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Composting Toilet: What Is It? And Which Are The Best? 

Sustainable Home

Last Updated on May 8, 2024

If you’ve ever been out camping, chances are you’ve heard of a composting toilet before. But how does a composting toilet work?

Unlike flushable toilets connected to plumbing and the sewage system, compost toilets collect human waste for, well, compost. A compostable potty system is ideal for off-grid and tiny home living, but you can also utilize them in boats, RVs, and cabins. They use little to no water and don’t require hookup to a sewage system, making installation easier. So how does a composting toilet work? Is it right for your situation? Read on for everything you need to know.

A composting toilet in the woods with overlay text reading "what is a compost toilet?"
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compostable potty system

Depending on the compost toilet you choose, some are portable whereas others can be installed permanently with a vent to the outdoors.

However, don’t let the name “compost toilet” fool you — this mechanism will only separate and collect your waste. You still have to put in the work to actually compost it if that’s your end goal (more on that in a bit).

Intrigued? Here’s everything you need to know about this type of toilet and where to get the best ones.

what are they and how does a composting toilet work? 

How does a composting toilet work, you ask? A compost toilet is a type of dry toilet that makes composting human waste easier. Composting is carried out by microorganisms (mainly bacteria and fungi) under controlled aerobic conditions. 

This dry toilet uses little to no water. Instead, it mixes human waste with peat moss, sawdust, or coconut coir. Typically, these dry materials are added in before and after going to the bathroom. 

Aerobic bacteria break down the materials, feces, and urine in much the same way as a compost heap, just in a closed container.  

A compost toilet system starts the composting process, but doesn’t entirely finish it (temperatures don’t get high enough for this to typically happen). In order to ensure your feces turn into compost, you must have another compost bin set up specifically for this purpose (more on that later). 

There are two kinds of composting toilets:  

  • Self-contained composting toilet: These are often used in RVs, boats, or cabins. The smallest of them are portable. Others can be fitted in where normal plumbing is difficult, like basements, garages, or guest accommodations. They are typically fitted with a vent to expel any gases that build up. Liquids may be contained but are often drained away, while solids are composted in a removable container. These are the most popular options.
  • Central system composting toilet: Sometimes called split systems, these are very similar to standard toilets that hook up to a septic tank. The tank needs to remain warm for composting to be effective, so it’s impractical to install outside. They don’t require a continuous electricity supply, making them a good fit for off-grid locations.  

Which composting toilet you get will depend on your specific situation, needs, and budget. I highly recommend getting a composting toilet that separates your urine and feces if you intend on composting it. 

How does a composting toilet work? A compostable potty with a bucket of sawdust next to it.

can you poop in a composting toilet? 

Yes, you can poop in a compost toilet. Just be mindful that if you want your poop to break down and turn into nutrient-rich compost, there are some additional steps you must take. 

First, it’s easier to compost your feces with a urine diverting compost toilet (one that keeps them separately, essentially). Urine mixed with feces will be too wet for efficient composting and would create conditions that allow smelly bacteria to flourish.  

Once you have the human waste, place it in a dedicated composter. The type of container you use is important: It must not leach out the bottom or sides, as this may contaminate groundwater. And it must be protected from rain and snow since it cannot get wet.  

Having good ventilation is key. The best way to ensure this is through a rotating compost drum or barrel that sits off the ground. Many hardware stores carry this. 

Adding leaves or grass to the compost bin with human waste is okay, but don’t add too much vegetable waste as it can make the contents too damp. If it seems too wet, add more dry elements like paper, ripped up cardboard, dry grass, and leaves. It’s okay to add a bit of water or green plants if it’s too dry. 

Ideally, having two compost bins to process human waste is best. Use one at a time — when the first bin is full, start using the second.  

Make sure to never mix composted human waste with edible plants, because there may be a small chance some dangerous bacteria are still present. Non-edible plants, like flowers, are the ideal choice. 

what about urine? 

As for urine, you can just use it as fertilizer by diluting it with some water. It has a lot of nutrients like nitrogen, potassium, and phosphorus that many plants love.  

If you’re on the road and disposing of urine in the wilderness, try to avoid ornamental plants as they may have been recently fertilized or have particular needs. Play it safe and go for bare soil or a patch of weeds.  

Also, make sure to spread urine out in a wide area, rather than pouring it all in one spot. Walking and pouring is a good idea. 

And please make sure you’re at least 200 feet away from waterways to protect the ecosystem. Urine can cause eutrophication (too many nutrients leading to algae blooms) in waterways. 

Photo one type of composting toilets

how often do composting toilets need to be emptied? 

