Need to build an outdoor toilet? Learn the pros and cons of a pit toilet, bucket toilet, dry toilet, or self-contained composting toilet.
Pretty much the first thing you need when building on a piece of vacant land is somewhere to go when nature calls.
Luckily, our property is only a 5-minute walk to the general store, however, there are only so many times you can show up with your 7-year-old to use the toilet before it becomes obvious that you don’t have your own!
So one of the first things we did after purchasing our property was research outdoor toilet options.
We started with three main goals:
- To build something ourselves as practice for our future building projects. Since neither of us had built anything bigger than an Ikea bookshelf, we thought it was a good idea to start with a tiny building before attempting to build a shabin.
- The design had to be something we would want to use for at least 5 years. Since it was going to be a while until we built something with indoor plumbing.
- We wanted a nice toilet, not too smelly, so that everyone would enjoy using it.
Types of outdoor toilets
I did an incredible amount of research. Read a lot of books, searched the internet, and chatted with everyone I knew who had a vacation property about how they dealt with their outdoor toilet.
It all boiled down to 4 main outdoor toilet options:
A Hole in the ground
Typical outhouses are just a seat over a hole in the ground. Beyond the need to dig a really deep hole, it’s a very simple option. Once you’ve filled the hole up to about 1 foot from the top, you shovel on a bit of dirt and move your outhouse to a new hole.
However, there are 2 distinct disadvantages to this classic outhouse design:
- The waste never composts or otherwise breaks down. This means pit toilets can contaminate the surrounding soil for a really long time. Even a 70-year-old outhouse pit will continue to leach contaminates. So you need to make sure you site your outhouse well away from any groundwater sources, streams, wells, or even gardens.
- Digging a deep hole is a lot of work. Particularly if you’re on a rocky piece of island.
Composting toilets basically involve collecting and storing waste in a way that will allow it to naturally compost over time.
Just like animal manure, human manure can be turned into rich and fertile soil. To properly compost human waste, it needs to be done in a vented container and allowed to compost until it reaches 60 C (140 F) to kill pathogens. Not that I would recommend growing vegetables in it. Unlike cows, humans consume a lot of chemicals that are excreted in our waste. And tomato plants don’t need antidepressants, thyroid medication, or red food coloring.
There are several main types of composting toilets. And it really depends on what you’re comfortable with (in terms of disposal), and what sort of infrastructure you want to build. I’ve arbitrarily divided composting toilets into three main categories.
1. Self-contained composting toilets
Self-contained composting toilets are probably what most people think of. These are thrones that are built over top of a large catchment system. They can be built inside of a house or as an outhouse that you have to hike up to.
There are a number of different ways to design a self-contained composting toilet. Here are just a few examples.
- We have Island-dwelling friends who’ve converted a large metal drum into a composter. Their outhouse sits on top of the drum. It takes them about 6 months of full-time use to fill it up. Then they remove the drum, hammer on a lid, and leave it to compost for 12 months. Because they are full-time Island-dwellers, they rotate between 3 drums.
- Some places build multi-stall toilets and only use one stall at a time. Once a toilet is full, it is left to compost for 6 months, until it can be cleaned out and used again.
- A self-contained composting toilet can be engineered for continuous use. One example is a toilet built on a 30-degree slope, where the waste gathers at the top and slowly moves down the hill. Every year or so, you can remove the composted remains from the bottom of the collection shoot.
2. Separating composting toilets
The main issue with outhouses is that there is too much liquid, which prevents proper composting. The simplest way to make a composting toilet is to separate the liquids from the solids.
Liquids are quite harmless and just need to be diluted with 4 parts water to 1 part urine before being used as a fertilizer. Solids are mixed with sawdust or something similar, then composted in a traditional compost pile.
Here are three simple examples of separating toilets.
- Commercial separating toilets are specially designed to separate solids and liquids. They have two collection areas which can be emptied on an as-needed basis (once a month to once a week depending on how many people are using it).
- A simpler version of the separating toilet is a two-bucket system. It basically involves having two buckets… one for liquids and one for solids.
- An alternative to the two-bucket system is the pee-in-the-woods system. This is particularly good for anyone with a large expanse of property. The composting toilet is only used when necessary, otherwise, everyone pees in the woods. The only trick is that pee is quite a concentrated fertilizer, so unless you have a lot of land you may end up killing everything by burning it with too much nitrogen. One option is to pee into a hay bale, which will slowly break down and turn into fertilizer.
3. Dry toilets
Dry toilets involve mixing the liquids and solids, then removing any moisture for proper composting. This can be done in two ways.
- Use a complex toilet system that has electric heat and ventilation in the catchment area to dry the liquid.
- Add a lot of a dry substrate, like coconut coir or sawdust, to keep everything dry and create air holes for improved ventilation.
For our initial campsite, we decided to build a one-bucket, dry toilet. The boys are encouraged to pee off the side of the cliff, and the girls do their business in a sawdust-filled bucket. Here is a post on our composting toilet design.