How Do Composting Toilets Work?

Compost toilets are very effective at what they do. But how do they work?

I used to wonder how composting toilets worked when I first started composting. After all, feces should not be added to a compost pile.

But composting toilets, as you shall see, have a unique technique of producing compost and are excellent for the environment.

Different Types

  • Self-contained system – For all intents and purposes, the toilet is a single entity. This system may be the best option if you have limited space or live in a multi-story home.
  • Centralized system – All waste is flushed to a big, centralized tank that is put either under your home or outdoors. There are several different types of centralized systems, each with its own technique of flushing waste and number of storage chambers. A centralized system is more like a regular toilet and, depending on the situation, may give you a better experience. 

How They Work

The primary goal of a composting toilet is to turn human waste into soil. 

In order to function, it must keep moisture out. While you can flush it like a traditional toilet, a composting toilet works by diverting your waste and urine into two different containers.

You’ll need to spin down your waste from time to time to assist the composting process. You’ll also need to add a carbon-rich substance to help the breakdown of waste materials. (Sawdust and coconut shavings are the usual additives.)

The bin should be changed once it is full, which usually takes about 4 to 6 months. From there, it often takes another 6 months before it becomes spreadable compost. 

compost machine for toilet waste composting


Useable Compost

When a unit reaches capacity, it is emptied. If your system is operating effectively, you will see safe, nutrient-rich soil, similar to compost, with no visible or odorous traces of human waste. You can use it just like you would other soil.

Purchasing a system that is suitably scaled for your needs can assist you in avoiding frequent emptying (like once or twice a year in some cases). This gives the system plenty of time to complete its task and produce an excellent supplement for your flower garden or bushes.

Very Little Smell

Contrary to popular belief, composting toilets can actually smell nicer than traditional ones. This is because sewage odors are formed when urine and feces mix. Since these components are separated in a composting toilet, there is less odor. Additionally, a fan is used in some systems to provide even more ventilation.

Another benefit is that there is no poopy water ‘splash back’ that can occur with traditional toilets.

Saves Energy and Water

The benefit of using a composting toilet is that it can save thousands of liters of water per year. You’re also saving money at the local garbage facility, which spends a lot of money every year to break down human waste.

Simple to Install

Installing a composting toilet is a rather simple operation, especially if you choose to go with a self-contained system. Split systems take a bit more effort to install.

A portable and clean tiny toilet


Requires a Small Amount of Power

These systems utilize exhaust fans to reduce odors. As a result, they use a little electricity, which ordinary flush toilets do not.

Involves Manually Handling Waste

Because garbage isn’t washed away, composted waste (which resembles topsoil) requires some physical management. Some individuals are disgusted by the prospect of having to deal with garbage, even if it is in a different form.

Higher Initial Costs

Composting toilets are initially more expensive, but because you are not reliant on city water, you should save money in the long run.

How Much Do They Typically Cost?

A self-contained composting toilet will set you back roughly $600 on average. More complex systems may cost thousands of dollars more. As you can see, they are considerably more expensive than their regular counterparts.

An array or toilet bowls display in store

Can You Flush Regular Toilet Paper?

No special toilet paper is required. These systems can break it down.

In most cases, it can go directly into the toilet. Because paper goods do not dissolve as rapidly as solid garbage, they will remain visible for a long time after the solid waste has decomposed.

Certain types like marine or RV paper will decompose faster than other paper. Single-ply is also preferred since it is easier to break down.

The solids bin should not include diapers, wipes, or tampons. Many of these things are chlorine-bleached and produced from a combination of rayon and non-organic cotton. These will not decompose regardless of how much time they’re given.

Jeffrey Douglas
Jeffrey Douglas own a landscaping company and has been in the business for over 20 years. He loves all things related to lawns or gardens and believes that proper maintenance is the key to preventing problems in the first place.
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