Do You Have to Call Diggers Hotline Before Installing Fence Posts?
Yes. Wisconsin law requires anyone digging — including a homeowner digging fence-post holes in their own yard — to notify the state's one-call system before starting. This isn't a local ordinance that varies by town the way permit and height rules do; it's a single statewide statute that applies the same way in Eau Claire, Chippewa Falls, Altoona, Menomonie, Lake Hallie, and Fall Creek alike.
The statute
Wis. Stat. § 182.0175(2)(am)1. requires an excavator to notify the one-call system at least 3 working days before starting an excavation. "Excavator" is defined broadly enough to cover digging, augering, or otherwise disturbing the ground — which includes digging or augering fence-post holes, not just larger construction or utility work. The requirement doesn't depend on how many holes are being dug or how deep they are; a single post hole triggers the same notice requirement as a much larger project.
Once notified, the affected utilities have their own window to come out and mark the location of any underground lines with paint or flags. Wis. Stat. § 182.0175(2)(as)1. then requires the excavator to maintain a minimum clearance of 18 inches from a marked line while digging. That 18-inch figure is a clearance distance from the marked line, not a maximum depth for a post hole — it tells you how far to stay away from what's been marked, not how deep you're allowed to dig overall.
Why this applies to a homeowner's own fence project
It's easy to assume a one-call notification requirement is aimed at contractors, utility crews, or large excavation projects, and doesn't apply to a homeowner digging a few post holes in their own backyard. The statute doesn't draw that distinction. "Excavator" covers anyone doing the digging, and fence-post holes are exactly the kind of shallow, close-to-the-surface digging that damages buried gas, electric, water, or communication lines most often. Utility lines are frequently buried shallower than people expect, and a homeowner with a post-hole digger or an auger can hit one just as easily as a contractor with larger equipment.
What the notice process looks like
Notifying the one-call system before digging is free and doesn't require a permit application of its own — it's a separate step from any municipal fence permit covered elsewhere on this site. The practical sequence is:
- Submit the excavation notice at least 3 working days before the planned dig date, identifying the property and the general area where digging will happen.
- Wait for the notified utilities to mark their lines in the area (paint, flags, or stakes).
- Maintain the 18-inch clearance required under § 182.0175(2)(as)1. once lines are marked.
- Dig only after marks are in place and the notice window has passed.
Skipping this step doesn't just carry statutory risk — it's also how a fence project turns into an expensive utility repair, a lost afternoon waiting for an emergency locate crew, or in the worst case a safety incident from hitting a gas or electric line.
What "3 working days" actually means
"Working days" generally excludes weekends and legal holidays, which means the practical waiting period is often longer than 3 calendar days once a weekend or holiday falls inside the window. A notice submitted on a Thursday, for example, may not clear its 3-working-day window until the following Wednesday once a weekend is factored in. Planning a project's start date around the calendar-day count alone, rather than the working-day count, is a common way homeowners end up starting to dig a day or two earlier than the statute actually allows.
What the marks on the ground mean
Once utilities respond to a notice, they typically mark the location of buried lines with paint, flags, or stakes, often color-coded by utility type (a locate service or the one-call center can confirm what each color on a given property represents). These marks are temporary and can fade or be disturbed by weather, mowing, or other yard activity, so a fence project that gets delayed for more than a short stretch after marking may need a fresh notice and a fresh set of marks rather than relying on marks placed weeks earlier.
If a marked line runs through the planned fence line
Sometimes a utility mark turns up exactly where a post was planned. When that happens, the right move is to adjust the fence layout — shifting a post location, changing spacing, or in some cases routing around the marked line entirely — rather than digging through or immediately next to a marked line and hoping for the best. A professional who works with these constraints regularly can usually adjust a layout without compromising the fence's overall design or the property's applicable height and setback rules.
This is separate from a municipal fence permit
A city or village fence permit (covered on the per-town permit page linked below) and the statewide one-call notice are two different requirements that both apply to the same project. Getting a fence permit from the city doesn't satisfy the one-call notice, and vice versa — a homeowner needs to handle both, on their own timelines, for the same fence installation.
Where this fits into the bigger picture
The one-call notice and clearance requirements are one piece of the code picture that applies to fence installation everywhere in the Chippewa Valley, alongside the permit, height, and setback rules that vary by town. For the full breakdown, see fence installation.