Eco-friendly living is all the rage now, and people are constantly looking for ways of making their homes more sustainable.

One of the ways of doing it is installing the composting toilet. This toilet, also known as waterless, composts solid waste using a medium, so you can dispose of it in the soil or even use it as a fertilizer!

If this caught your attention, scroll right below, and you will find the best composting toilets and a comprehensive buying guide that will help you choose a unit for your needs.

Quick Picks

How Does a Composting Toilet Work?

A toilet that doesn’t use water? You must be joking!

No, it’s a fact:

The decomposition process doesn’t require water, only a carbon-rich medium — such as peat, coco coir, tree bark, or leaves — and some oxygen, so the aerobic bacteria can do their job. 

The key to a quick and proper decomposition process is maintaining the balance between carbon and nitrogen, ensuring optimal aeration, humidity, and temperature settings. And your toilet is pretty much equipped with all the necessities for it:

• Fan. Modern composting toilets have a built-in fan that, along with removing gasses and residual odors, supplements the bacteria with oxygen and reduces excess moisture. Solid human waste contains water, which is enough for the bacteria to grow, but too much moisture can drown it, so the fan ensures air circulation inside the compost bin and prevents that from happening.
• Urine diverter or urine bottle. Mixing solid and liquid waste stops the decomposition process because urine contains too much nitrogen and can disrupt the microbiome. That’s why modern toilets either have a separate container for the liquid waste or can be connected to the drainpipe to remove the urine.
• Mixers. To facilitate the decomposition process, waste should be thoroughly mixed with a composting agent, To do this without getting inside a compost bin, modern toilets have a crank or a spider handle, which incorporates the medium particles into the waste. Also, the handle serves as an indicator for cleaning: when you feel like it’s become hard to move, then it’s probably time to empty the toilet.

And there you have it!

The final product of decomposition is a humus-like substance that smells like damp soil. Most states require you to dispose of it with the licensed septic hauler in your area. But in states, where the soil amendment is permitted, you can use this humus as a fertilizer for non-edible plants in your garden (1).

What Makes the Best Composting Toilet?

Dimensions

Most composting toilets don’t differ from your regular commode in dimensions. The only major difference is the agitator handle that can extend to the side and requires some extra space to accommodate it.

Also, some dry composting toilets, such as those made by Nature’s Head, have an extra high bowl (20-21’’). This falls beyond the Americans with Disabilities Act (ADA) but can still be comfortable for those who have bad knees or are taller than 6 feet.

Tanks Capacity

The size of the toilet’s compost bin and the urine bottle — in case if your commode doesn’t have a urine-diverting system — will define how often you will have to empty it. 

Generally, the urine bottle needs to be emptied every 2 to 5 days depending on the use. The solid waste bin will last you from 1.5 to 6 months which also depends on the following factors:

• Frequency of use. An average adult needs to use a toilet 1-2 times per day to do a Number Two. The regular composting toilet can hold up to 60-80 uses for a solid tank which means that it may last you 1.5-2 months. If you live with someone, the time will proportionally decrease for 3-6 weeks for two adults, 2-4 weeks for three adults, etc.
• Location. If you purchase a composting toilet for a remote cabin that is inhabited for 2-3 months per year, your toilet will last significantly longer. Moreover, you can even leave the waste to fully compost when the cabin is not in use.

Power Source

The built-in fan in the composting toilet needs electricity to run, either a battery or a socket. Battery-operated toilets are more suitable for off-grid locations, RVs, and other places where connection to a socket is limited. On the other hand, plug-in toilets are more reliable and long-lasting. Don’t worry, it doesn’t use that much energy, and the fan is shutting down automatically.

Ease of Emptying

Finally, a composting toilet can get quite heavy as the solid waste bin fills up. So it should have a convenient design that allows to empty it single-handedly. Modern composting toilets usually have a detachable solid waste tank that can be emptied and hauled away, or come with several interchangeable bins, which allows you to let the waste decompose entirely for several months.

Tips for Maintaining a Composting Toilet

A composting toilet is pretty different from your regular commode, and it needs to be maintained differently as well. Here are some recommendations on how to care for the composting toilet so that it will serve you for years:

• Sit on the toilet while you do your job. Yes, even if you’re a male. Peeing in the sitting position reduces the chances of urine entering into a solid waste chamber, resulting in an unpleasant sewage odor. 
• Turn the agitator every time you use the toilet. This will help break the waste and composting agent mixture into smaller chunks and aerates it, promoting bacteria growth and facilitating decomposition.
• Don’t put toilet paper or other hygiene products into the bin. Toilet paper will significantly slow down the composting process and may make you empty the toilet more frequently. Hygiene products that contain plastic and synthetic materials don’t compost at all, so you need to utilize them separately.
• Monitor liquid and solid bins. Make sure you empty the urine bottle regularly to prevent overflowing and bad odors. Also, monitor the compost bin’s state: if the agitator handle feels challenging to move, it’s time to empty the bin.
• Do not add liquid into the solids bin. The composting agent should be moist but maintain a crumbly structure. Usually, water contents in the human waste are sufficient to keep it moist, but if you think that the mixture feels too dry, you may spray some water on it.
• Do not use regular soil as a composting agent. Aside from composting agents, regular soil may contain pathogen microorganisms as well as insects or worms. These definitely aren’t things you want inside your toilet.
• Maintain proper nitrogen-carbon ratio with additives. Good compost needs a nitrogen-carbon ratio of about 1:30 (2). Human waste contains a high amount of nitrogen compounds, so you need to add carbon-rich agents, such as sawdust, wood chips, or bark to balance them and help compost bacteria to thrive.