Fence permits and height rules in Twin Falls (what to check first)

Inside Twin Falls city limits, you don’t need a building permit for a fence that is 7 feet tall or shorter. A fence over 7 feet needs one. You can usually build right up to your property line, but the fence has to stay 3 feet tall or lower inside the sight triangles at street corners, alleys and driveways, and it has to keep 3 feet of clear space around fire hydrants.

That covers most backyard projects. The details below come from the City of Twin Falls Building Department’s fence handout and the city zoning code. Rules change, so confirm with the city before you set posts.

Do I need a permit to build a fence in Twin Falls?

For most homeowners, no. The city’s Fences and Sight Obstructions handout says: “If the fence is to be 7 foot or less in height no building permit is required. If the fence is to be over 7 foot in height a building permit is required.”

If you do need a permit, the handout lists what to bring:

• A site plan showing where the fence will go on the property.
• Structural plans showing the type of post, fencing material and construction method.
• Details showing how deep the posts go into the ground or concrete.
• The height of the fence.

There’s one big exception to the “no permit” rule. If your property is in a flood zone, the city requires a Floodplain Development Permit through the Engineering Department, even when no building permit is needed.

How tall can my fence be?

Outside the sight triangles described below, the handout says a fence “can be built to a height of 7 feet, without a building permit.” It doesn’t set a separate lower limit for front yards. The limit that catches most people is the 3-foot rule near streets, alleys and driveways.

A few other places have their own limits. The city’s Canyon Rim overlay zone, along the Snake River Canyon, caps fences at 7 feet. If your lot backs up to the canyon rim, ask the Planning and Zoning office which overlay rules apply.

What are the corner lot and driveway rules?

These rules exist so drivers can see kids, bikes and cars. Inside each triangle below, the fence can’t be taller than 3 feet. Twin Falls City Code 9-9-16 also bans anything on public or private property that blocks a driver’s view at an intersection and creates a traffic hazard, which covers hedges and shrubs too.

• Street corners: Measure 40 feet along the face of the curb on each street from where the curb lines meet (or from the pavement edge if there’s no curb). Connect those two points. That’s the 40-foot sight triangle.
• Alleys: Where an alley meets a street, measure 40 feet along the curb or pavement edge and 15 feet along the alley, then connect the points.
• Driveways: Facing your property from the street, measure 100 feet along the face of the curb and 10 feet along the left edge of the driveway, then connect them. On the right side, it’s 125 feet along the curb and 10 feet along the driveway edge.

The driveway triangles are long, and they can reach across a neighbor’s frontage. If there’s no curb in front of your home, the handout says to call the City Engineering Department to get the future curb line before you measure.

Can I build my fence right on the property line?

Yes, in most cases. Section 10-3-2 D of the 2026 Twin Falls zoning code says walls, fences and hedges “may be permitted up to the property line” when they don’t conflict with the sight-obstruction rule. It also says they can’t go in a public right-of-way unless you first get a Right of Way Encroachment Agreement from the city.

That second part trips people up. Your property line often isn’t where the sidewalk ends or where your lawn stops. Before you build near a street:

• Find your property corner pins, or hire a surveyor if you can’t.
• Check your plat or title documents for utility or irrigation easements. A fence in an easement may have to come down if a utility needs access.
• Talk to the neighbor before building on a shared line. It prevents most fence disputes.

What about fire hydrants and utility boxes?

The Fire Department requires a clear area at least 3 feet wide on all sides of a fire hydrant. No fences, trees, shrubs or decorations in that space. For power boxes, phone pedestals and other utility equipment, the handout says to check with the utility company about setbacks.

Do I need to call 811 before digging fence posts?

Yes. Idaho’s Digline rules apply to homeowners digging on their own property, not just contractors. You need to give notice through 811 at least 2 business days, but no more than 10 business days, before you dig. The service is free.

A few practical tips:

• Mark your fence line with white paint or flags before you call, so locators know where you plan to dig.
• Hand dig when you’re within 24 inches of a marked line.
• 811 covers lines owned by utility companies. Your own sprinkler pipes, pressurized irrigation lines and yard lighting wires usually aren’t marked, so find those yourself.

Post depth matters too. The City of Twin Falls uses a 24-inch frost depth for footings. Fence posts set well below that tend to hold up better through freeze and thaw. Our guide to fence materials that stand up to Magic Valley wind covers post depth and concrete in more detail.

What if I live outside Twin Falls city limits?

The rules above apply only inside the City of Twin Falls. Other towns set their own rules:

• Unincorporated Twin Falls County: Planning, zoning and building permits go through Twin Falls County Community Development Services. The county zoning code doesn’t have the same fence handout the city does, so call before you build, especially on a corner or along a county road.
• Kimberly, Filer, Buhl, Jerome and other towns: Each city has its own code. Call city hall or the building office in your town.
• Area of city impact: Some land just outside city limits falls under special city-county agreements. Ask the county which rules apply to your parcel.

Can my HOA be stricter than the city?

Yes, and many are. Subdivision CC&Rs can limit fence height, material, color and style, and some require written approval from an architectural committee before you build. A fence that passes city rules can still break your HOA’s rules. Read your CC&Rs and get any approval in writing before you order materials.

What should I check before I build a fence?

• Confirm whether you’re inside Twin Falls city limits, in the county, or in another town.
• Check the height: 7 feet or less needs no city building permit.
• Measure sight triangles at corners, alleys and driveways, and keep the fence 3 feet or lower inside them.
• Check whether you’re in a flood zone.
• Find your property pins and any easements. Stay out of the right-of-way.
• Keep 3 feet clear around fire hydrants.
• Read your HOA rules and get approval in writing.
• Call 811 at least 2 business days before digging.
• Call the city’s Building Safety Department to confirm the current rules.

If you’d rather not handle all of this yourself, our fence installation team in Twin Falls checks property lines, sight triangles, HOA rules and 811 locates as part of planning the job. Spring is the busiest season for fence work, so see our Magic Valley project calendar for timing tips.

How does Zircon handle fence rules on a project?

We’re a general contractor, so we plan the fence, check the rules that apply to your lot, call in the locate and schedule the crew we vet and manage. You get a written estimate that spells out height, material and fence line before any posts go in. Learn more about our fencing service, or request a free estimate and we’ll walk the property with you.