Building on a foothill lot in Sandy or Draper

Why the foothills have extra rules

The views are the draw. The ground is the catch.

• The Wasatch fault. The Utah Geological Survey says the Salt Lake City part of the fault makes a magnitude 7 earthquake about every 1,350 years on average, and the last one was roughly 1,300 years ago. In its scenario study, the ground along the East Bench split with a step averaging about 6 feet. The USGS gives the Wasatch Front a 43% chance of a magnitude 6.75 or larger quake in the next 50 years.
• Debris flows. The fans of rock and soil at canyon mouths are popular places to build. The UGS says debris flows there can push houses off their foundations.
• Landslides. The UGS says nearly all recent Utah landslides were old slides moving again, and it recommends a site study for all new building.

This is not just theory. In April 2023, two Draper homes slid down a hillside, KSL reported. They sat in a development where the city had allowed building on slopes of 30% or steeper.

Sandy's rules

Most of Sandy's foothill land sits in its Sensitive Area Overlay. The city's own requirements say:

• Slopes of 30% or more are a protected hillside and stay natural.
• Homes sit an average of 20 feet back from that hillside, and no closer than 10 feet at any point.
• Cuts or fills over 10 feet need Planning Commission approval.
• Retaining walls 4 feet or taller need engineer-stamped calculations.
• The grading and drainage plan must be stamped by a Utah-licensed architect or civil engineer.
• A geological report finds any faults and sets how far back the house must sit.

Sandy also has its own wildfire rule in state law. In the areas Sandy marks as wildland-urban interface, homes must be built with fire-resistant construction as the Fire Marshal decides.

One more check: some foothill addresses near the canyon mouths are in unincorporated Salt Lake County, not Sandy. The county has its own rules, so confirm which one your lot is in.

Draper's rules

• The 30% line. Draper's city manager told KSL in 2023, "Our code says you can't build on something that's more than 30% slope." The planning commission can make exceptions when the hazard is fixed to city standards.
• Soil report first. Draper will not take plans for a new home until a geotechnical report for the lot is reviewed and approved.
• Fault study areas. Draper's standards, updated in December 2025, call for a fault study within 300 feet on the low side and 150 feet on the high side of a mapped fault. A single-family home must sit at least 15 feet from a fault, and often more once the engineer runs the numbers.
• Extra steps in hazard areas. A scoping meeting with the city, a land disturbance permit before any digging, and a notice recorded on the property that shares the hazard report with future owners.
• Wildfire. Draper set up a Wildland Urban Interface area by ordinance in December 2025.

Utah's wildfire law

A state law that took effect January 1, 2026 (House Bill 48) requires Utah cities and counties to adopt and enforce the state's wildland-urban interface building code. If your lot is on the edge of the mountains, expect rules on roofing, siding and the space around the house.

What a slope adds to the cost

• Retaining walls. Fixr says walls on sloped sites run $40 to $200 per linear foot, often with regrading. Anything 4 feet or taller needs an engineer in Sandy.
• Soil testing. A basic soil survey with two borings and a report is about $1,400 to $1,600, with results in 5 to 10 business days, per Fixr. A full hillside hazard study with fault and slope work costs more.
• Time. Studies, scoping meetings and city review all come before a building permit. Start them early.

How Alpha Homes starts a foothill build

Tanner walks the lot with you before anything is drawn. From there, Alpha Homes brings in the engineer and the geotechnical work, and handles the permits and inspections with your city, so slope, fault and wildfire rules shape the plan from day one instead of surprising you halfway through.

Keep reading

• What does it cost to finish a basement in Utah?
• Do you need a permit to finish a basement in Sandy, Utah?
• Taking out a wall to open up your kitchen