Straight Poop: The Pros and Cons of Composting Toilets

If there’s one aspect of a tiny house that gets the most attention, it’s often surrounding the toilet. We take our thrones seriously, and a clean bathroom is a must for most folks. A good many of the homes we feature have a composting toilet, and today I wanted to explore some of the pros and cons of these, along with how they work.

“The current technology of “waste disposal” is still fighting a war against nature, built on fragments of nineteenth century science not yet integrated into an understanding of life processes as a unified, but cyclical, whole.”
– Van Der Ryn, The Toilet Papers

You may be familiar with composting toilets from state parks, campgrounds, and porta-pottys. These receptables work in much the same way as the ones you see in tiny houses, although the ones found inside homes are usually a bit more refined in the way they work. At their core, composting toilets break down human waste, toilet paper and bulking materials (wood shavings, sawdust) into compost. An important note worth sharing right away – DO NOT use the compost on any edible gardens.

The three primary goals include:

  1. Containing and destroying harmful pathogens that could otherwise make humans sick. This is done in a way that also avoids contaminating the natural environment surrounding us.
  2. Transferring nutrients in human waste into an end product that’s not offensive, and which can be used with minimal risk to amend soil for horticultural plants and trees.
  3. Evaporating the liquids.

Self-contained: If space is limited, this is usually the choice. These systems rely on a toilet seat and catchment chamber in one unit. Some models have a urine catcher separate from the other compartments, which helps reduce the smell a great deal.

Centralized: These types separate the catchment container from the seat, often relocating it to the basement or outdoors. Also known as a “remote” unit, there are several types of centralized systems out there.


  • Low cost and often low maintenance to install and maintain. Compared to the cost of a septic install ($1500+) the composting toilet is often cheaper, easier, and faster to install.
  • Little impact on natural surroundings. In fact the compost can aid in the growth of plants.
  • Less water waste. The average US citizen flushes about 7,665 gallons of water down the tubes each year.


  • Depending on the style you have, the smell can be an issue. This is usually the case on centralized systems, but not so much an issue with compartmentalized ones. Certain products like “poo porri” can also help minimize smells 🙂
  • Guests may think it’s a bit weird. They’re not used to using a toilet like that so it may be a bit strange to them, but then again, if they have a real problem with it.
  • Composting toilets are generally larger than regular ones, due to the compartments and additional components necessary to manage the waste.

Helpful tips

  • Often the manufacturer includes a package of composting activator, a combination of beneficial microbes and sometimes wood chips. You can dump this into the tank and it will help create a good environment to break down the waste.
  • For systems that use a tumbler style catch bin you will need to crank a handle on the toilet to mix the composting waste.
  • It’s advised to use special types of disposable toilet paper designed to break down in these systems but in general most types will decompose without issue.
  • In cooler weather during the winter months the compost activity declines or comes to a halt. If you have a heating element this won’t be an issue.
  • You can use the finished compost on trees, shrubs, and other plants but DO NOT use it in your vegetable garden.
  • Check health and safety regulations in your area. If you’re in the city confines you probably can’t use a centralized system, but that’s dependent on your local health and safety regulations.

Futher Reading About Composting Toilets

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Sep 23, 2014 / by / in

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