Call 811 Before You Dig: What Every DIYer Needs to Know
811 is the free, national call-before-you-dig service that gets your buried utility lines marked before you break ground. Using it is the law in every US state, and for a sprinkler install it is the single most important safety step you will take.
Any project that involves trenching — and a sprinkler system involves a lot of it — means putting a shovel or a trencher into ground that may hide gas, electric, water, and communication lines. You cannot see them, and hitting one can cause serious injury, a costly outage for the whole neighborhood, or worse. The 811 system exists to prevent exactly that, and it costs you nothing but a couple of days of lead time.
What 811 is
811 is a nationwide phone number and online service that connects you to your state's one-call center. You tell them where you plan to dig, and they notify the utility companies with buried infrastructure in that area. Those utilities then send locators to your property to mark where their lines run. The service is free to you as a homeowner, and it is designed to be used by DIYers, not just contractors.
Why it is essential — and required
Calling 811 before you dig is not a courtesy or a best practice you can skip on a small job. It is legally required in every US state, and digging without valid locates can expose you to liability for any damage you cause. More importantly, it is about safety: striking an electric line or a gas line during a routine sprinkler trench is a genuine hazard to your life. No sprinkler zone is worth that risk.
Safety: Never dig — not even a shallow trench or a single valve-box hole — until you have submitted an 811 request and every expected utility has marked its lines. If you are ever unsure whether marks are complete, stop and confirm with the one-call center before your shovel goes in. This step is not optional and it is not negotiable.
How the process works
The process is straightforward, but it takes a little planning:
- Request early. Call 811 or submit a request online, typically two to three business days before you plan to dig. Rules vary by state, so allow the full lead time.
- Describe the area. Tell them your address and mark or describe where you will be digging. Many homeowners pre-mark their planned dig area in white so locators know where to focus.
- Wait for the marks. Utility locators visit and mark their buried lines with color-coded spray paint and flags. Different colors mean different utilities.
- Confirm everything responded. Make sure each expected utility has come out before you start. If one is missing, follow up rather than assuming there is nothing there.
- Dig carefully around the marks. Respect the marks for the life of your project, and re-request if the marks fade or expire before you finish.
The APWA color code
Utility locates use a standardized set of colors defined by the American Public Works Association. Learning them lets you read your yard at a glance:
| Color | What it marks |
|---|---|
| Red | Electric power lines, cables, and conduit |
| Yellow | Gas, oil, steam, and other flammable material |
| Orange | Communications — telephone, cable TV, fiber, alarm lines |
| Blue | Potable (drinking) water |
| Green | Sewer and drain lines |
| Purple | Reclaimed water, irrigation, and slurry lines |
| Pink | Temporary survey markings |
| White | Your proposed excavation — where you plan to dig |
Digging safely near the marks
Once your utilities are marked, treat the area around each mark as a no-machine zone. Most states define a tolerance zone — commonly about 18 to 24 inches on either side of a marked line — where you must dig by hand or use only careful, non-mechanized methods to expose the line before continuing. Keep your trencher and any powered equipment out of that zone. If you need to cross a marked line, hand-dig down to find it first, then work around it.
Note: Marks are for reference, not a guarantee of exact depth. A line can sit shallower or deeper than expected, so stay cautious even when you think you are clear of the tolerance zone.
What 811 does and does not locate
This is the gap that catches many DIYers. The 811 service locates the utility companies' lines up to the point where they enter your property or meter. It does not locate private lines that you or a previous owner installed — and that includes your existing sprinkler pipes, low-voltage landscape lighting, a gas line running out to a grill or pool heater, a well line, or an invisible pet fence. Those are your responsibility to find and avoid.
So when you are trenching for sprinklers, remember that other buried features on your own property will not be marked. Dig thoughtfully in areas where you know or suspect private lines run, and hand-dig where you are uncertain. If you are planning your trench routes, our guides to designing a sprinkler system and installing a sprinkler system show how the trenches, valves, and point of connection come together — and you can map your dig routes when you design your system from a satellite photo.
Plan the dig, then make the call
811 is free, it is fast, and it is the law — there is simply no reason to skip it. Lay out where your trenches will run, submit your request a few days ahead, and let the locators do their part before you start. When you are ready to plan those routes, design your system from a satellite photo and dig with confidence.