On-site wastewater treatment systems (OWTS), also known as septic systems, are governed by Regulation 43.
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.
- Higher-level treatment systems acceptance summary list.
- Distribution products.
Product review submittal forms
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
- 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
Contact us
Systems less than or equal to 2,000 gallons per day
Chuck Cousino
Systems greater than 2,000 gallons per day
David Kurz