What Is a Composting Toilet? (And Should You Get One?)

Disposing of human waste in creative ways is becoming more and more necessary over time. Enter the composting toilet, which is both energy and water-efficient. This makes it popular among travelers, environmentalists, off-grid dwellers, and farmers. But what exactly is a composting toilet, and how does it work?

A composting toilet is a “dry” alternative to traditional flush toilets that convert solid waste to compost. Solid waste is usually combined with an organic medium, like sawdust or peat, to expedite the composting process. Most composting toilets are all-inclusive units with very low maintenance.

Now, let’s explore the details in depth so you can decide if installing one might be a viable option for you.


How a Composting Toilet Works

There are two main variations of composting toilets:

  1. DIY composting toilets are often made in lieu of traditional outhouses. They employ a large drum filled with a composting agent covered by a conventional toilet or seat. As the barrel fills, more comping medium is added, and the mixture is turned. It takes a long time for the container to fill.
  2. Commercial composting toilets are self-contained all-in-one toilets that have a smaller load capacity and need to be changed more often, but their claim to fame is their low-profile and traditional look. They tend to be a bit more on the pricey side when compared to homemade set-ups, but you’re paying for convenience and reliability. Here is a really good model that I recommend, found on Amazon.

Composting toilets require no water, and thus no plumbing connection is needed to convert solid waste into compostable material. Most composting toilets have a diversion tank to separate liquid waste from solid waste.

Solid waste is held in a compartment with composting material such as coconut coir (processed husks), sawdust, and sphagnum peat moss. This compartment typically has an agitator bar that allows the users to mix the composting medium with the waste. DIY composting toilets often need to be stirred or agitated manually with a pitchfork or shovel.

Healthy bacteria break down the waste and medium mixture over time and creates fresh compost that can be used for your next gardening project. Some composting toilets have large receptacles for waste, while others accommodate several weeks’ worth of solid waste at a time.

Smaller composting toilets can be emptied every few weeks, and the mixture can be bagged and stored for use later, or you can add your mix to your compost pile or pit.

Good, rich, healthy compost takes 6 to 12 months to mature. Most composting toilets don’t create compost on their own. Instead, they convert human waste into pre-compost. Larger composting toilets are capable of converting waste to compost in a self-contained manner.

Commercial composting toilets have a urine diversion tank. Composting toilets that are built-in 55-gallon drums that you may see in outhouses or on farms typically don’t have a diversion tank, but you can find schematics to include one if you really like.

How Long Does a Composting Toilet Take to Work?

Composting, as we discussed before, is a long process. It takes six months to a year to develop a compost fit for your garden. Composting toilets typically can hold 40 to 60 waste excretions in their solid tank. This equates to 2 to 3 weeks before it needs to be emptied.

Because compost takes so long to develop, people that have composting toilets in motor homes or RVs sometimes struggle to utilize their compost for the intended purpose. It’s hard to store bags of solid human waste long enough for them to be viable if you are living or traveling in an RV full-time. Part-time nomads, though, struggle less with this issue.

Composting takes patience. Fortunately, if you already have a compost pile, the compost that these toilets create is an excellent source of nitrogen. There are two types of compost. Green, is rich in organic materials like food scraps and, in this case, human waste. The other variety is brown, which is things like sawdust, dried leaves, and lawn clippings.

Composting toilets create a perfect balance between these two types of compost materials. Waste is so high in nitrogen that it actually speeds up the composting process. Most compost takes about a year to fully mature, but people that have composting toilets report that this nutrient-rich compost source often speeds up the process by a couple of months.

Why Use Composting Toilets?

There are many reasons why someone might choose to use a composting toilet. Most people that seek these toilets out install them in non-standard living quarters such as motor homes, tiny homes, off-grid homes, or for workshops and farm purposes that aren’t easily connected to plumbing and running water.

There are environmental reasons to use composting toilets as well. They don’t use water. Conservation of resources will continue to be a pressing issue as the world looks at innovative ways to combat complex resource scarcity issues.

Composting is also great for your garden and fertilizing your own plants. Commercial compost is pretty expensive, and that price tag only increases depending on the size of your operation. Recycling waste and putting it to good use is not only environmentally friendly but also economically responsible.

By using a septic tank system, composting toilets can eliminate the need for costly tank maintenance. Septic tanks need to be professionally emptied, but composting toilets are quickly emptied and processed by the user.

Do Composting Toilets Smell Bad?

If you’ve ever used a porta-potty, you likely have been greeted with a noxious wave of methane and ammonia. Maybe you’re afraid that a composting toilet will suffer from the same drawback. Fortunately, composting toilets have figured out how to solve the problem of smell.

Most composting toilets on the market have built-in fans and external ventilation. As long as you separate your solid and liquid waste, you probably won’t have too many smells. Properly maintained, they are mostly smellless.

It would be dishonest to suggest that they have zero smell. No toilet is entirely odorless. When the lid is open, there will be a bit of a smell, but the ventilation fan will push most noxious smells out. If your composting toilet is in a vehicle, some folks have expressed minor odor when they are in transit at high rates of speed or on rough dirt roads.

DIY composting toilets that are more in the vein of composting outhouses might have more smell, especially if the tank gets emptied less often. Proper ventilation, however, can get this odor down to a minimum.

