Top 10 things to know before buying a composting toilet


Top 10 things to know before buying a composting toilet 

Separett Composting Toilet

Separett Composting Toilet

Gain important knowledge, and avoid buying the wrong composting toilet.
  1. Will it stink inside? Absolutely not, as long as you have a toilet with a vent and fan. The fan draws air into the toilet, and exhausts the stinky air outside. It should never enter the bathroom area.
  2. Will it stink outside? There can be a bit of odor where the vent terminates the home. This is less with a urine diverting toilet. The vent should not terminate near a deck, door, or opening window. If in doubt, run the vent up to the roof line. Do not believe anyone that tells you that you don’t need a vent. There is moist, stinky air in that toilet and it MUST go outside.
  3. How much does a good composting toilet cost? You should expect to pay between about $950 and $2000 for a high quality composting toilet with a vent and exhaust system.
  4. Is it legal? Probably, but legality varies widely. Usually, permits can be obtained (if necessary) by approaching senior managers at the county office. Inspectors generally can’t approve them, because it’s not in the code book. You can read my detailed post on the subject here. Are Composting Toilets Legal?
  5. Is it a urine diverting design? The better toilets separate urine from solids. Urine is practically sterile, and very easy to dispose of safely. Solids begin drying out quickly, lose odor, and also become easy to dispose of. When you combine urine and feces in one tank, it becomes much more difficult. You might need powerful heaters.
  6. What do I do with the solid waste? You need to think about this carefully, because human solid waste can pollute the water and make people sick. Store the waste in a compost bin outside (I like the rotating bins). Choose a bin that is sealed, and cannot leach any liquid on to the ground (but is not airtight). Ideally you will have 2 bins. Once the first bin is full (and that can take a year or more depending on the number of users), start using the second bin. When the second bin is full, the contents of the first bin can be placed on non edible plants.
  7. How will I vent it? Vent it through the wall or roof. Most of what you need should be supplied with the toilet.
  8. How will I get rid of the urine? Urine can go into a gray water system (with the shower or sink water), or it can be drained into a rock pit.
  9. How often will I empty it? The smaller composting toilets like The Nature’s Head for 2 people need to be emptied every 3-4 weeks with full time use. The larger toilets like the Separett will be emptied about every 3-4 weeks with 4 people using full time. This varies with the amount of toilet paper that is used.
  10. Is there excellent service and support? Customer service and support is critical when buying a composting toilet. Make sure you can reach the appropriate people directly and easily. You will have questions. It’s best to buy from someone specializing in composting toilets, rather than a hardware store, or someone selling all kinds of products. You need expertise here. It’s critical to get the right toilet, and to install it properly. A person that also sells solar panels and tiny home gear may not have the requisite knowledge.

If you have other questions on composting toilets, please let me know.


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4 thoughts on “Top 10 things to know before buying a composting toilet

  • Joan

    Hi- we are considering the natures head toilet. We are building a barn with a loft that will have some basic living quarters as a weekend getaway . We are thinking we would build a small bathroom in the lower level of the garage. It will mostly be used on weekends in the summer & fall & occasionally in the winter. With just 2 of us most of the time. I’ve watched the you tube videos & read the directions. It looks pretty straight forward. My husband is a little worried about the venting system. He doesn’t want to cut a hole in the steel building . Wondering if we could rig it to vent it out of a small section of the window that we would insulate / engineer . Or does the venting system need to really go all the way up to the roofline. I am assuming if u don’t go to the roof line anyone walking past a low vent would smell the poo fumes- am I correct? And I assume the fan runs constantly ? We will have electricity In the barn , but that fan runs all the time even when we are not there, am I correct? If the fan doesn’t run you will have poo fumes in the barn , am I correct? Thanks – sorry if these are silly questions, just doing my homework before we purchase & make sure we choose the right one for us.

    • richardbrunt Post author

      You don’t usually have to go up to the roof line for venting. Out the wall is actually better (shorter). There is a small amount of odor that comes out of the vent, but not much. I’d definitely try your idea with the window. I know a guy that put a tight fitting piece of plywood in a window opening, sealed it well, and vented through that. It worked fine.
      If you do notice odor, you can put an elbow on the vent and run it a few feet up, on the outside of the building.
      The fan runs 24/7, but with a vent there will still be air moving through the toilet. There is a good chance you will smell nothing if the fan is off for awhile.

  • Kim Galatolo

    I am purchasing a tiny home with a Separett toilet installed last year. I was told they use liner bags and coconut coir with this system, yet nothing on your blog refers to that. Is that overkill, or an option or?

    • richardbrunt Post author

      The Separett uses compostable liner bags but not coconut coir. (The Nature’s Head is the toilet that uses coconut coir). Use good quality compostable bags, and double bag it. I like Glad Tall Compostable Bags.