Building permits, zoning and septic rules in Johnson County, Wyoming

Johnson County does not issue a county residential building permit for an ordinary home in its unincorporated area¹. Wyoming nevertheless requires plan approval and a Permit to Construct before work begins on specified projects in state fire-marshal jurisdiction². The state fire marshal inspects covered new construction and remodeling after completion¹⁰. A covered new building cannot be occupied until the state fire marshal issues a certificate of occupancy; a covered remodel receives a letter of compliance¹⁰. Buffalo is different because the city has adopted a residential code for buildings and structures inside its incorporated area¹¹. Ask the Johnson County Planning Department whether subdivision or floodplain review applies even when no county residential building permit is issued⁴.

Johnson County has no residential building department to call because the county does not issue residential building permits in unincorporated areas¹. The Johnson County Planning Department handles septic permits, subdivision review, floodplain development and rural addressing⁴. Reach the Planning Department at 307-684-1907 or visit 26 N Desmet Avenue, Suite A, Buffalo, WY 82834⁴. Septic and subdivision applicants should ask the department for current dollar amounts: Johnson County adopted fees for both through Resolution #673, but the county's published notice does not list the amounts¹². A groundwater well uses a separate state permitting process rather than a Johnson County permit⁷.

Johnson County has no county-level zoning regulations for its unincorporated land¹. County zoning therefore sets no minimum dwelling size, minimum lot size, setbacks, lot-coverage limit or building-height limit¹. That answer changes inside municipal boundaries: Buffalo applies its own zoning within city limits, while Kaycee's current zoning status could not be confirmed³. Johnson County separately reviews subdivisions, lot divisions and other land-development plans in unincorporated areas under regulations adopted by the county⁸. Ask the Planning Department how those subdivision regulations apply to a particular parcel because the available county page does not publish the detailed local standards or exemptions^4,8.

Every new small wastewater treatment facility, privy, outhouse, holding tank, septic replacement or septic modification in Johnson County needs a Planning Department permit under authority delegated by the Wyoming Department of Environmental Quality⁴. A registered, licensed engineer must design every system, and the department returns incomplete applications⁴. Each application must include the applicable Resolution #673 fee; ask the Planning Department for the current amount because the county's notice publishes the fee authority but not dollar figures¹². Only 17% of Johnson County land has soils without severe limitations for a conventional drain field, so obtain a site evaluation before choosing a homesite¹³. Contact the county before designing a non-conventional system because some subdivisions require that treatment type⁴. Arrange the county inspection at least 24 hours before backfilling; a certificate of completion is required only when the inspection was not completed⁴.

Unincorporated Johnson County places no county zoning restriction on RV occupancy, temporary camping, tiny-home occupancy, manufactured-home occupancy or accessory dwellings because the county has no zoning ordinance¹. Septic rules still apply: any privy, outhouse, holding tank or other small wastewater system requires county approval, including replacements and modifications⁴. Subdivision rules can also affect the parcel even without zoning⁸. Inside Buffalo, city zoning applies instead; Kaycee's current zoning status could not be confirmed³.

1. Confirm whether the parcel is outside Buffalo and ask the Planning Department whether floodplain or subdivision review affects the site^3,4.
2. If land is being divided, ask the Planning Department what Johnson County's subdivision regulations require before recording or construction^4,8.
3. Determine whether the project falls within Wyoming fire-marshal plan-review jurisdiction; if it does, obtain the state Permit to Construct before work begins².
4. Obtain a soil evaluation and hire a registered, licensed engineer to design the septic system⁴.
5. Submit a complete septic application with the current Resolution #673 fee to the Planning Department^4,12.
6. Apply to the Wyoming State Engineer before drilling a well, and use a Wyoming-licensed driller⁷.
7. Arrange the septic inspection at least 24 hours before backfilling⁴.
8. For a project in state fire-marshal jurisdiction, obtain the state certificate of occupancy or letter of compliance before use¹⁰.

Water is the headline concern: Johnson County averages just 15.2 inches of precipitation a year, with severe drought in 20.2% of years, so a reliable well and water rights matter as much as anything else you'll evaluate¹³. Soils compound that: only 17% of the county's land is free of severe limitations for a conventional septic drain field, so plan on a site evaluation and an engineered system on most parcels¹³. Terrain is mixed, with about 49% of the county at 15% slope or less, and 31.2% of the county is federal land, worth checking against any parcel boundary before you buy¹³. If the parcel was divided or will be divided, ask the Planning Department to confirm compliance with Johnson County's subdivision regulations^4,8. Typical carrying costs include an effective property tax rate near 0.6% and a median annual bill around $1,634¹³.