When you hear the words “compost toilet,” there’s a good chance you immediately begin imagining some sort of terrifying box with a hole in it you want nothing to do with. That’s certainly what I pictured. I envisioned a pungent wooden contraption used primarily by log-cabin dwelling, tie-dye clad, shoeless men who used to follow the Grateful Dead. So, when I was asked to interview the manager of a compost toilet manufacturer, I was fully prepared to respond to everything he said with, “Oh, cool. Gross.”

What are composting toilets?

Compost toilets, if you haven’t already figured this out from context clues, are toilets that collect your waste and break it down into compost, rather than using a plumbing system like we have in NYC to sweep everything away into a septic system or a sewage grid. You simply remove the dry compost from the toilet a couple of times a year. But, the idea of waste being swept far, far away just seems much more comforting than the thought of it being naturally broken down inside one’s own home.

Do compost toilets smell?

It turns out, however, that compost toilets are – and I can’t believe I’m saying this – not gross. I spoke to Fraser Sneddon, manager of the Sun-Mar Corporation, and immediately got down to the most important question: Do compost toilets smell? I figured if the answer to that question was yes, there wasn’t much need for any other questions.

Fraser explained a couple of things right out of the gate. First, he mentioned, “All of our models have a vent stack. The venting does help insure we have no odor.”

Vent stacks

The vent stacks, which lead to outside of wherever the toilet is housed, create negative pressure inside the toilet forcing air to always travel outward. Some do this by relying on the natural air movement outside, while others have a continuously running fan to help things along. In addition, Sun-Mar provides their customers with an additive called Compo-Sure (clever name) to ensure that your waste decomposes using aerobic bacteria rather than anaerobic bacteria. It turns out that the smell you imagine when you think of rotting human waste (which I’m sure you do regularly) is mostly caused by gases released by anaerobic bacteria.

Compost kitty litter boxes?

I also watched a few videos online about compost toilets; everyone seems to be in agreement that odor is not really a factor. However, one person in a video did refer to a compost toilet as “essentially a human kitty litter box.” So, obviously, I then asked Fraser Sneddon why his company didn’t also make compost kitty litter boxes. I have no doubt that the handlebar- mustached youth who reside in my Brooklyn neighborhood would waste no time buying a compost kitty litter box they could use to help fertilize their rooftop gardens where they grow thyme and have kombucha parties. Fraser politely chuckled and responded that it’s something Sun-Mar might be interested in for the future. Frankly, I don’t think he took my idea all that seriously.

Practical uses

As long as compost toilets don’t smell, though, it’s worth getting into their practical uses. Fraser was very honest about this. Compost toilets are, after all, more expensive than traditional toilets. He explained, “There’re applications where they make sense, and applications where they don’t always make sense. If you’re in a situation where you have a house, and it’s got toilets already plumbed in, you’re going to have to be connected to the grid anyway. So, if that plumbing is already in place, to put a composting toilet in is going to be more expensive.”

But Fraser went on to describe other instances where a compost toilet absolutely makes sense. “In North America, close to 25% of the population is on septic systems. Septic systems don’t last forever.” A compost toilet, because it is self-contained, can relieve pressure on and greatly extend the life of an existing septic system. Also, in places with no easy access to pre-existing plumbing, compost toilets are an obvious choice. For example, if you were to build a pool shed in your back yard, and didn’t want to go through the process of linking that shed to your piping system, you could simply have a compost toilet installed in as little as half an hour. Even if your house is fully plumbed, a compost toilet might be a good option if you have an elderly parent move into your house and you want to install a toilet closer to their bedroom without re-piping your house.

Greater efficiency

On top of their practical uses, compost toilets are also just more efficient than a standard toilet. According to Sun-Mar, “Toilet waste typically accounts for about 30-40% of your household water output.” Some Sun-Mar models use no water at all, and the ones that do only use one or two pints per flush. Even a low flow version of a standard toilet uses about 1.6 gallons. Furthermore, there’s little to no chance of failure with a compost toilet, while septic systems are notoriously unreliable and can pose environmental risks when they leak.

Would I buy one?

At this point, It might seem like I’m suddenly getting a little sycophantic about compost toilets. I don’t mean to be. I mean… I am never going to buy one. I live in a New York apartment and I would have to write A LOT more articles about compost toilets before I had enough money to hire a carpenter to build a place in the country where I’d actually consider having one. That being said … there are some nice looking compost toilets.

There are a few different models of compost toilets that each have benefits for different kinds of scenarios. But, bottom line: compost toilets don’t smell, and they look like well-made computers. Whether it’s practical to buy one or not is something for you to figure out on your own, but at least now you know that they aren’t terrifying.

Updated June 19, 2018.