Building permits, zoning and land rules in Natrona County, Wyoming

Yes. Unincorporated Natrona County requires permits for new residential and commercial buildings, additions, renovations, and electrical, plumbing and mechanical work¹. Construction may begin only after the permit is approved and issued; emergency equipment replacement or repair paperwork may be submitted the next business day¹. Building submissions require an application, site plan, building plans and the correct fees, and some plans may require a Wyoming-licensed professional engineer⁹. The county enforces adopted building-code requirements, and permitted work requires inspections, including a final inspection to close the permit^1,10,11. These rules cover unincorporated land; for a parcel inside a city, ask that city's building and planning offices, because the county's page does not establish that its building permits apply there¹⁰. Septic permits and well permits are separate and are not part of the building permit^5,7. An owner may do work on the owner's primary residence, but the correct permits, code compliance and all necessary inspections still apply¹.

The Natrona County Building Department handles plan review, building-permit issuance and inspections at 200 N. Center ST, Room 205, Casper, WY 82601; call 307-235-9435 or use the online permit portal linked above¹⁰. The Natrona County Planning Department handles zoning, related planning permits, subdivision regulations and code enforcement at 200 N. Center St., Room 202, Casper, WY 82601; call 307-235-9447¹². Planning applications may require zoning, floodplain, subdivision or other approvals⁹. The Planning Department implements the county's subdivision regulations and processes subdivision applications and exemption forms¹². The Casper-Natrona County Health Department is the separate contact for septic permits (small wastewater systems) at 307-235-9340, and it holds that role for Natrona County whichever building or planning office covers the parcel^4,13.

Yes. Natrona County's zoning resolution applies to all land in the county's unincorporated portions, where uses may be permitted, conditional or prohibited by district^2,6. Minimum lot size varies with the zoning district and with public or private sewer and water service; published standards range from 4,000 square feet to 35 acres³. Setbacks vary by district, road type, building type and adjacency; examples include 25 feet from a public road and 10 feet from front, side and rear property lines³. Some residential districts permit one primary dwelling and one accessory dwelling unit per lot, subject to district and use rules¹⁴. Ask the Planning Department to identify the parcel's district before siting either dwelling¹².

The Casper-Natrona County Health Department administers small wastewater systems throughout Natrona County under delegated Wyoming DEQ authority⁴. The Health Department requires a septic permit before construction, installation or modification of an onsite system across the county, although its regulations allow stated exceptions and written determinations that a permit is unnecessary^4,5. For permitted installation, notify the department at least 24 hours before covering the system; inspection occurs before earth covers the system or it is used⁵. If a representative cannot perform the final inspection after notice, photographic evidence is due within five working days⁵. Only 30.9% of Natrona County soils lack severe limits for a conventional drain field, so establish site suitability before budgeting for a standard system⁸.

Unincorporated Natrona County treats overnight RV accommodation as temporary use for less than 90 days and requires a Zoning Certificate plus temporary water, sewer and utilities². Agricultural property larger than 10 acres may have no more than four temporary RVs, while residential property may have no more than one². During construction of a permanent structure, an RV or motor home may be permitted as a temporary dwelling for up to one year with a Zoning Certificate and temporary water, septic or sewer service, and utilities². Extensions track the building-permit period, and the RV cannot remain more than 30 days after substantial completion or the permanent dwelling's Certificate of Occupancy². We could not confirm a specific tiny-home occupancy rule or a minimum dwelling size; ask Planning about the proposed structure and district¹².

1. Ask the Planning Department to identify the zoning district, allowed residential use, minimum lot size, setbacks and any subdivision or other planning review^3,6,12.

1. If creating a new approach onto a county-maintained road, obtain a Driveway Access Permit from County Road & Bridge¹⁵.

1. Apply to the Casper-Natrona County Health Department for the required onsite-wastewater approval, unless the department determines in writing that an exception applies⁴.

1. If the parcel needs a well, obtain an approved Wyoming State Engineer permit before drilling⁷.

1. Submit the building permit application, site plan, building plans and correct fees to the Building Department; some plans may require a Wyoming-licensed professional engineer^9,10.

1. Arrange county building inspections and the septic inspection before the system is covered or used^1,5.

1. For projects requiring a Certificate of Occupancy, request it 7 business days in advance¹¹.

Confirm the zoning district, permitted use and parcel-specific setbacks with the Planning Department before relying on a listing description^3,12. A new access or approach onto a county-maintained road requires a Driveway Access Permit from County Road & Bridge, and receiving an address does not make the county responsible for access or road maintenance¹⁵. Verify legal access carefully: Wyoming's large-parcel provision generally covers parcels of 35 acres or more and requires binding, recordable ingress, egress and utility easements at least 40 feet wide to a public road unless properly waived¹⁶. Federal land covers 44.6% of Natrona County, making boundary and access checks especially relevant⁸. Only 30.9% of county soils lack severe limits for a conventional drain field, so price septic feasibility before closing⁸.