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Composting toilets get the job done, whether you’re off-grid on a boat or cabin, enjoying the freedom of living in a tiny house, or want to upgrade your old water-hog traditional toilet. They use little or no water and don’t require hookup to a sewer system, so they work by letting the natural process of aerobic decomposition occur.
Some are installed permanently with a vent to the outdoors, while others are portable so they’re easier to set up and can be moved to another location if need be. While many people build their own with the "humanure" system (also known as the bucket-and-sawdust method), there are also some great options on the market that offer convenience and less mess.
While there’s no organization that sets functional requirements for these products, some manufacturers seek NSF International certification, an independent organization that verifies consumer products meet basic standards such as being odor-free and able to handle the advertised capacity. Ahead, the best composting toilets available.
This self-contained toilet has stainless steel hardware, a 12-volt-powered built-in fan, and a hose to vent to the outdoors—and it’s made in the USA. The agitator to mix materials has two available options: It’s operated by your foot or moved by either a spider handle or a shifter handle (which moves up and down vertically so it fits in tight spaces). Peat moss or coco coir work best as the bulking material, or substrate, to process waste.
Reviewers rave about the fact that there’s no smell, so it’s ideal in a boat or RV. Many people say the liquids need to be emptied every few days, but the solids can go for months (the company estimates approximately 60 to 80 uses before you’ll need to empty). The toilet was designed by two long-time sailors in 2007, and the company supports charitable organizations such as Unchained Movement, which combats domestic sex trafficking, and Warrior Homesteads, which gives homeless veterans sustainable housing on farmable land.
Because there’s a great deal of variation in how these units work and are installed, make sure to follow the manufacturer’s instructions when setting them up. Most don’t require a ton of carpentry or special skills to install. But in some municipalities, you may need to pull a permit for a permanent installation, so do your homework ahead of time so you’re aware of local regulations.
This toilet has been made in Sweden since 1976 and happens to be the brand Treehugger founder Graham Hill has in his Maui home. The Separett separates urine and solid waste in order to reduce smell and the volume that must be handled. When you sit down, a screen covers the solid waste container and rotates it at the same time so contents are distributed evenly. There’s also a child seat that can be purchased and attached to the seat for little ones.
It comes with a fan that has AC/DC adaptors. You can use a biodegradable bag (set in the container) to simplify cleaning. There’s no need to add bulking material, so reviewers say it looks and “feels” more like a regular toilet. The company supports projects to provide better sanitation to people in China and Peru.
Composting toilets are not maintenance-free, so follow your manufacturer’s recommendations to keep everything running well and odor-free. Finally, remind all guests that they must be seated during use; otherwise, units won’t properly separate liquids and solids, which helps prevent odors.
If you’re looking for a medium-capacity toilet, this low-profile unit is compact and easier on your wallet than many other models. It plugs into a regular 110-volt outlet and is designed for seasonal use for up to three adults or for one adult for residential use. Use the handle to mix and aerate the materials in the three-chambered holding drum every other day the unit is used. You’ll also need to add a cup of bulking material per person per day. Reviewers say the customer service isn’t the greatest, but that it’s easy to install and eliminates hassling with septic issues in rural areas.
Read Next: The Best Outdoor Compost Tumblers
If you need a simple, economical solution for your off-grid camp, this low-tech option is the answer. It requires no electricity, no water, no plumbing, no venting, and no chemicals. Basically, it’s a bucket inside a wooden box with the toilet seat attached. You’ll add sawdust to cover the waste after each use. When the container is full, you can add the contents to your outdoor compost bin or pile. The simple concept of this product has been promoted for years by Joe Jenkins, an advocate of humanure.
This closed-system toilet, made in Sweden, breaks down waste materials in the toilet itself. It’s pricey, yes, but it’s completely automatic: Sitting down opens the trap doors, and closing the lid activates the mixing arm to break down paper and distribute moisture in the upper chamber. A fan recirculates warm area underneath the compost. A float switch kicks up the heat if excess liquid is detected.
The dry material drops down into the lower chamber, where an LED light indicates when you need to empty it. The only additional expense is a compost mix, which must be added to the toilet to boost the process. Reviewers say it’s worth the price if you’re at all squeamish about maintaining other types—plus, it’s designed for families of four for full-time use and six for part-time use.
Envirolet is another popular composting toilet, which Treehugger Design Editor Lloyd Alter owns. This all-in-one design features a wide box for air circulation around the compost. The unit, which is made in Canada, has dual fans to create a large volume of airflow at a high rate and a heater to evaporate liquids. You won’t have to crank anything to mix the contents, so it’s more hands-off than some systems. Its large capacity means it’s a good choice for families or those who get a lot of visitors. It can accommodate up to eight people per day for vacation use or six people per day for continuous use.