Are Composting Toilets Legal in Tiny Houses?

If you’ve been asking yourself are composting toilets legal in tiny houses, you’re not alone. Our friend Richard Brunt, who we purchased our Separett composting toilet from a few years ago, wrote this article to discuss the legalities. Composting toilets allow many of us tiny housers to have a safe way to manage our waste but there’s often a question of whether they’re legal or not. If you’ve been wondering yourself, read on for a professional perspective on the topic. 

composting toilet in bathroom

Our Separett composting toilet in hOMe. Still going strong after nearly 3 years.

Are Composting Toilets Legal in Tiny Houses?

One of the most commonly asked questions I receive on composting toilets is “are they legal?” This is not a simple question to answer. Regulations on composting toilets usually don’t exist in the building codes. And does a tiny home on wheels even fall under the building code? Since the clerk at the county office can’t find anything about it in the books, they might just say no, composting toilets are not legal. Frustrating.

So, what action steps should you take if you’re trying to legalize your composting toilet? First, determine if you need a permit by researching your local building department. If you don’t, you are free to install your composting toilet. If you do, don’t despair – people get permits for composting toilets all the time. However, they sometimes have to go beyond the receptionist, and speak to a department head in engineering, building or plumbing. If you can show people with decision making authority that you are responsibly and intelligently dealing with the output of your toilet, approval might come easily.

In certain situations, especially with new home construction built under the building code, the building inspector may insist on an “approved” composting toilet system. What exactly this means can vary from place to place. Al- in-one composting toilets, that combine solids and liquids in one tank, often  need an NSF41 certification. NSF41 does not apply to urine diverting toilets, which might need an ETL certification. The inspector will likely be unaware of this distinction, so you might have to inform him or her of this.

For a composting toilet company, receiving certification  can be incredibly expensive. Fees can be $40,000 for initial certification and then very expensive for yearly renewal in order for the certification to remain “active”.  As a consequence, some manufacturers are deciding not to obtain certification. They see it as a money grab, or a scam. Ironically, some older toilets, which do not work all that well, have obtained certification, while newer models that work much better do not have certification.

Many jurisdictions don’t care about certifications, because they are (rightfully) far more concerned with what you do with the output of your toilet. No certification will guarantee the user is going to properly dispose of the waste. At the end of the day, that is what everyone wants – proper disposal of waste without pollution or health risk.

Always be prepared to show your building department your waste management plan: what you will do with the urine and solids once they come out of the toilet. If it is a sound plan and clearly illustrates that you won’t be contributing pollution to your lot and surrounding areaa, you may well get approval.

In cities and towns where sewers are available, authorities may require that plumbing for a flush toilet be installed in the house – even if installing a composting toilet. This includes a drain pipe, vent stack and water supply lines. Their rational is, they don’t want to force future home owners to use a composting toilet.

Concern about composting toilets by authorities is completely warranted; sewage waste has been shown to contaminate local water systems and handing over the disposal of this material to the homeowner is something they take very seriously. A careless or lazy person might not deal with the output of their composting toilet appropriately. That said, if you propose your project with a clear, safe, and well thought out disposal plan for the waste from your composting toilet, you have a very good chance of receiving approval from your building department. 

Richard Brunt is the owner of Composting Toilets USA. He distributes Nature’s Head and Separett composting toilets. He can be reached toll free at 1 888 361 0014. His customer service is outstanding and there hasn’t been a question we’ve thrown at him that he’s not been able to answer well. 

You can read our full review of the Separett and watch a video on how it works by clicking HERE.

11 Responses to Are Composting Toilets Legal in Tiny Houses?

  1. Mike Payne February 10, 2017 at 1:20 pm #

    BC has started to address the issue, and has published a guidance paper for how Composting toilets fit into existing code, and how it should be addressed where code doesn’t sufficently cover it. The problem is that it is prepared by the BC Ministry of Health, and has not found a place into BC code or Municipal codes yet as it is still an emerging area (as is our dwellings).

    It is written by an engineer and very technical, but it the officially recommended practices within BC for now.

    www2.ov.bc.ca/assets/gov/environment/waste-management/sewage/provincial-composting-tiolet-manual.pdf

    • Richard Brunt February 14, 2017 at 6:00 am #

      These guidelines are incredibly thorough, to cover all situations. I have been in touch with the author, and we hope to have a simplified version that is applicable to common, self contained, urine diverting toilets that most of us use. In a nutshell, it does say that we can dispose of our solid waste in compost bins (although he recommends letting it sit for two years – this is probably because in the cooler Canadian climate things may not break down as fast, and also, by the author’s admission, it includes a very, very wide safety margin). Stay tuned for more practical interpretations of this report.

  2. Mike February 10, 2017 at 5:20 pm #

    What is the proper disposal method? A contained separate outdoor composting pile?

    • Richard Brunt February 14, 2017 at 6:03 am #

      In most of the world, they recommend letting the solid material sit, in a dry place, for at least 6 months. In my experience, the best way to do this is with two sealed composting bins, that cannot leach anything onto the adjacent ground. When bin number one fills up, (and that should take 6 months to a year) start using bin two. When bin two is full, you can put the contents of bin one on non edible plants.

      • Mike February 14, 2017 at 7:07 pm #

        Thanks Richard.

  3. Janise February 10, 2017 at 5:40 pm #

    Mike – that’s what I always want to know too. What ways are people dealing with their “output”.

    • Richard Brunt February 14, 2017 at 6:07 am #

      Please see my reply above on the best way to deal with the output. It’s easy, but you do need to be very careful and do this correctly

  4. Ingrid Stanway February 11, 2017 at 2:29 am #

    The humanure handbook is a fantastic read….gives many ideas on disposal

    • /bob February 11, 2017 at 10:22 am #

      +1 on the Humanure Handbook! It was amazing to me to read about how many people who THINK they know how to compost really don’t do it right, resulting in failure and disappointment in the results. On the Separett web site (link in blog entry above) Richard explains that the Separett is really just part one of a two part composting system. The second part is a compost bin of your choosing where-in you dump the “material” from the toilet bucket to finish the compost process.

  5. Megan Zopf February 11, 2017 at 12:46 pm #

    Does anyone ever consider what happens to disposable diapers? The urine is NOT separate and it gets thrown into ordinary trash. I think compost toilets are a lot better than what happens with diapers. My kids are all grown up now with the youngest one almost 40. I am in the middle of building my tiny house and I will be using a compost toilet. I hate the idea of a septic system!

    • Richard Brunt February 14, 2017 at 6:11 am #

      Urine is easy to deal with, as it’s not “sewage” and is practically sterile. However, it does contain a lot of nitrogen (which makes it excellent fertilizer if diluted with water), and which means it can’t end up in fresh water – it will cause an algae bloom. So people living close to the waterfront might not be able to run the urine drain line into a simple French drain. They’ll have to dispose of it a significant distance from water.

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