On-Site Wastewater Treatment (Septic) Systems

San Miguel County's population has more than doubled since 1990, placing a growing demand on the county's infrastructures. Although public sewage treatment facilities serve the majority of San Miguel County (SMC) residents, many others rely on onsite wastewater treatment systems (OWTS or septic systems). Such systems, if constructed and maintained properly, provide a reliable and efficient means of wastewater treatment and disposal.

Under Public Health’s Environmental Health Department, the OWTS program administers the development, permitting, installation, repair and replacement of domestic wastewater treatment systems with a daily flow of less than 2000 gpd (gallons per day) in San Miguel County.

  1. OWTS Process
  2. OWTS Fees
  3. Record Requests
  4. Additional Resources

To begin construction of an OWTS, both a development permit from the SMC Planning Department and an OWTS permit (PDF) from the SMC Public Health Department are required (see below for exemptions).  

Additional requirements include:

  1. A soil evaluation by a Colorado Professionals in Onsite Wastewater (CPOW) certified competent soil technician
  2. A set of OWTS plans stamped by a Colorado Professional Engineer (CPE)
  3. Independent review and conditional approval of proposed OWTS plans by a San Miguel County contracted Colorado Professional Engineer (CPE)
  4. Final SMC Environmental Health review

Click here for the 2023 SMC OWTS Permit Application (PDF) and additional details.


In all areas in San Miguel County EXCEPT the West End Zone and Ophir a development permit from the SMC Planning Department is required prior to construction of an OWTS. Permitting efforts can be pursued concurrently.