Do I Need to Call 811 Before Replacing a Mailbox Post?
Yes — the area near the curb where mailbox posts go is one of the most utility-dense zones on your property. A single post hole can hit a telecom drop or electric feed that runs shallower than you'd expect.
Why a Mailbox Post Hole Is Riskier Than It Looks
A standard mailbox post hole is 6–10 inches in diameter and 18–24 inches deep. That depth range puts you squarely in the zone where cable TV drops (12–18 inches), telephone service drops (12–18 inches), and in some neighborhoods, electric service conduit (18–24 inches) run from the street-side pedestal or pole toward the house.
These near-curb utility runs are typically shorter in length than backyard utility runs, but they're denser — multiple lines often run in a narrow corridor paralleling the curb. In a neighborhood with underground utilities (as opposed to overhead poles), the service line density near the curb is highest in the entire yard.
What You'll Typically Find Near a Mailbox Location
- Cable TV/internet coax or fiber: Runs from a pedestal near the curb to the house. Often in the 10–18 inch range. Highly likely near mailbox locations in underground-utility neighborhoods.
- Telephone/DSL copper: Same path, similar depth. May be in a shared conduit with cable.
- Electric service lateral: In neighborhoods with underground electric, the service lateral runs from the transformer (often in the green box in the yard) to the meter. It passes through the front yard and may pass near mailbox locations.
- Gas service line: Runs from the street main toward the meter. Typically 18–24 inches deep and follows a direct path toward the house.
The 10-Minute 811 Process for a Mailbox Post
Mailbox post replacement is one of the simplest 811 scenarios because the dig area is tiny and precise. The locate is fast, the marks are easy to interpret, and the process is the same as any other project — just smaller scale:
Mark your intended post location with a white flag or paint dot
One flag at the exact post location. This gives the locator a precise target.
Call 811 or submit online — takes under 5 minutes
Describe as: "Replacing mailbox post, single 6-inch diameter hole approximately 20 inches deep, located [describe distance from curb and address]." Simple, fast, free.
Wait 2–3 business days
Plan ahead — don't remove your old post until you have the new location cleared.
Review marks and adjust post location if needed
If marks fall within 18–24 inches of your planned post location, shift the post along the mailbox run until you're clear. Most mailbox mounting positions have some flexibility.
My mailbox is right at the edge of my property, near the road. Is the utility company responsible for lines there?
Can I use a post-pounder to drive a metal mailbox post without calling 811?
Related Guides
Fence Posts
Larger post installation guide — same process, more posts.
Driveway Projects
Other near-curb work with utility risk.
Wait Times by State
How long to wait in your state before digging your post hole.