Top 10 things to know before buying a 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 an 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.
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.