Building permits, zoning and land rules in Iron County, Utah

At a glance

Building permit

Required for structural, electrical, plumbing or mechanical work; the narrow accessory-building exception ends above 200 square feet¹

Zoning

Iron County zoning and subdivision review cover unincorporated land; use the county zoning map with the parcel number to identify the district²⁶⁷

Septic

A permit and approved design are required; unsewered residential subdivision lots generally must be at least 5 acres⁵⁸⁹

RV living

Not for year-round living; temporary and seasonal occupancy depend on the zoning district and county conditions¹⁰¹¹¹²

Tiny home

Wheeled tiny homes and park models are travel-trailer-park uses; permanent-foundation manufactured or modular tiny homes are listed for R4K¹³

Owner-builder

Available with conditions; the form does not remove permit or inspection requirements¹⁴

Private well

A valid water right and State Engineer permission are required before regulated well construction¹⁵

Driveway access

The first public-road access for a new home is approved with its building permit; additional access needs an encroachment permit¹⁶

Who to call

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Do you need a building permit in Iron County, Utah?

Yes. Iron County requires a building permit for structural, electrical, plumbing or mechanical work that the county administers, including new construction, additions, remodels and utility upgrades.¹ An accessory structure no larger than 200 square feet can avoid a building permit only when it has no electrical, plumbing or mechanical work; anything larger requires a permit.¹ Unincorporated construction is governed by codes Iron County adopts as amended by Utah, and the statewide construction code applies to new construction and qualifying changes to existing buildings.¹⁷¹⁸

A structure used solely for agriculture and not for human occupancy can qualify for State Construction Code relief, but plumbing, electrical or mechanical permits may still be required.¹⁹ The exception has parcel-location and acreage conditions inside cities and county-approved subdivisions.¹⁹ Iron County issues a final certificate of occupancy only after required construction and grading work is complete and the listed compliance documents and applicable city signoff are in place.²⁰

Who issues Iron County building permits, and how do you reach them?

The Iron County Building Department issues county building permits and can be reached at 435-865-5350 or building.group@ironcountyut.gov at 82 N 100 E #102, Cedar City, Utah 84720.²¹ Inside Cedar City, the city issues building permits; Southwest Utah Public Health Department remains the septic authority.³⁵ Applications, online payment and inspection scheduling are available through the county's building permit portal.²¹²² An inspection request needs the permit holder's name, permit number and project address.²² Iron County inspects building, electrical, plumbing, mechanical and fuel-gas phases; if an inspector issues a correction notice, work cannot move to the next phase until the corrections pass reinspection.²³

Iron County publishes a fee schedule, but the permit FAQ does not state one flat project price.²⁴ Plan-review fees are nonrefundable, building-permit fees are not refunded after 180 days, and a project with no required inspection completed within 1 year must be renewed under the fee schedule.²⁴ Zoning questions go to the separate Iron County Planning Department at 435-865-5386.²⁵

Does Iron County have zoning?

Iron County administers zoning on unincorporated land; use the county Zoning Map with the assessor parcel number or property account number, then confirm the proposed use with Planning.²⁷²⁵ Cedar City and Parowan set their own zoning; Southwest Utah Public Health Department remains the septic authority throughout Iron County.⁴²⁶⁵ Unsewered residential subdivision lots generally need at least 5 acres unless they use a cluster or maximum-density option.⁹ In A-20 and RA-20, legally created or pre-August 14, 2000 lots below 20 acres have special rules; listed uses on lots below 15 acres require conditional-use treatment.²⁷

In unincorporated Iron County, chassis-retaining manufactured homes require HUD standards, a permanent foundation, at least 12 feet of width and more than 500 square feet; the table lists residential and agriculture zones and R4K.²⁸²⁹ Pre-1976 mobile-home placements are limited to existing Beryl mobile-home parks.³⁰ ADUs are permitted in A-20, RA-20, RR-20, R-5, R-2, R-1 and R-1/2, but prohibited in R4K, C, LI, I and IA.³¹³² ADUs also require owner occupancy, shared utilities, adequate septic capacity, parking and compliance with size and rental-duration limits.³³

How do septic permits work in Iron County?

