Colorado’s mountains, open spaces, and rural getaways are tailor-made for self-reliant living. Whether you’re building a cabin, setting up a tiny house, or planning a sustainable homestead, composting toilets are often at the top of the “wish list.” But can you actually use a composting toilet legally in Colorado? And what does the law require? Here’s the real scoop—so you can plan your project without nasty surprises from the building inspector.
Are Composting Toilets Legal in Colorado?
Yes, composting toilets are legal in Colorado. The state recognizes them as an alternative to traditional flush toilets and septic systems—especially in places where conventional septic just isn’t practical. But you can’t just install anything you want. Colorado’s laws and rules for composting toilets are clear, and you’ll need to check with your local county for the final word.
Who Sets the Rules?
Composting toilet rules in Colorado are set by the Colorado Department of Public Health & Environment (CDPHE) at the state level, but local county health departments and building officials enforce them and often add their own requirements. Each county can adopt slightly different policies—so what’s allowed in Park County might be off-limits in Boulder or Larimer counties.
What Does Colorado Law Say?
- Composting toilets are allowed statewide, but they must be approved models. Colorado usually requires systems certified to NSF/ANSI Standard 41—the national safety and performance benchmark.
- Permits are almost always required. You’ll need to submit a waste management plan, showing how you’ll handle both toilet waste (compost) and greywater (wastewater from sinks, showers, etc.). Inspections are often part of the process.
- Composting toilets alone are rarely enough. Even if you use a composting toilet, Colorado law nearly always requires a legal solution for greywater. This could mean a small septic/leach field, an engineered greywater system, or holding tank.
- Proper installation and maintenance are key. Toilets must be set up and maintained so they don’t create nuisance conditions—odors, pests, or leaks. Health departments can order removal or require upgrades if the system fails.
Where Are Composting Toilets Most Likely Approved?
Composting toilets get approved most easily in:
- Remote or off-grid locations without water or sewer access
- Tiny houses, cabins, and seasonal recreational properties
- Properties where septic is not practical due to rocky soil, high water table, or small lot size
In urban or suburban areas, rules are stricter and composting toilets may be denied unless you have a strong case (such as retrofitting a historic property or special environmental needs).
Steps to Legal Installation
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Contact your county building and health department:
- Ask about their composting toilet rules and application process. Local officials have the final say and may have extra forms or requirements.
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Choose a certified, approved composting toilet:
- Most counties want NSF/ANSI Standard 41 certified toilets. Save your paperwork for permits and future resale.
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Submit a waste management plan:
- This plan should explain how you’ll handle both compost and greywater. Many counties require a soil test (“perc test”) to see if a small leach field is possible.
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Get a permit and inspection:
- Install the toilet according to manufacturer and code rules. An inspector may visit to verify everything is set up safely and legally.
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Maintain your system:
- Follow manufacturer guidelines for maintenance and compost handling. Nuisance complaints (like odor or flies) can lead to enforcement actions.
Greywater and Liquid Waste Rules
Composting toilets only handle human solid waste and sometimes urine, depending on the design. Colorado law requires that all greywater be treated and disposed of safely—usually in a permitted septic system, greywater field, or approved irrigation setup. Discharging greywater onto the ground, into streams, or in an unsafe manner is illegal.
Common Pitfalls (and How to Avoid Them)
- Don’t ignore the greywater system—your permit depends on it.
- DIY or homemade composting toilets are rarely approved unless you can prove they meet NSF/ANSI 41 standards.
- Permitting can take time—plan ahead and budget for professional help if needed.
- If you’re building in a remote area, keep records for resale or future inspections.
Penalties for Non-Compliance
Installing a composting toilet without permits, ignoring greywater requirements, or creating a nuisance can lead to fines, removal orders, or trouble when selling your property. County health inspectors can issue stop-work orders or require you to install a traditional system if your setup isn’t safe or legal.
Helpful Resources
- Colorado Department of Public Health & Environment – Septic, composting, and alternative systems info
- NSF/ANSI 41 Composting Toilet Standard – Certified products and details
- EPA: Composting Toilets – Federal overview and best practices
Final Thoughts: Composting Toilets in Colorado—Yes, But Plan Carefully
Colorado is friendly to composting toilets, especially in rural and off-grid settings, but you need to follow the rules—permits, approved toilets, and safe greywater disposal are key. Work with your county early in your planning, keep everything above board, and you’ll be set for clean, green living in the Rockies!
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