The other day I was sitting at a table with several other homeschool moms when someone said her family was interested in a compost toilet. Then, to my shock, someone else grudgingly admitted she’d been talking to her spouse about it, too.
It’s not surprising that the interest was grudging. We’re all naturally averse to dealing directly with human waste, especially if we can just flush instead, especially if we’ve just finally finished changing diapers. What’s surprising is that I’m used to being the most out-there of my eco-conscious friends, and here they were genuinely asking what it’s really like to live with a compost toilet. And toddlers.
I’m not going to share my exact protocol because even though it works quite safely for us, I’m not completely confident you would go off and apply it exactly like we do in circumstances that might be different. I’m not keen on being sued or even worse, being responsible for someone getting sick. If you’re ready to dive in, great! But don’t take advice from me, take it from people who feel legally and ethically capable of giving it, such as Separett or the Humanure Handbook. This is just an overview for the curious and uncommitted.
Why even consider having a compost toilet at all? In the global north, modern sanitation has gotten rid of cholera, typhoid and many other nasties from which thousands upon thousands of people used to die agonizing deaths. That’s not something to sneeze at. Keeping our rivers uncontaminated with human sewage is basically the litmus test for civilization, and it’s absolutely essential that we continue to do so.
But it seems very strange to me that the way we’ve chosen to do it is to spend energy making chemicals to treat water all the way to drinkability and piping it many miles, only to re-contaminate it. Pooping in water increases by many times the volume of hazardous substance that must be treated.
It also worries me that our critical sanitation is dependent on fragile modern systems. When the power goes off for a while, hygiene is often the second emergency (right after healthcare). It seems to me we should have backups in place, which rely only on local knowledge and locally available materials.
An acceptable place to poo. I built the box. You might notice a scuff mark on the first of the lid. That’s from where the children slammed the lid into the earthen plaster behind it, and our spectacularly stain-tastic local red clay worked itself into the plastic. No amount of bleach can remove it.
Our compost toilet is a urine-separating model from Separett. It’s really just a specially-made seat, which captures the liquid waste portion in a sort of funnel and allows the solid waste portion to drop into a bucket. When I don’t need fertilizer, I route the funnel outlet into the septic tank. It could be safely routed to a grey water system feeding a mulch basin.
The county made me install a septic system even though our house produces no black water (a.k.a. water contaminated with feces). It cost four thousand dollars, and it treats our grey water from the sink and shower. Yes, I’m aware I could have built a system that does the same for about $100 and a lot lower environmental impact, but that would have been illegal in my area. Before you call social services on me for having a compost toilet and children, you should know our toilet has approval from the building department.
When I need fertilizer, I route the funnel outlet into a container, dilute it by about eight times, and pour it in the garden. This has to be done every day because while urine is sterile when it exits your body, it gets smelly fairly quickly thereafter. You can apply it on the first day, or you can store it for a month while it undergoes a change from very acid to very basic, and then dilute and apply it. Being lazy, I skip the storage.
Either way, urine has an excellent nitrogen/phosphorous balance and is safe to use on plants when properly diluted. It forms an important component of our completely free, completely local fertilization scheme. If you don’t have a urine separating toilet you can still use urine as a fertilizer, just catch it in a jar or other container. Yes, even when fresh it smells, but certainly no worse than organic fish meal. And in contrast to fish meal, urine seems to keep critters out of the garden, rather than inducing the dog to dig up my tomatoes hunting for rotting fish.
Did I mention it’s free? Inorganic fertilizer costs money, it’s made by drawing nitrogen out of the atmosphere using pollution-emitting natural gas, and it’s choking our waterways and poisoning our oceans. Urine can feed useless bacteria in a septic tank or water treatment facility, ultimately returning its nitrogen to the air, or it can be captured by the soil critters and plants in your garden, and do you some good. I know which one I prefer.
As for the solid portion, every time a “deposit” is made we cover it with a handful or three of wood shavings, a waste product that we haul for free from our local lumber mill. Unlike with a flush toilet, the room will stay smelly until you cover the poo. Just like with a flush toilet, the room will stay smelly until you clear the air. We just open the window for a couple of minutes.
Our bucket fills up about once a week. I put a lid on it, swap in a clean one, and take the full one to a secluded location to rest. Inside, the bacteria already present in the poo get to work decomposing it. As they do, they use up all the air in the sealed container, killing anything that requires oxygen. After the rest period, I take four buckets at a time and mulch a tree with them. When I open the buckets they are already smelling more composty than bathroomy. It’s not the world’s nicest smell but not a puke-inducer, either. I lay part of a cotton sheet from Goodwill over the pile to deter flies, and cover that with grass and weeds cut from the field around the tree.
