Are Composting Toilets Legal?


This is a complex question, unfortunately. If you are building a new home, the building inspector might want you to install an “approved” composting toilet system. What this means varies widely from place to place. In some areas, composting toilets are welcome, if properly installed and operated. In other areas, authorities don’t seem to be interested in approving them. In my region, the inspector has told me “I understand what you are doing, and I like it. But there is nothing in the code book about it, so don’t ask and I won’t say no”. If you need a permit, it’s best to talk to your local authorities. You might have to speak with someone in sanitation, engineering, a department manager, or someone else in charge, as a special permit may be required. The regular building inspector is more likely to just say no. If you have forward thinking people at your local government offices, you should be able to show them your waste management plan. If it is a sound plan, you may well get approval.In urban areas especially, where new houses are concerned, they might require that basic plumbing infrastructure be built into the house ( drain pipe, vent stack and water supply). This is so future owners of the home will be able to choose the type of toilet they use, and not be locked in to using a composting toilet.In a way I can understand the concern. The municipality or county is handing over the very serious responsibility of dealing with human waste over to the home owner. They are concerned that a careless person might not deal with the output of their composting toilet appropriately, and someone could get sick, or water could be contaminated. When used properly, composting toilets produce harmless fertilizer only, but it does require care and attention.CertificationsSome toilets have certifications from independent testing agencies. This might be an ETL certification ( for urine diverting toilets) or an NSF 41 certification (non-urine diverting toilets). Complicating matters is that local inspectors have no knowledge of the important distinction between urine diverting and non-urine diverting toilets, and may request the incorrect certification. In some areas “certification” is required. In many places, it is not. In addition, there are many other certifying agencies. Muddy waters indeed.

Certifications are problematic. First, they do not address what happens to the solid material once it’s removed from the toilet – and that is the most important thing! Any composting toilet could possibly have fecal pathogens in the solid waste that you remove. It is critical that this waste be carefully handled according to instructions, and that fecal contamination does not occur. The certifications provide absolutely no assurance of that.

Secondly, some certifications are very expensive to obtain. They can cost over $40,000, with annual ongoing fees of several thousand dollars per product or model. For this reason, numerous toilet manufacturers are deciding not to pursue certification. Complicating matters is the fact that some older toilets which do not work all that well have obtained certification, while some newer models that work much better do not have certification. So we have a crazy situation where some toilets that don’t work very well are certified, and toilets that work very well are not certified.

Thirdly, there is no universal agreement among government agencies on certification, what it means, what should be tested, or what should be required. In my personal experience, composting toilet certification is confusing to everyone, and being certified is in no way a guarantee that a toilet will be approved.

New Guidelines on Composting Toilets

Very detailed,comprehensive guidelines on composting toilets have recently been published. This was an extremely well thought out process, written by an engineer and peer reviewed. These are probably the best, most thorough guidelines on composting toilets available. Although published in Canada, I am hopeful they will be read and adopted widely by governments across North America. You can get a copy at the link below, print it, and take it to your local authorities when you apply for a permit. Show them you are adhering to these guidelines, and that your installation will be properly done, with no health risk possible. BC government guidelines on composting-toilets.

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