an incident report with the Pennsylvania Department of Labor and Industry.¹

Who Pays When Something Gets Hit

An excavator who followed Act 287 and was not otherwise negligent is not liable for damage to the facility owner’s lines.¹ Compliance is the shield. If you called 811, waited the required days, checked responses, worked prudently inside the tolerance zone, and still hit a line, the facility owner bears the cost.

When both sides share fault, repair costs are split in proportion to each party’s contribution.¹ If the facility owner marked correctly and you dug through the marks anyway, the full repair bill is yours. Fixing a single gas main can run tens of thousands of dollars, and utilities can also pursue costs related to service interruption on top of the physical repair.

Fines for Not Calling

The Pennsylvania Public Utility Commission enforces Act 287 and can issue warnings, compliance orders, or administrative fines. Penalties run in two tiers:¹

Standard violation: up to $2,500 per violation.
Violation causing injury, death, or property damage of $25,000 or more: up to $50,000 per violation.

Unpaid fines accrue an added $100 per day, capped at $5,000. The commission can also require completion of a damage prevention educational program within sixty days, and missing that deadline triggers another $100-per-day penalty with the same $5,000 cap.¹ These administrative fines are separate from civil liability for the damage itself, which is often the bigger number.

1
Pennsylvania One Call System. Underground Utility Line Protection Law
2
Pennsylvania One Call System. Frequently Asked Questions
3
Pennsylvania 811. Pennsylvania 811 Excavators
4
Pennsylvania Department of Labor and Industry. Underground Utility Line Protection Law Act 287 of 1974
5
American Public Works Association. Uniform Color Code
6
Pennsylvania One Call System. Homeowners