How often you empty a compost toilet will depend on the make and model of your specific compost toilet. But most commercial composting toilets need to be emptied every 2-3 months.  

To empty, most compost toilets have a chamber beneath that has separate liquid and solid waste holding compartments. Check with the manufacturer to see how to remove the tray or waste vessel, but it normally requires releasing a cover or latches. 

You can add your solid waste to a compost heap and have it become compost over time. Just be mindful that human waste in a compost heap must reach certain temperatures for a long enough period to kill off any bacteria. 

Another option is putting it in a compostable bag and adding it to a trash can (if you’re on the road, this may be your best bet).  

Burying is another option, just be mindful that some parks may bar this. But if you’re in the wilderness, dig a cat hole at least 8 inches deep and bury your solid human waste there, as you would if you were camping. 

do compost toilets smell? 

A compost toilet shouldn’t smell bad if you properly maintain it. Follow the manufacturer’s recommendations for maintenance and empty after a few uses to prevent odor. It smells more like wood or mulch if you’re using a toilet that requires you to add dry matter to it. 

do composting toilets need electricity? 

Certain compost toilets don’t need electricity to function, making them great for off-the-grid living. There are both electric and non-electric versions.  

Several models need power for continuous venting with fans. Certain composting toilets do this through the use of batteries or wall plugins.  

6 composting toilets for a greener flush:

These six composting toilets get the Going Zero Waste seal of approval. All of these brands are the best on the market.

Some are portable and affordable, while others are pricy and will need to be installed. But there’s something for everyone!

I’ve gone ahead and highlighted some key features of each brand, but it isn’t an exhaustive list. Be sure to check out their websites for more information.

Natures Head: Compost Toilet: What Is It? And Which Are The Best? 

1. nature’s head

  • Self contained composting toilet 
  • Compatible with RVs, tiny homes, vessels, cabins + homes 
  • 12 volt electric power fan

/ SHOP NATURE’S HEAD


Cuddy by compocloset

2. cuddy by compocloset

  • Portable compost toilet 
  • Small compact footprint  
  • Retracting agitator located in the front so you don’t lose any space at the side 
  • Easy to remove solids bin 

/ SHOP CUDDY BY COMPOCLOSET


Loveable Loo: Compost Toilet: What Is It? And Which Are The Best? 

3. loveable loo

  • Portable self contained composting toilet 
  • Best for off-grid camping 
  • No electricity, water, plumbing, or venting needed 
  • Sawdust for bulking material 

/ SHOP LOVEABLE LOO


Sun-Mar: Compost Toilet: What Is It? And Which Are The Best? 

4. sun-mar

  • Self contained composting toilet 
  • Handle mixes and aerates the materials 
  • Three chamber holding drum 
  • 12 volt electric power fan 

/ SHOP SUN-MAR


Separett: Compost Toilet: What Is It? And Which Are The Best? 

5. separett

  • Separates urine + solid waste 
  • Fan with AC/DC adaptors 
  • No need to add bulking material 
  • Needs compost bags regularly 
  • 5 year guarantee 

/ SHOP SEPARETT


Biolet: Compost Toilet: What Is It? And Which Are The Best? 

6. biolet

  • Self contained composting toilet 
  • Ideal for cabins, hunting camps, off-grid homes 
  • Non-electric, waterless  
  • Separates liquid from solid waste 

/ SHOP BIOLET

faqs about composting toilets

is a composting toilet expensive?

The cost varies pretty extensively from model to model, based on the quality of the toilet and your specific needs. Many people suggest that anything under 2 grand is not a quality toilet worth having if you’re living off grid or in a tiny home. However, you can find options on a budget.

what are the drawbacks of composting feces?

It requires commitment to safely and effectively compost human waste. Failure to maintain your toilet properly or compost the waste properly can lead to a septic pile that smells awful and can make you sick. This problem can be expensive to fix, especially if you’re using your composting toilet in a cabin/tiny home, and also renders your bathroom unusable in the meantime.

If you’re going to opt for a compost system, be sure you’re willing to maintain it according to the manufacturer’s recommendations.

how do you keep your compost toilet clean?

You can lightly spray your bowl with water or wipe it down with a moist paper towel or toilet paper. Just be sure not to use disinfectant wipes because they contain harmful ingredients that can kill your compost — plus they do not break down.

are they allowed everywhere?

Regulations for composting vary by location, so it’s always best to consult with local authorities to clarify their requirements or to obtain necessary permits. Plumbers, engineers, or environmental consultants can also offer tons of insight on what you can and can’t do when installing a compostable potty in your area.

Would you give any of these compost toilets a shot? Let me know in the comments!

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