Call 811, survey your line, and other things to do before you dig

Published April 18, 2026 by the FenceCalc team

Foot pressing a shovel into garden soil before digging fence post holes safely — Photo via Pexels

My uncle hit a gas line with a post auger in 2019. He was digging a fence post in his own back yard, 14 feet from the house, in a spot he'd dug through for gardening a hundred times. The gas line was a feeder from a neighbor's service that cut diagonally across his lot, unmarked on any deed document he'd ever seen. Utility crews, fire trucks, and a $6,800 repair bill later, he was still digging that fence. But everything changed about how he started the next project.

Here's the pre-dig checklist. Do it every time. Even if you've dug in the spot before. Even if the fence is a small replacement. Even if it feels like overkill.

Step 1, call 811 at least 48 hours before

811 is the national "call before you dig" service. It's free. You call or submit online, tell them you're planning to dig, give them the address and a rough description of where. Within 48 hours, utility companies come out and mark buried lines with spray paint and flags.

Color codes:

Red: electric
Yellow: gas, oil, steam
Orange: communication (phone, cable, fiber)
Blue: potable water
Green: sewer and drainage
Purple: reclaimed water, irrigation
Pink: temporary survey markings
White: the area you're planning to dig (you paint this before they come out)

Always paint your work area in white before the 811 call so the utility crews know exactly where you need marks. A can of white spray paint from Home Depot costs $6 and makes the marks 10x more accurate.

811 is federal law. Fines for skipping it range from $1,000 per incident in rural states to $20,000+ per incident in California. If you hit a utility line without calling 811, your insurance probably won't cover the repair.

Step 2, find your actual property line

This is where most boundary fights start. Homeowners assume they know where the line is, the neighbor assumes the same, and the fence gets built a foot into someone else's property. Then the real estate lawyers get involved.

Three options, in order of reliability:

Professional land survey. $400-$800 for a typical residential lot. A licensed surveyor comes out, finds the corner pins (usually iron rods or concrete monuments), and flags the boundary line. This is the gold standard. If you have any neighbor friction, spend the money.

Find existing corner pins. Most residential lots have iron pins at each corner, buried 4-8 inches below grade. A metal detector and a screwdriver usually finds them. Older lots may have pins missing. If you find all four, you can string a line and measure your fence run accurately.

Plat map only. The least reliable. Pull your property's plat from the county assessor website. Dimensions are usually accurate but placement relative to physical features (driveway, house, trees) can be off by several feet. Fine for rough planning, not for fence installation.

The $600 survey is the single cheapest item in the entire fence-building budget if it prevents a boundary lawsuit. Pay for one if there's any chance your neighbor might dispute the line later.

Step 3, talk to your neighbors before you build

A fence on a shared property line affects the neighbor. Even if you're not legally required to get their approval, the courtesy of a pre-build conversation prevents 80 percent of fence disputes.

What to cover in the conversation:

Where exactly the fence will sit (show them your survey if you have one)
What it'll look like (material, height, color)
When you're starting and roughly how long it'll take
Which side faces them (this matters for wood fences with rails on one side)

Ask if they'd like to share costs. Many states have laws allowing shared-cost fences between neighbors on a common boundary. Even if you're paying for the whole thing, offering to split often gets you an ally for the project.

Document the conversation. Send a polite follow-up text or email summarizing what you discussed. "Hi John, thanks for chatting earlier about the fence. As discussed, I'll be installing a 6ft cedar fence on the property line this April, with the smooth side facing your yard. Let me know if you have any concerns before I start." Now you have a record.

Step 4, check setback requirements

Most cities require fences to sit a specific distance from the property line itself, not directly on it. 6-12 inches is common. This is called the setback requirement.

Some cities, particularly in the Southwest and California, have specific front-yard setbacks that differ from side and rear yards. A 6ft fence legal in the back yard might need to sit 3-5 feet back from the front sidewalk.

Corner lots have vision-triangle rules (mentioned in the permit post) that limit fence height within 20-30 feet of a street corner.

These rules are in the same city planning document that lists permit requirements. Read both before you measure.

Bonus, photograph everything before you start

Walk the property line with your phone and take 20-30 photos. Existing fence condition, existing landscaping, the neighbor's side, any obvious property markers, any damage or irregularities. Timestamp the photos.

This documentation protects you if a neighbor later claims your fence damaged their landscaping, or if the city inspector claims your install damaged public property. Photos with timestamps are hard to dispute.

What happens when you skip the checklist

Real stories from people I've talked to:

"My contractor started digging without 811. Hit a Comcast cable line. Cable was out in the whole neighborhood for 48 hours. We got the bill for $2,400."

"Built the fence 11 inches into my neighbor's lot because we used a rough estimate instead of finding the pins. He sold the house three years later. New owner commissioned a survey. Found the encroachment. We tore out and rebuilt 11 inches toward my side. Total cost: $4,200."

"Skipped the neighbor conversation. Built a 6ft privacy fence facing their driveway. Neighbor sued claiming the shadow killed their grass. Settled for $1,800 plus landscape restoration costs."

Every one of these was preventable with the 45 minutes and $0 to $600 of the pre-dig checklist.

Use the calculator

Before calling 811, get your total linear footage dialed in. Use the FenceCalc estimator to pick material and height, then measure your actual run against that plan. A clear plan makes the 811 call easier ("I'm digging post holes along the east and north property lines, roughly 75 feet in each direction, to a depth of 30 inches").