Easy, Eco-Friendly Finds for Everyone. Shop Brightly!

What Is a Composting Toilet—and How Does It Work?

Curious about what a composting toilet is and how it works? This guide covers everything, including types, cost, and benefits.

Written by
Angelica Pizza

Using the bathroom creates waste in more ways than one. But what if we told you there was a way to turn your waste into compost? Enter: the composting toilet.

A composting toilet does exactly what you think it does: breaks down human waste into compostable material. You may have already swapped out toilet paper for a water-saving bidet. Or maybe you use eco-friendly toilet paper options like bamboo or reusable cloths. But now, you can make your bathroom breaks even more eco-friendly with a composting toilet.

If you've never heard of a composting toilet, and you're not sure how it works, you've come to the right place. Here's everything you need to know about composting toilets and how they can decrease the environmental impact of your bathroom breaks.

What Is a Composting Toilet?

When we flush, many of us don't think about where the waste and water go. Your typical household toilet flushes away waste and sends it to a municipal water treatment system or a personal septic tank to be converted to clean water. This process creates significant water waste each time you flush, and it's not the most environmentally friendly option either.

However, a composting toilet decreases water waste while also converting solid human waste into compost materials. Similar to how we can compost food waste, paper, or other household items, we can compost human waste and turn it into organic material to use as a natural fertilizer.

This is done using a process that combines solid human waste with aerobic bacteria—bacteria from oxygen—and natural, carbon-rich materials.

How Does a Composting Toilet Work?

Composting toilets don't require a connection to water or sewer. And you can essentially use one the same way you would use a regular toilet. However, composting toilets separate liquid waste from solid waste instead of flushing them together. There are two types of composting toilets to consider.

1. Self-Contained System

Self-contained systems are smaller; therefore, they require frequent manual emptying for the liquid compartment. These toilets use carbon-rich materials, such as moss or sawdust, combined with aerobic bacteria to compost solid waste.

The entire process is contained within the toilet. And you don't need to flush, so there's no piping system required. Plus, many models come with a thermostat and moisture detector to help move the composting process along.

These toilets may look a little different from the ones in your bathroom, as they're usually portable and electric. You'll likely find self-contained composting toilets in RVs, boats, or campsites. Some tiny homes or cabins may also feature a composting toilet.

2. Central or Split System

Central systems operate similar to how your typical toilet does, using a piping system. The waste gets sent to a composter located nearby, instead of a septic tank. This is often used for systems with multiple toilets or large homes. And with a central system, frequent emptying isn't required. Instead, you let the composting process happen naturally.

Similar to how self-contained systems compost, central systems mix waste with sawdust or peat moss and allow proper air ventilation to eliminate odor and compost waste.

Why Composting Toilets Are Eco-Friendly

According to the Environmental Protection Agency (EPA), toilets make up about 30% of the average home's water consumption, with some older toilets using six gallons of water per flush.

While this figure has been reduced to about 1.3 gallons per flush with recent advancements, it's true that flushing the toilet wastes a significant amount of water. Plus, we usually flush multiple times a day, and it can be unsanitary not to.

Flushing the toilet also means your waste is sent to sewage systems or septic tanks. This could lead to a new set of problems including clogging, hydraulic failures, water contamination, and other malfunctions. However, using a composting toilet eliminates water waste completely, thus decreasing your overall water footprint.

Not only are you saving water, but you're also creating natural compost that can replace the need for toxic fertilizers. Compost adds nutrients to the soil, reduces carbon emissions, and mitigates the impact of droughts—all while eliminating possible pollutants!

How to Get Started With a Composting Toilet

If you're interested in purchasing a self-contained composting toilet, you're in luck! These toilets can be purchased at Home Depot, Lowe's, and even on Amazon.

The average self-contained composting toilet costs around $600, but you can find options as low as $50. Installing a central system is more costly, ranging anywhere from $2,500 to $5,000. And while both systems can be a costly expense compared to traditional toilets, composting toilets are less expensive to operate and maintain.

According to American Home Shield, installing a septic system can cost you up to 75% more than a composting toilet. Plus, because a composting toilet doesn't require water to flush, you'll see a major decrease in your water bill.

So if you're looking to buy a composting toilet, you might have to spend a little more in the beginning. But the cost may offset itself the longer you have your composting toilet, and they may be most useful if you live in a cabin, tiny home, or spend a lot of time on the road in an RV or camper.