Is Composting Toilets Legal in Colorado? (2026)
Yes — Composting Toilets are legal in Colorado as of 2026.
Quick Answer
Composting toilets are explicitly permitted in Colorado under state plumbing or health codes. No significant legislative changes since the Water Quality Control Commission updated Regulation 43.
What the Law Says
Permits the use of composting toilets as primary or supplemental toilet systems in Colorado, requiring compliance with state plumbing and health codes, including NSF 41 certification, and mandates separate on-site wastewater treatment systems for greywater.
— 5 CCR 1002-43
| Category | Details |
|---|---|
| State Plumbing Code | Legal; NSF 41 certified units typically required |
| Permit Requirements | Legal to sell and install |
| Code Violation Penalties | Must meet state health department requirements. |
| Pending Legislation | None known |
No significant legislative changes since the Water Quality Control Commission updated Regulation 43. Local ordinances may change, so checking with the county is crucial.
Enforcement Reality
Enforcement is handled by local county health agencies, which permit on-site wastewater treatment systems (OWTS). A composting toilet may be used, but an OWTS is still required for greywater.
A common mistake is believing a composting toilet can completely replace a septic system. In Colorado, it can only be used for toilet waste, and a separate system is needed for all other wastewater.
Local Exceptions
None identified. State law applies uniformly across Colorado. Local ordinances may still vary — check with your city or county government for any additional rules.
Bottom Line
Composting Toilets are legal in Colorado. You can installing a composting toilet without violating state law, though federal rules and local ordinances may still apply. Always verify current law before acting.
Colorado vs. the Rest of the US
Across the US, installing a composting toilet is fully legal in 20 states, restricted in 30, and illegal in 0. Colorado falls in the LEGAL category.
View the full 50-state map →Neighboring States
Laws change at state lines. Here is how bordering states compare on Composting Toilets:
Frequently Asked Questions
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Reviewed by cross-referencing the cited state statute against current legislative databases and regulatory publications.
Sources & Verification
This page was reviewed by Ethan Harper by comparing the legal status against the cited state statute. AllowedHere is an informational resource and does not provide legal advice. Consult a licensed attorney for guidance specific to your situation.
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