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§ 02
When a permit is required
Permit triggers and exempt work for Crook County
Crook County has NOT adopted a county-wide building code for private residential construction. No general building permit for residential construction in unincorporated areas is apparent from publicly available sources. Septic permit required whenever a new on-site wastewater system is installed.
No building code / no permit required for residential construction in unincorporated areas
One-Split Subdivision: Properties may be split once without going through the full subdivision review process, subject to the county's one-split regulation
Subdivision Exemptions: Crook County maintains subdivision exemption criteria. Contact the Planning Department for the current exemption list.
Agricultural exemptions: Agricultural land uses and accessory farm structures are generally outside the scope of any local code in Crook County given the absence of a building code
- Exempt No building code / no permit required for residential construction in unincorporated areas
- Exempt One-Split Subdivision: Properties may be split once without going through the full subdivision review process, subject to the county's one-split regulation
- Exempt Subdivision Exemptions: Crook County maintains subdivision exemption criteria. Contact the Planning Department for the current exemption list.
- Exempt Agricultural exemptions: Agricultural land uses and accessory farm structures are generally outside the scope of any local code in Crook County given the absence of a building code
Note: The absence of a county building permit program is confirmed by multiple independent sources. However, county policies can change; always verify current requirements with the Planning Department at (307) 283-4548 before breaking ground.
Required documents
- Site plan
- Soil evaluation
- System design by a licensed Wyoming engineer or sanitarian (where applicable)
- Building code
- None formally adopted for private residential construction in unincorporated areas. The county recommends following the Wyoming Building Code (2021 IBC base) and related I-Codes voluntarily for structural and life-safety purposes.
- Owner-builder
- No county restriction identified; owner-builder construction is permissible in the unincorporated county.
- Contractor requirements
- No county-level contractor license requirement. Wyoming does not have a statewide general contractor license. Electrical work requires a licensed electrician under Wyoming State Fire Marshal rules.
§ 03
Application process
Application → plan check → issuance → inspection → final
- 01 Download the Crook County Conventional Small Wastewater Application Packet from the county website or obtain from the Growth and Development Department
- 02 Complete the application and include all required documentation (site plan, soil evaluation, system design by a licensed Wyoming engineer or sanitarian where applicable)
- 03 Submit completed application to the Growth and Development Department with the $200.00 permit fee
- 04 Crook County Planning Administrator reviews for compliance with the Crook County Small Wastewater Regulation
- 05 Permit to Construct issued
- 06 Construct the system
- 07 Contact Caleb Peters to schedule the required inspection prior to backfilling or covering the system
- 08 Inspection passed; system may be covered
§ 04
Required inspections
Scheduling and sequence
How to schedule
- Contact Caleb Peters at calebp@crookcounty.wy.gov or (307) 283-4548 to schedule septic inspections (email)
- Scheduling deadline
- Prior to backfilling or covering the septic system
Typical sequence: Septic inspection required prior to backfilling or covering the system. Electrical inspections performed by the Wyoming State Fire Marshal's Office/Electrical Safety Division for work requiring a state electrical wiring permit.
§ 05
Frequently asked
Common questions about unincorporated Crook County permits
01 Do I need a building permit in unincorporated Crook County, WY? ▸
Crook County has NOT adopted a county-wide building code for private residential construction. No general building permit for residential construction in unincorporated areas is apparent from publicly available sources. Septic permit required whenever a new on-site wastewater system is installed.
02 How do I apply for a building permit in unincorporated Crook County, WY? ▸
To apply for a building permit in unincorporated Crook County, WY, follow these steps: 1. Download the Crook County Conventional Small Wastewater Application Packet from the county website or obtain from the Growth and Development Department 2. Complete the application and include all required documentation (site plan, soil evaluation, system design by a licensed Wyoming engineer or sanitarian where applicable) 3. Submit completed application to the Growth and Development Department with the $200.00 permit fee 4. Crook County Planning Administrator reviews for compliance with the Crook County Small Wastewater Regulation 5. Permit to Construct issued 6. Construct the system 7. Contact Caleb Peters to schedule the required inspection prior to backfilling or covering the system 8. Inspection passed; system may be covered
03 What work is exempt from building permits in unincorporated Crook County, WY? ▸
Not all construction work requires a permit in unincorporated Crook County, WY. The following work is generally exempt: No building code / no permit required for residential construction in unincorporated areas; One-Split Subdivision: Properties may be split once without going through the full subdivision review process, subject to the county's one-split regulation; Subdivision Exemptions: Crook County maintains subdivision exemption criteria. Contact the Planning Department for the current exemption list.; Agricultural exemptions: Agricultural land uses and accessory farm structures are generally outside the scope of any local code in Crook County given the absence of a building code. Note: The absence of a county building permit program is confirmed by multiple independent sources. However, county policies can change; always verify current requirements with the Planning Department at (307) 283-4548 before breaking ground. When in doubt, confirm with the local building department before starting work.
04 How do I schedule a building inspection in unincorporated Crook County, WY? ▸
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in unincorporated Crook County, WY via: Contact Caleb Peters at calebp@crookcounty.wy.gov or (307) 283-4548 to schedule septic inspections. Prior to backfilling or covering the septic system.
last verified April 2026
source Crook County Growth and Development Department ↗
entry id permits/wyoming/crook/unincorporated
Educational reference. Permit rules and fees change — confirm current requirements directly with Crook County Growth and Development Department before applying. Jaspector is not legal advice.