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

For ordinary construction below the county threshold, unincorporated Platte County has no adopted building-code requirements and does not require the high-value Construction Certificate^1,2. A Construction Certificate is required when the total project value is $1,000,000 or higher; its published fee is 0.5% of only the amount above $1,000,000, subject to a $200 minimum, and Road and Bridge approval is also required; the county may also require a road use agreement to address infrastructure impacts^2,6. Incorporated towns can have their own building codes and permits, so the county answer does not control a site inside town limits, while Wyoming DEQ septic permits and State Engineer well permits apply county-wide^1,3,7. County zoning, septic, well, driveway and floodplain requirements remain separate from building-code review^2,3,7,8. Platte County has not confirmed a separate county building-inspection program or certificate-of-occupancy requirement; ask Planning and Zoning about the specific parcel and project⁴.

Platte County Planning and Zoning administers the county land-use regulations, assigns rural addresses and supports the Planning and Zoning Commission^4,9. Reach the office at (307)322-1330 or planner@plattecountywyoming.com, or visit 800 9th Street, PO Box 728, Wheatland, WY 82201⁴. Ask that office to confirm the zoning district, allowed use, site-plan needs and whether a Construction Certificate applies⁴. A site plan must show the driveway location; county-road encroachments go through Platte County Road and Bridge, while state-highway encroachments go through WYDOT Right-of-Way⁸. Road and Bridge can be reached at 307-322-3113 or mbolin@plattecountywyoming.com at 23 Main Drive, Wheatland, WY 82201¹⁰. Platte County has not confirmed a general county building inspection or occupancy-certificate process, so ask Planning and Zoning to identify any project-specific review before work starts⁴.

Yes. Platte County regulates land use in the unincorporated county, and any unincorporated area not otherwise zoned is designated Ranching, Agriculture and Mining, or RAM². Residential districts have specific lot and setback standards. Where public water and wastewater serve the lot, the minimum lot area in the Class I and Class II residential districts is 7,000 square feet; with one individual water or wastewater system it is one-half acre, and where both are individual it is 1 acre, still subject to soil capability². Class I setbacks are 25 feet from the public right-of-way at the front, 10 feet at the side and 6 feet at the rear². RAM structures must be at least 30 feet from public roadway easements or rights-of-way and 25 feet from property lines, and the county repealed the RAM minimum lot area in 2023². Class II buildings are generally limited to 40 feet, with a special permit required above that height and fire-fighting capability still controlling². Confirm the parcel's mapped district with Planning and Zoning before relying on any dimensional standard⁴.

Wyoming DEQ, not Platte County, is the permitting authority for small wastewater facilities in Platte County³. The general permit covers installation, repair or replacement of individual or commercial sewage-disposal systems treating less than 2,000 gallons of domestic sewage per day³. Construction cannot begin until the permitting authority issues authorization, and a Certificate of Completion is due when installation is complete³. Only 48.3% of Platte County soils are rated without severe limitations for a conventional septic drain field, so make septic feasibility an early parcel-level question rather than assuming a standard leach field will work¹¹. The reviewed rules do not confirm a distinct inspection requirement or a general alternative for off-grid sanitation. Ask DEQ what site evaluation, design, completion documentation and inspection apply to the proposed system³.

Platte County regulates travel-trailer parks, including developments for seasonal recreation-oriented campers and recreational vehicles; park plans require Wyoming DEQ review and approval². That park rule does not answer whether someone may live in an RV on an ordinary private parcel, and Platte County has not confirmed a general rule for that use. Platte County also has not confirmed a distinct tiny-home category or a countywide minimum dwelling-floor-area requirement. Class I residential rules allow one mobile home per lot, while mobile-home subdivisions require a Special Use Permit and compliance with the county subdivision regulations². In the RAM district, an accessory dwelling is allowed only when accessory to a preexisting commercial, industrial or general agricultural operation². Ask Planning and Zoning how the proposed unit is classified and what approvals apply⁴. Any septic system still needs DEQ authorization before construction³.

1. Ask Platte County Planning and Zoning to confirm the parcel's district, allowed residential use, lot-area standard, setbacks and site-plan requirements^2,4.

1. Determine whether the project reaches the $1,000,000 Construction Certificate threshold; if it does, obtain the certificate and Road and Bridge approval before proceeding².

1. Apply to Wyoming DEQ for septic authorization and do not start septic construction until authorization is issued³.

1. Submit the groundwater application to the State Engineer and receive an approved well permit before drilling; the domestic filing fee is $50⁵.

1. Put the driveway location on the site plan, then apply to Road and Bridge for a county-road encroachment or to WYDOT for state-highway access^8,10.

1. If the site is in a special flood-hazard area, ask Planning and Zoning which review and permit apply; county rules subject such development to the county floodplain resolution and federal standards, while the fee schedule lists a Floodplain Development Permit^2,4.

Start with legal access, zoning and wastewater feasibility. Wyoming's large-parcel rule generally requires parcels of 35 acres or more to have binding, recordable ingress, egress and utility easements at least 40 feet wide to a public road unless the buyer specifically waives that protection in a binding, recordable document¹². Platte County receives about 14.4 inches of precipitation annually and has experienced severe drought in about 21.5% of years, so verify water rights, well-permit prospects and expected yield before treating a well as assured¹¹. About 48.3% of county soils avoid a severe conventional-drain-field limitation, making soils and DEQ septic review material to the budget¹¹. The effective property-tax rate is about 0.6%, and the median annual property-tax bill is about $1,464¹¹. Check the flood map and whether access joins a county road or state highway; special flood-hazard development and the two road systems follow different approval paths^2,8.