Septic / Small Wastewater System Permit in Unincorporated Sheridan County, Wyoming
VerifiedRequired countywide for installation of a new conventional septic tank and leachfield system (or other small wastewater disposal system) in unincorporated Sheridan County, under the county's Rules and Regulations Governing Wastewater Systems (aligned with WY DEQ Water Quality Rules and Regulations Chapter 25).
Verified 2026-07-01 · Source
When you need this permit
- Covers conventional systems only: wastewater flow under 2,000 gallons/day of domestic sewage, standard trench/bed disposal (stone-and-pipe or chambers), seasonal high groundwater/bedrock/impervious clay 4+ feet below the proposed leachfield bottom, and soil percolation rate between 5 and 60 minutes per inch
- Non-conventional systems (outside those parameters) require direct consultation with Sheridan County Public Works; systems over 2,000 gal/day or non-domestic waste route to the WY DEQ Underground Injection Control (UIC) Program
- Groundwater test pit dug 4 feet deeper than the bottom of the proposed leachfield, open at least 24 hours, and inspected by a Sheridan County representative prior to submission
- Percolation test performed per county instructions
- Proof of ownership (recorded deed) required; notarized authorization needed if applicant is not the owner
- 24-hour notice required to schedule the final inspection prior to backfilling the system
- Fee due upon submission; starting installation before approval is subject to a fine
Required documents
- Req
Septic System Permit Application (Sheridan County / WY DEQ design forms, Water Quality Division)
22-page combined application, site suitability, percolation test, and leachfield design worksheet package
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Septic permit fee (due upon submission) | $250.00 | Sheridan County Septic System Permit Application |
Review timeline
~5–20 business days
Typical estimate — confirm current times with the Unincorporated Sheridan County building department
Inspection process
- 1
Groundwater Test Pit Inspection
Pit dug 4 feet deeper than the bottom of the proposed leachfield, open 24+ hours, inspected by a county representative prior to application submission
- 2
Final / Backfill Inspection
24-hour notice required; must pass before the system is backfilled
Tips
- Sheridan County Conservation District offers up to 50% cost-share assistance for replacing pre-1973 septic systems serving a single-family dwelling that impact certain listed impaired waterbodies — ask Public Works or SCCD (307-672-5820) if your replacement may qualify.
- For systems exceeding 2,000 gallons/day or non-domestic wastewater, contact the WY DEQ Underground Injection Control Program (307-777-5623) instead of the standard county application.
Frequently asked questions
- Who issues septic permits in unincorporated Sheridan County?
- Sheridan County Public Works issues septic/small wastewater permits countywide, following design standards aligned with Wyoming DEQ Water Quality Rules and Regulations Chapter 25. The fee is $250, due at submission.
Sources & verification
Verified against official sources. Last reviewed 2026-07-01.
- Sheridan County Public Works Department (Planning / Building Official) — official building department
- Sheridan County Septic System Permit Application
Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Unincorporated Sheridan County building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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