The buckets get sterilized and de-smelled with two rounds of dish soap, one round of bleach and time in the baking sun (not too long or the plastic degrades). By the time they make it back into the house, you would have to stick your head inside the bucket to detect any faint hint of a bad smell. I use catchment water off the barn roof for washing, not treated city water. The whole mulch-and-wash procedure takes me about one hour, once a month.
That’s all the practicalities. Now to the important stuff.
Is a compost toilet smellier than a flush toilet? I have a super-sensitive nose, but I’m just not emotionally revolted by smells in the way some people are. To my nose, it’ll be slightly smelly if the children refuse to send a cup of water down the funnel after they pee, or if the humidity gets really high, in which case the whole world smells unpleasant to me. But because the urine and the poo never meet, it can’t take on anything like the stench of an outhouse. If you have a super-sensitive nose and very strong opinions about smells, maybe it’s not for you.
Is it too much work? As it see it, the main benefits are: 1. being able to sit more comfortably while I collect the urine we need for the garden, and 2. having a sanitation scheme that we are familiar with if the power and water go off for a while. In my opinion, this is not too much work for those benefits, and it has the side benefit that the trees get mulched (I don’t use toilet mulch on trees that are producing food anytime in the next year). If there’s no one in your house who can comfortably lift four 15-to-20-pound buckets and schedule an hour during the right week to do so every month without fail, this probably isn’t for you.
What about little kids? Oh man. Little kids and toilets. There are just so many different ways it can go wrong.
A major plus of toddlers + compost toilets is that nothing of value can be flushed down a compost toilet, no matter how hard they try. A major drawback is that toddlers + wood shavings can be a spectacular mess. My 7-year-old does his own shavings, but my 4-year-old just does her own cup of water after peeing, while I do the shavings for her. I’m not sad about this because I like to keep an eye on her digestion. If you’re so done diapering you never want to see another poo but you still have a kid under five, maybe wait on the compost toilet.
The shape of the funnel means that peeing while standing causes splashing, so people with a penis are encouraged to sit. This means I never have to clean up little boy splashes, which is awesome! At my house, anyone who really prefers to stand is welcome to select one of many lovely trees. This keeps critters away from the house, too.
What about pests? The shavings keep flies from directly accessing the waste, and prevent houseflies from laying eggs. They don’t prevent fruit flies from laying eggs, and fruit flies areattracted to it. They don’t breed in our house but come in from outside during the hot months. I trap them with sticky tape and kombucha traps, but some still reach the bathroom. I switch out the bucket about every six days in summer so that no egg can reach maturity (7 days at 76 degrees), just to preclude the possibility that an egg could become an adult in the bucket and thereby bring bacteria out of it (maybe not straight to your toothbrush like a flush, but still, yuck).
The compost process kills them, so the bucket actually acts as a very effective fruit fly trap. Because adults can’t get to the waste, they don’t transfer any harmful bacteria to any other surface. We haven’t had so much as a tummy bug in going on three years of composting. But fruit flies offend me on a very basic level, and just seeing their little buggy butts in my bathroom is my one and only real complaint about my toilet. I’m not about to rip it out and put in a regular one over this, but if you have fruit flies in your ecosystem and feel the same as I do about them, maybe a compost toilet isn’t for you.
What about *gasp* company? If you’ve got a compost toilet you have to explain it to every new visitor right when they arrive, and reassure them that it’s okay to poop. This is a little awkward for unsociable me, but I’ve never had anyone fail to get with the program. Kids have to be reminded, of course. Maybe guests are laughing at me and my bucket toilet, but not (so far) to my face. If you’re too squeamish to get the information across, maybe a compost toilet isn’t for you.
Also, our system is just for low-volume household situations. If you were dealing with The Public you would want a heat-treatment backup, lest you end up like the streets of San Francisco.
All that aside, there are a couple of miscellaneous advantages to the compost toilet I really appreciate. It’s not any more arduous to clean than a regular toilet. I just give it some bleach and wipe it out with a rag, with maybe a splash of CLR and an extra scrub if there’s scale building up at the bottom of the funnel (this happens when children don’t flush). I really like not needing to buy or store a toilet brush, which always grossed me out. It also can’t get clogged, so I no longer own a plunger, which I also hated. And there isn’t any unpleasant splash-back effect. In these ways, I find a compost toilet more self-contained and less disgusting than the flush option.
In summary, we have a compost toilet, we don’t hate it, and you can have one, too. If you want. Do you already have one? Is your system different than ours? How do you like it? Tell us below.