Southwest Utah Public Health Department is the local authority for onsite wastewater permitting, plan review, inspections and records in Iron County.⁵ A permit and approved design are required before a septic system is installed, replaced or modified, and soil and percolation testing must be completed by a Utah-certified onsite professional before design or installation.⁸ Iron County applications also require Utah Division of Wildlife Resources documentation clearing the property for prairie-dog habitation.⁸

Every installed septic system must receive a final inspection before backfilling, scheduled through Environmental Health.³⁴ Only 17% of Iron County soils are rated without severe limitations for a conventional drain field, so treat septic feasibility as a pre-purchase question rather than assuming a standard gravity system will work.³⁵ Residential lots in subdivisions without public sewer generally must be at least 5 acres, unless they are part of a cluster or maximum-density subdivision.⁹ Utah requires wastewater to go to either a public sewer or a permitted onsite system; a septic system is a lawful off-grid sanitation route, not a permit-free one.³⁶³⁷

Can you live in an RV or tiny home on land in Iron County?

Iron County does not treat an RV or travel trailer as a year-round dwelling, and temporary RV use is permitted in some unincorporated zoning districts but prohibited in others.¹⁰¹¹ Temporary camping on a qualifying legal lot is limited to 1–16 days in a 30-day period, with sanitation, garbage, fire and waterbody setbacks.³⁸³⁹ Seasonal RV use for 17–180 days requires qualifying restricted seasonal access, a building permit, approved site plan, sewage arrangements, culinary water and solid-waste service.⁴⁰ The separate mobile-home rule limits living or sleeping outside established parks to temporary or seasonal periods unless the building official grants the specified utility, waste-service and winter-protection exception.¹²

In unincorporated Iron County, wheeled tiny homes and park models are listed only for travel-trailer parks, with a maximum area of 500 square feet.⁴¹⁴² Wheeled tiny homes may be at most 8 feet 6 inches wide; park models must be at least 8 feet wide and meet ANSI A-119.5-15.⁴¹⁴² Manufactured or modular tiny homes on permanent foundations are listed for R4K at 500 square feet or less, subject to district standards and building permits.¹³ Ask Iron County Planning to confirm the parcel's district and dwelling category before purchase.²⁵

Building a home in Iron County: the steps, in order

1. Confirm whether the parcel is unincorporated, look up its district on the Iron County Zoning Map using the assessor parcel number or property account number, then ask Planning to confirm the allowed dwelling type, setbacks and required land-use approvals.⁴³⁷²⁵
2. Verify legal water. A private well requires a valid water right and State Engineer permission before regulated construction, followed by work from the appropriately licensed well professional.¹⁵
3. Complete septic soil and percolation testing, obtain prairie-dog clearance documentation, and secure the health department's approved design and permit.⁸
4. Resolve access. The first public-road or county-right-of-way access for a new home is approved with the building permit; additional access needs an encroachment permit.¹⁶ A connection to a state highway requires UDOT's conditional access permit.⁴⁴
5. Submit the building-permit application and plans, then schedule required inspections through the portal; correct any cited problems and pass reinspection before moving to the next construction phase.¹²²²³
6. Arrange the septic final inspection before backfilling and complete all building closeout items before occupancy.³⁴²⁰

What should you check before buying land in Iron County?

Start with zoning, subdivision status, legal access, water rights and septic feasibility. Iron County Planning can identify the unincorporated zoning district, land-use rules and subdivision issues.⁴⁵⁶²⁵ In the A-20, RA-20 and RR-20 districts, qualifying road right-of-way can count toward the 20-acre minimum, but the credit is limited to 2 acres and carries location conditions.⁴⁶ An approved R-1/2 Performance Subdivision Option uses its own lot, setback, separation, height and coverage standards.⁴⁷ The Engineering Department handles county-road access, while UDOT controls state-highway connections.¹⁶⁴⁴

A domestic well requires a valid water right and State Engineer authorization.¹⁵ Only 17% of county soils avoid a severe conventional-drain-field limitation.³⁵ Manufactured homes in special flood-hazard areas must be elevated and anchored under the county's stated conditions.⁴⁸ The broader floodplain development permit requirement remains unconfirmed, so ask Engineering about mapped hazards and review before closing.

