Clean water: On-site wastewater treatment systems

How does this affect you?

• For on-site wastewater treatment systems with flows 2,000 gallons per day or less, permitting is conducted by local counties.
  • Each local public health agency in Colorado has adopted regulations that are at least as stringent as Regulation 43. For copies of these regulations, contact your local county or public health agency.
• We must provide initial review and acceptance of products and technology.
• On-site wastewater treatment systems with flows greater than 2,000 gallons per day must follow the design review facility approval process.

Local agency OWTS program information

• Colorado County OWTS permit data, 2021.
• Colorado County OWTS permit data, 2022.
• Colorado County OWTS permit data, 2023.
• Map of local agencies that implement a Transfer of Title inspection program.
• Map of local agencies that utilize the part A installer exam.
• Local agency OWTS program decisions, “opt-in” chart.

Regulation 43:product acceptance lists

• Septic tank acceptance summary list.
  • Acceptance letters.
• Higher-level treatment systems acceptance summary list.
  • Acceptance letters.
• Distribution products.
  • ​Acceptance letters.

Product review submittal forms

• Septic tank products.
  • Annual septic tank watertightness test reporting.
• Higher level treatment products.
• Distribution products.

Forms for local public health agencies

• Regulation review submittal for regulation revisions.
• On-site wastewater treatment system permit surcharge submittal.

Regulation 43 policies and clarifications

• CW9 Soil Type R Long Term Acceptance Rate Policy.
• Design using chambers.
• ​Infiltrative surface.
• Composting toilets.
• Variance requirements from OWTS to a Well.
• Variance requirements from OWTS to a Cistern.
• Vertical Isolation and Media Depth Chart.

Additional documents

• On-site Wastewater Treatment System Act.
• Mound system guidance document.
• Mound system spreadsheet.
• Sodic soil guidance.
• Time Dosing Guidance.
• Wastewater site application Policy 6.
• Non-pressurized drip dispersal system design document.
• OWTS design plan review checklist.
• Evaluating sand gradations.
• Sand gradation graph.
• PVC pipe informational document.
• Discharges from marijuana facilities information.
• Power outage - OWTS guidance.
• Post-wildfire - OWTS guidance.

Related OWTS links

• EPA, Septic System Frequently Asked Questions.
• EPA Onsite/decentralized systems.
• USDA Natural Resources Conservation Services (NRCS) Soils.
• National Association of Wastewater Technicians (NAWT).
• National On-site Wastewater Recycling Association (NOWRA).
• Colorado Professionals in On-site Wastewater (CPOW).

Contact us

• Systems less than or equal to 2,000 gallons per day
  • Chuck Cousino | chuck.cousino@state.co.us
• Systems greater than 2,000 gallons per day
  • David Kurz | david.kurz@state.co.us