Composting toilets and city flats: do they match?

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Posted Aug 26 2021 by Michelle Smith of

Composting toilets are a great choice for low-impact living — for remote or off-grid homes, for self-contained homes, for boats, for camper vans. That much is certain. But is the ‘revolootion’ possible if you’re renting out a flat? With no garden, no plot of land to call your own, does a composting toilet make any sense?


If you’re new to the concept of a composting toilet, here’s a comprehensive introduction to the topic.

The impact of a source separation or dry toilet is twofold — no pun intended. There is a slew of individual benefits and there is a systemic effect. Obviously, there are downsides, too.

Now, when we say individual benefits, we think:

  • a sustainable, more holistic approach to sanitation (‘humanure’, liquid fertilizer)
  • saving drinking water
  • a higher level of residential independence (mobile homes)
  • aerobic composting means no greenhouse gas emissions

The downside of using a dry toilet is mainly rooted in the convenience and the established perception of its flush counterpart as the only right way. When you’re new to the source separation concept, you’re facing taboo matters. This may not be easy for everyone.

Another downer is that the flush toilet system, as flawed as it may be, is a well-regulated one. Sanitation must remain, well, sanitary. While people still happen to send things down the drain that shouldn’t go there, for the most part of the population, the use of a flushing toilet is a no-brainer.

But when it comes to the disposal of the waste collected in a dry toilet unit, regulations are all over the place. Depending on where you live, the use of fertilizers obtained through composting can be heavily restricted (and for good reasons — potential drinking water contamination being one of them). Most of the population aren’t even used to dry toilets or haven’t heard of them before. Even ‘vanlifers’ can experience shocked camping personnel, mistaking the composting toilet contents for chemical toilet waste.

On the systemic level, there have been projects and tests that tried and implemented composting toilets in blocks of flats. The results? More than just a reduction in blackwater and sewage sludge; saving drinking water and taking the proverbial load off the local sewer system were also among the reported effects.

Still, composting (or dry, or source separation) toilets can’t fully replace water toilets just yet.

So, with all that said: are there any good reasons to have a dry toilet in a city flat?

We’ve come up with 5 pretty neat ideas.


As climate change progresses, extreme weather conditions are on the rise. Even residents of areas unaffected by tornadoes or floods can experience severe problems and are advised to get prepared for emergencies. One of the most likely emergency scenarios in an urban setting is a power outage. A power outage of just a few hours can have an impact of up to days and even weeks — when it comes to restoring communications, drinking water and food supply, and, yes, the sanitation of a large city or an urban area.

Official guidance suggests having emergency kits ready as well as at least three days’ supply of drinking water and ready-to-eat food.

So a compact, portable ‘backup’ sanitation solution is what we like to see added to emergency gear.


When we seek ways to introduce more low-impact habits, saving drinking water comes to mind almost instantly.

The very idea of flush toilets operating on drinking water seems extravagant to say the least.

But in a flat, even if you don’t own a garden to really benefit from ‘humanure’ or the liquid fertilizer, you can effectively reduce the amount of flushing water. Remember: the water that operates our conventional toilets is drinking water that quite literally goes down the drain several times a day.

In a flat scenario, flushing the collected liquids into your conventional toilet every few days and disposing of the solids (dried, stink-free and tightly wrapped in a bio-degradable bag!) in the household waste will reduce the usage of drinking water dramatically.


Testing a dry toilet in your van or taking the toilet on a hiking, camping or biking tour doesn’t technically count as using it in your city flat. But it’s a good introduction and a nice acid test — also pretty helpful to master the art of the dry toilet, too!

And since many dry toilets are designed to remain portable, having one in your flat that you can move around or pack for a road trip is giving you plenty of options.


Consider this: conventional toilets are ‘out of sight, out of mind’ units. As long as you’re keeping the seat and the bowl shiny and clean, whatever leaves your body, slips your mind.

When people are relying on a dry toilet, the waste becomes a more… vital issue. ‘What did I eat to produce this?!’ one might exclaim, which often can lead to rethinking dietary and lifestyle habits.

Now, are we saying dry toilets will make you healthier? No.

What we are saying though is: awareness for our body’s needs can rise once waste can’t be simply ‘undone’ and unseen by flushing.


A toilet is a toilet is a toilet — in terms of functionality, or in terms of design, not much to tweak there. Right?

Well, when it comes to a composting toilet (either a DIY version, or a wooden one like the Kildwick FancyLoo that easily doubles as an inconspicuous seat), you can get plenty of options to create a design to match all and any of your aesthetic needs.

So what do you think? How will sanitation evolve for a low-impact future? What options do you see for urban living? Tell us in the comments.