Iron County Greenbelt treatment assesses qualifying farmland by productive capability; eligibility generally requires at least 5 contiguous acres, agricultural use for the preceding 2 years and production requirements, with stated exceptions.⁴⁹ New applications are due May 1; development or non-use can trigger rollback tax for up to 5 preceding years.⁴⁹

Watch-outs

• Do not backfill an Iron County septic system until Southwest Utah Public Health Department completes the required final inspection.³⁴
• Iron County septic applications require prairie-dog-habitation development clearance documentation from the Utah Division of Wildlife Resources.⁸
• Owner-builder status does not erase building permits: the form must be submitted to the Building Department, and the exemption has ownership, use and construction-frequency conditions.¹⁴
• Iron County does not list an RV or travel trailer for year-round living; temporary and seasonal occupancy remain limited by zoning and county conditions.¹⁰¹¹¹²
• An unsewered residential subdivision lot generally must contain at least 5 acres unless it is part of a cluster or maximum-density subdivision.⁹
• We could not confirm a general minimum dwelling size or broader floodplain development permit requirement in Iron County; ask Planning about dwelling standards and Engineering about flood hazards before purchase.²⁵⁵⁰

Sources

1. ironcountyut.gov, quoted and re-checked
2. ironcountyut.gov, quoted and re-checked
3. Cedar City: Building & Zoning FAQs (Iron County), quoted and re-checked
4. Cedar City: Chapter 26, Article III — Zones (Iron County), quoted and re-checked
5. Septic Systems, quoted and re-checked
6. Planning, quoted and re-checked
7. ironcountyut.gov, quoted and re-checked
8. Septic Systems, quoted and re-checked
9. Sub Const Design Standards, quoted and re-checked
10. Chapter 17.16 - Establishment of Zoning Districts, quoted and re-checked
11. Chapter 17.16 - Establishment of Zoning Districts, quoted and re-checked
12. Iron County Code § 17.36.230, Location of mobile homes, travel trailers, recreational vehicles, boats, camping trailers, truck campers and motor homes, quoted and re-checked
13. Chapter 17.16 - Establishment of Zoning Districts, quoted and re-checked
14. Building Permit Packet and Owner/Builder Certification, quoted and re-checked
15. Water Well Drilling Information, quoted and re-checked
16. ironcountyut.gov, quoted and re-checked
17. Iron County Design Standards, quoted and re-checked
18. Utah Code § 15A-1-204, quoted and re-checked
19. Utah Code, Section 15A-1-204 - Adoption of State Construction Code; Exemptions, quoted and re-checked
20. Building Inspection Requirements, quoted and re-checked
21. Iron County Building Department (ironcountyut.gov)
22. ironcountyut.gov, quoted and re-checked
23. Building & Zoning, quoted and re-checked
24. ironcountyut.gov, quoted and re-checked
25. Iron County Planning Department (ironcountyut.gov)
26. Parowan: Parowan City Zoning Map (Iron County), quoted and re-checked
27. Iron County Code, § 17.16.040, Table of Site Development Standards, quoted and re-checked
28. Iron County Code, Section 17.16.035—Table of Residential Dwelling Type, quoted and re-checked
29. library.municode.com, quoted and re-checked
30. Iron County Code, Section 17.16.035—Table of Residential Dwelling Type, quoted and re-checked
31. Iron County Code, Chapter 17.16—Establishment of Zoning Districts, quoted and re-checked
32. Chapter 17.16 - Establishment of Zoning Districts, quoted and re-checked
33. Iron County Code § 17.36.400, Accessory dwelling units (ADUs), quoted and re-checked
34. Septic Systems, quoted and re-checked
35. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
36. Septic Systems, quoted and re-checked
37. Septic Systems, quoted and re-checked
38. Iron County Commission Meeting Minutes, February 8, 2021, quoted and re-checked
39. Iron County Commission Meeting Minutes, February 8, 2021, quoted and re-checked
40. Iron County Commission Meeting Minutes, Ordinance 2021-1 seasonal-use provisions, quoted and re-checked
41. Iron County Code, Section 17.16.035—Table of Residential Dwelling Type, quoted and re-checked
42. Iron County Code, Section 17.16.035—Table of Residential Dwelling Type, quoted and re-checked
43. Business License, quoted and re-checked
44. Conditional Access Permit (Utah statewide rule), quoted and re-checked
45. Planning, quoted and re-checked
46. Iron County Code, § 17.16.040, Table of Site Development Standards, quoted and re-checked
47. Iron County Code, § 17.16.040, Table of Site Development Standards, quoted and re-checked
48. Iron County Code § 15.12.160, Flood hazard reduction—General standards, quoted and re-checked
49. Iron County Greenbelt Act, quoted and re-checked
50. Iron County Engineering Department (ironcountyut.gov)

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.