DIY Composting Toilet Fail

*Warning-I’m talking about poop. It’s probably TMI.*


Ok, toilets and the bodily functions they take care of are gross. Black tanks are also gross. The whole situation is less than pleasant.

When we were building the bus we had to grapple with the tanks (fresh water, grey water from the sinks and shower, and black water from the toilet). They presented a difficult challenge because 1. they are really expensive and 2. we didn’t know how we would attach them to the bus. We don’t know how to weld and we aren’t at a point where we can pay someone to come out and weld them on for us. I’m sure there’s some way to bolt them in place but I would feel more comfortable knowing that they were welded on. Right now, we don’t have any tanks. Fresh water we carry on board in water storage containers. We don’t use the sinks and shower unless we are hooked up or we are parked somewhere where you can dump grey water. Black water we didn’t want to deal with at all so we decided to do a composting toilet.

I wanted a Nature’s Head composting toilet but they are $960. Excuse me, what? And that’s cheap for a composting toilet. They can easily cost a few thousand– that’s as much as we paid for the bus!. No, we are clearly not getting any of those toilets. We decided to DIY it instead. There are a lot of tutorials online on how to build your own composting toilet. They all promise to be super simple and non-stinky.

Now, I’ve used good and bad composting toilets. I know good composting toilets are a thing. Privies on the Appalachian Trail? Not so good – some of them are so bad that pooping in the woods is far preferable. They are raised little outhouses and everything just drops straight down into a mound that is not maintained in any way. They do usually have a bucket of wood chips/sawdust that may or may not be home to a family of rats so you can throw some in (wood that is, not rats) when you’re done. Composting toilet at the Len Foote Hike Inn? Fabulous. They have the whole worm system and they’ll give you a tour of their toilet system. Very breezy and not smelly. Super cool.

Depending on how complicated you want to make your composting toilet you can do the simple “go in a bucket and cove it with sawdust” route, you can add a urine diverter (according to my research it’s supposed to be the combination of poo and pee that really makes it smell) or have a pee bucket and a poo bucket, and/or you can add a fan system to help air out the whole thing. Any way you go is supposed to be smell-less if totally covered with your composting material (sawdust, peat moss, coconut coir, etc).

We decided that since we were living in a very hot and humid environment at the time of construction that we would do a urine diverter and have it go out with the grey water (pee is considered grey water). As it turns out buying a pre-made urine diverter would run us about $130 which is stupid for a what is basically a toilet seat with a funnel and hose attached to it. We decided to make our own.

We used a roof flashing that we bought from Home Depot that connects to a flexible plastic tube that connects into the pipes that drain the bathroom sink. That flashing is screwed on underneath the toilet box lid and positioned at the front of the toilet seat. The bathroom sink, pee pipe, shower, and kitchen sink all eventually meet up and drain out together from one pipe that we attach the sewer hose to. This becomes important later on.

We used the toilet once for a poo. Well Mike did. And let me tell you- it got really funky, really fast. We laid down 2 inches of peat moss (a lot of people said it was the better option) on the bottom of the bucket (as per the internet instructions) and then he covered it totally with more peat moss when he was done. There was no pee mixing in. Theoretically, it should have been fine. It didn’t smell like poo exactly but it created a very weird and very unpleasant smell. It sort of settled in the bedroom area and just sat in the humid heat (the bedroom is not air conditioned during the day) and got more funky. We got that out of the bus. I could not deal with that smell.

I did some more reading on composting toilets and learned that humidity can negatively affect everything. We were in Florida. We have close to 100% humidity all day, every day. But adding in a fan system didn’t seem very feasible because then we’d be have a giant hose coming out of the top of the toilet seat that would run out of the bus. We have a very small bathroom space. We didn’t want to cut a hole in the roof of the bus so we’d have to vent out of one of the windows which happens to line up with our canopy and outdoor seating. We’d be blowing poo air all over that area. I’m sure the neighbors would be thrilled.

Then we started having problems with the urine diverter too. First, it requires some very careful aiming. Very careful. Second, remember how I mentioned that all of the drains are connected? Well, I guess they are connected weirdly because the pee comes up in the shower unless you pour 6 cups (minimum) of water down the diverter after every pee. Maybe the pee just doesn’t drain properly and ends up sitting close to the drain for the shower. Regardless, pee smell.

Total composting toilet fail. I’m not sure where we went wrong. I could deal with pouring a ton of water down the pee drain if the poo part worked. I don’t know if it’s something wrong on our end or if everyone online is totally lying about the smell. Maybe it only works in cool, dry climates. I just don’t know.

We just bought a portable camper toilet. It has great reviews online from other people who have used it in their boats or RVs. We got a formaldehyde free deodorizer to go with it. It basically has its own fresh water and black water tank and you just empty the black tank out into a regular toilet and flush it down.

I really, really, REALLY hope it works out. The bathroom is so cute but it makes me so irate.


Fingers crossed.






  1. Keep in mind that almost all odor problems relating to composting toilets result from the contents being too wet.

  2. Hello. And Bye.

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