3 Years Sailing with a Boat Composting Toilet
Composting toilets for boats have become much more prevalent in recent years. While they’re not for everyone, a growing number of cruisers and day sailors have started opting for them over traditional marine heads.
It’s easy to say, “Composting toilets are great for boats!” but honestly, we don’t live on a boat, so we wanted to talk to someone who does and who has been using one for boat life.
We had the pleasure of speaking to Liz, who is sailing around the world with her boyfriend and her dog, and, of course, uses a composting toilet on her boat.
Read on to learn her tips and tricks and why she loves her toilet setup for her boat adventures!
About Liz and Where She “Goes”
I’m a full-time cruiser who has spent the last three years sailing down the west coast of the United States and through Central America and the Caribbean. We replaced our marine head with a composting toilet before setting sail, and have not regretted it! I’ll be sharing my personal experience with using a composting toilet on a boat, and some tips and tricks we use to keep things running smoothly.
Why a Composting Boat Toilet?
Why would someone choose a boat composting toilet over a traditional toilet? How easy is it to manage, and is it better or worse than a regular marine head? Are there downsides to choosing a composting toilet for boat life, and if so, what are they?
Here are some of the reasons we chose a composting toilet and why we still love it.
Simplicity
A traditional marine head is a complicated system. Hoses, pumps, valves—and, depending on the type of toilet, possibly a vacuum or jet action system. That’s a lot of parts that could potentially go wrong. It makes maintenance more complicated and repairs more expensive.
It also takes up space. On our boat, the hoses from the original head to the waste tank had been run through bathroom cupboards, as there was nowhere else for them to go. This made the cupboards unusable for storage. When we ripped out the old head and all the hoses, suddenly, we had storage space in the bathroom!
Smell
Contrary to what you might be thinking, a composting head smells way better than any traditional marine head I have ever smelled. Our boat has no “boat smell.” At all. Ever. Zero. It’s the only boat I’ve ever been on that doesn’t.
The reason for this is that a composting head separates liquids from solids and doesn’t create sewage. Sewage is what you get when you your mix solids and liquids, and it smells. Solids on their own dry out and don’t smell.
Also, in a traditional marine head that uses salt water to flush, microorganisms from the water die in the pipes and build up, creating a smell when mixed with waste down the road. This is what creates that classic “boat smell.” A composting toilet for a boat uses no saltwater and has no hoses.
Water Use
While we’re on the subject of water: a boat composting toilet doesn’t use any. Salt or fresh. It does use a little electricity because you have to run a fan to draw moisture out of the solids bin, so keep that in mind.
Convenience
We empty our head about once a month, because with two of us aboard, using it daily, it fills up. However, day sailors and pleasure cruisers who don’t use the head very much can leave a composting head for months without having to empty it. In fact, the longer you leave it, the better—the solids just continue to break down. Other sailors have told us they forgot to empty theirs at the end of a season and let it sit upwards of six months with no problems.
What Considerations Do You Need to Make for a Composting Toilet for a Boat?
I won’t pretend there are no problems at all with our boat’s composting toilet. As with everything, it requires some compromise and trading off.
Emptying
If you’re like us and need to empty the head frequently, you’ll find that the solids don’t completely compost. So you’ll be getting up close and personal with actual humanure. To be honest, this isn’t as gross as it sounds. We just dump it into a heavy duty garbage bag and dispose of it with the rest of our waste. (unfortunately we can’t add it to a compost bin out here on the ocean!)
Sometimes we clean the bowl, but honestly, you don’t have to do that—any leftover humanure will just continue to break down for the next month.
Bugs
We live in the tropics, and bugs are an issue. Part of the reason we empty monthly is because if we let it go any longer, we will get bugs. We use diatomaceous earth to mitigate the issue, which works okay but not perfectly.
In cooler/drier climates, this isn’t an issue, but if you plan to cruise the tropics, be aware that you’ll need to prepare for bugs and be thorough about cleaning when you empty to get rid of any eggs.
Explaining it to Guests
If you have people staying on board for multiple days, you’ll need to explain to them how to use the toilet. Depending on your comfort level, this might be a bridge too far. Most sailors are used to having to do this, but it is a bit more involved than using a regular marine head, and guests may not be comfortable with it.
Having said that, there is much less chance that your guests are going to put something in the toilet that screws things up. You can put toilet paper, sanitary pads, and other things in the head without damaging anything. We don’t recommend you do this, but it’s nice to know nothing will go drastically wrong if it happens.
Cost
Composting toilets for boats are more expensive than most marine heads. Honestly, I don’t totally understand why this is, when they are so much simpler, but some models can run twice as much as a basic manual pump marine head.
What’s the Best Composting Toilet for a Boat?
Whatever fits within your budget, space constraints, and desired aesthetics… in other words, the best composting toilet for YOUR boat might be different than mine.
Some things to consider when selecting yours are:
- Price (what’s your budget?)
- Size and shape (where will it fit?)
- Capacity (how many people are using it?)
- Ease of use (how hard is it to clean?)
- Functionality (to agitate or not?)
Other Boat Composting Toilet FAQs
Still have questions? I got you! Here are some of the most common questions I get asked about our toilet setup:
What Medium Works Best?
We prefer coconut coir (coconut husks that you buy in bricks.) You can also use sawdust or pet bedding. We like coconut coir because it comes in very compact bricks that are easy to store in bulk. (Which is the best Composting Toilet Medium?)
How Do You Manage Moisture in a Boat Composting Toilet?
Use as little water as possible when setting up the toilet. We mix our medium very dry. You’ll have to experiment with this to determine what ratio of water to coir works best for you. For us, it’s something like 2 cups per brick.
How Do You Manage Flies?
We mix diatomaceous earth into the coir when we set up the toilet for the month. We empty the toilet about every 4-6 weeks (any longer, and flies will start to invade.) When we clean it out, we make sure to thoroughly clean the top half of the toilet, where eggs are likely to be tucked into corners.
How Do You Dispose of Liquids?
Easy peasy! Just dump them over the side. If we’re in a place where we don’t feel comfortable doing that, we’ll sometimes also dump ours down the bathroom sink while running plenty of water, and follow up by cleaning the sink.
One thing I will say is that the liquid tank fills up fast. It’s probably the only major downside of a composting toilet system. We pee over the side a lot. It works fine for us and means we don’t have to empty the tank very often.
Can It Handle Everything?
Actually, yes! As someone who spent a year in Mexico and experienced “Montezuma’s Revenge” more times than I would like to admit, I can personally attest that the toilet…um…holds up.
Are You Ready for a Boat Composting Toilet?
The decision to replace your existing head with a composting toilet will ultimately come down to your willingness to make the tradeoffs inherent in each system.
On the one hand, a composting toilet for boat life means no maintenance, less water use, easier repairs, no smell, and fewer emptying trips. On the other hand, you will be dealing more directly with your humanure, and depending on where you sail, you may have to worry about bugs and the moisture level in the toilet.
We personally love our Composting Toilet and would never go back. But we understand that a composting head isn’t for everyone. Ultimately, it’s the kind of thing you may just have to try out and see if it clicks. If it does, you’ll be glad you did it!
