Twin Falls Fence Guide: Permits, 811 & Wind (2026)

Updated October 25, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.

Quick reference

Topic	What to know	Source
Building permit	Not needed for fences 7 ft or less; required over 7 ft	City of Twin Falls fence handout
Sight triangles	Fences limited to 3 ft at corners, alleys and driveways	City of Twin Falls fence handout
Fire hydrants	3 ft clear on all sides	City of Twin Falls fence handout
Frost depth	24 inches	City of Twin Falls residential design criteria
Design wind	115 mph gust, Exposure B (C in some areas)	City of Twin Falls residential design criteria
Before digging	Locate request 2 to 10 business days ahead; marks good up to 3 weeks	Idaho DOPL Damage Prevention
Contractor registration	Jobs over $2,000; $300,000 liability minimum	Idaho DOPL
Canal easements	Written permission needed for fences on irrigation easements	Idaho Code 42-1209
Lawful fence	At least 4 1/2 ft high, bottom no more than 20 in. up	Idaho Code 35-101

How do climate and ground affect a fence here?

Twin Falls sits at the south rim of the Snake River Canyon at about 3,700 feet, with a semiarid climate: roughly 11 inches of precipitation and 24 inches of snow in an average year, and recorded extremes from 104 degrees to 23 below zero. The city's residential design criteria use a 24-inch frost depth, a 115 mph gust wind speed with Exposure B in most of the city and C in some areas, and a "severe" weathering rating. Under the farmland, Idaho State University's digital atlas describes the canyon at Twin Falls as cut into Quaternary basalt. In practice, that means posts deep enough to stay below frost, a plan for rock in post holes, wind bracing on solid fences and gates, and a good finish on wood.

Do I need a permit in Twin Falls?

Inside city limits, a fence 7 feet tall or less doesn't need a building permit, according to the city's fences and sight obstructions handout; a taller fence does, and the application asks for a site plan, post and material details, post depth and height. Fences can go on the property line. Even without a permit, three limits apply. At a street intersection, fences can't exceed 3 feet inside a triangle measured 40 feet along each curb line. At an alley, the triangle is 40 feet along the street and 15 feet along the alley. Beside a driveway, the triangle runs 100 feet along the curb on the left and 125 feet on the right, by 10 feet along the driveway edge. Fire hydrants need 3 feet of clearance on all sides. In a mapped flood zone, the city's Engineering Department requires a floodplain development permit.

What about Kimberly, Jerome, Buhl and rural land?

Kimberly, Filer, Buhl, Hansen and Jerome are separate cities with their own codes, and the Twin Falls handout doesn't apply in them. Unincorporated land in Twin Falls County and in Jerome County follows each county's rules. Call the city or county office for your address, or have your contractor confirm it.

Do HOA covenants matter?

Often as much as city rules. Many subdivisions set fence height, material and color, and some require architectural approval first. An HOA can enforce its covenants even when the city has no objection, so get the current rules before collecting quotes.

Who has to call 811?

Whoever digs. Idaho's damage prevention rules call for a locate request at least 2 and no more than 10 business days before excavation, with the dig area outlined in white paint as Idaho Code 55-2205 requires. Locate marks are generally good for up to 3 weeks. Water and sewer owners mark only to the meter, so the service line to the house, sprinkler lines and power to a shop need a private locator. Stay at least 24 inches from a marked line unless you're hand digging with care.

Does a fence contractor need to be registered?

In most cases. DOPL requires contractor registration for construction jobs over $2,000 in labor and materials that aren't otherwise exempt. Registration requires general liability insurance of at least $300,000 and proof of workers' compensation coverage or a statement explaining why it isn't required. Registered contractors must show their number on contracts, advertising and permits. Owners doing their own work on their own property are exempt if they don't plan to sell within 12 months.

Can I fence along an irrigation canal?

Not on the canal's easement without permission. Idaho Code 42-1209 bars fences, gates and other encroachments on the easements of irrigation districts, canal companies, lateral ditch associations and drainage districts without the entity's written permission. The Twin Falls Canal Company alone runs more than 100 miles of main canal and more than 1,000 miles of side canals, so this comes up often around Twin Falls.

What is a lawful fence?

Idaho Code 35-101 defines a lawful fence as at least 4 1/2 feet high, with the lowest part no more than 20 inches above the ground and the space between sufficiently subdivided. If you keep animals or share a division fence, ask your contractor to build to that standard.

Questions to ask a fence contractor

What is your Idaho contractor registration number?
How deep will posts go, and what happens if a hole hits rock?
Who submits the 811 locate request?
Does my fence need a permit, and have you checked my HOA and any canal easement?
What does the warranty cover, and for how long?

Common questions

Do I need a permit for a fence in Twin Falls?

Inside city limits, only for fences over 7 feet, per the city's fence handout, plus a floodplain permit in flood zones. Other cities and the counties have their own rules.

How deep should fence posts go in Twin Falls?

The city's design criteria use a 24-inch frost depth. Ask your contractor how deep they set posts for your fence height and wind exposure.

How far ahead do I call 811 in Idaho?

At least 2 and no more than 10 business days before digging. Marks are generally good for up to 3 weeks.

Twin Falls fence guide (2026)