Do You Have to Empty a Composting Toilet?

Composting toilets do need to be emptied. Large DIY drum-style composting toilets may not need to be emptied for several months or longer. Smaller commercial composting toilets need to be emptied every couple of weeks.

To empty your composting toilet, you need to dump your solids into a large trash bag or by emptying directly into your compost pile. Smaller composting toilets are easier to empty. Most involve removing the lid, and unclipping the tank from the base allowing you to dump it by hand.

Large composting toilets that use a large drum or barrel will require a bit more manpower to empty. Waste piles up and becomes quite substantial over time. A full composting drum may need a couple of extra hands to empty. Despite being harder to empty, they require substantially less maintenance over time.

The liquid tank from composting toilets that have diversion tanks needs to be emptied every few days. Most liquid tanks hold only a couple of gallons at a time. The liquid reservoir can be emptied at a public restroom or an RV dump if you are on the road. You can ideally empty it wherever it won’t pose a significant problem.

Can You Pee in a Composting Toilet?

The short answer to this question is yes. You can urinate in a composting toilet that has a liquid diversion tank. The important thing is that you never pee into the solid waste tank. The addition of a liquid to the solids will create cleanliness problems.

Peeing in the solid tank will create quite a bit of smell. Urine is compostable, however, and speeds up the composting process. Urine can be a great way to start a compost pile since it is high in nitrogen. But seeing that most composting toilets are in small spaces like RVs or tiny houses, you want to make sure you don’t combine your waste.

When urine and feces mix in the solid tank, it creates a sludgy mixture that is difficult to dispose of and is more likely to attract unwanted pests. You want to limit the moisture level of your solid waste to the best of your ability. Mistakes do happen sometimes.

As it turns out, it’s pretty difficult for many people to not #1 when taking a #2. If this happens to you, you can add a few extra scoops to your composting medium to counteract the moisture level. The same principles go for diarrhea, vomit, or menstrual blood.

What About Toilet Paper?

Toilet paper, like brown paper bags, is biodegradable and compostable. You can toss your TP into the solid tank, and it won’t cause any trouble. Toilet paper does break down substantially slower than solid waste, so you’ll likely still see it long after your other waste has broken down.

On a side note, toilet paper rolls are also compostable. Marine or RV toilet paper, like this kind, is thinner and breaks down quicker than TP designed for the home.

Some people that use their compost to enrich their soil try to limit the amount of bleached paper that goes into their mix. You can always keep a separate container next to your composting toilet to handle toilet paper if you don’t want to compost it. Several companies manufacture non-bleached toilet paper as well.

Is a Composting Toilet Illegal in Any States?

Many states require that you have a traditional toilet that employs the use of the public sewer system or private septic tanks to meet building codes and regulations. Massachusetts, Arkansas, Florida, Colorado, Idaho, Pennsylvania, Tennessee, Illinois, South Carolina, Oregon, and Maine all have laws that allow the use of composting toilets in place of a traditional toilets.

Other states allow the use of composting toilets, but you’ll need to have access to running pipes or a septic system somewhere on your property. Other jurisdictions require you to get a license in order to have a composting toilet on site. If you are looking into getting one, its best to do your research and brush up on their legality in your area.

Other Things You Need to Know

There is a bit of debate in the composting world about whether human waste is okay to use for agricultural use. Some people are very opposed to using human feces for edible plant life. There is concern that waste products may carry disease or may introduce non-organic toxins to your soil. Think of food preservatives and medications. If you are using compost for your own personal garden that you’re not taking to market, it shouldn’t pose much of a problem. But it’s worth noting that most people don’t want human manure fertilizing their food sources.

Owning a composting toilet runs the risk of occasional insect infestation. Gnats and no-see-ums can occasionally make themselves at home in your toilet. If this happens to you, you’ll need to take apart your toilet and thoroughly clean it with bleach, vinegar or boiling water. Fortunately, it is an uncommon problem to encounter as long as you keep up with regular maintenance and waste removal.

Composting requires heat. Composting won’t happen unless the solid tank is at least 55° Fahrenheit (13° C). If you live in a cold climate and your composting toilet is outside, you’ll need to install a heater or move it indoors.

There is a common myth that composting toilets are unhygienic or pathogenic. As long as you properly maintain your composting toilet, it’s significantly more hygienic than a traditional flushing toilet. The type of bacteria that forms is not harmful to you as long as you properly handle it with care and keep your solid and liquid wastes separate.

If you have a pet, you can compost their waste as well. Simply bag up their waste when you go for your walks and empty your doggie bags straight into the solids tank. Composting can actually be fun for the entire family. Not even fido needs to be excluded.

Final Thoughts

Overall, composting toilets are an environmental solution that makes a lot of send for many different types of people. In fact, it’s becoming more of a rule than an exception for people living in tiny homes or living an off-grid lifestyle. The great thing is that it is perfectly compatible with building a sustainable lifestyle. I highly recommend looking into one if this is a good match for you.

Helpful Recommended Products

For your convenience, here are the products mentioned in this article that I recommend:

For more, don’t miss Is Your Compost Too Hot or Dry? (Here’s How to Check).

Anne James

Hi, I'm Anne but my grandchildren call me Jelly Grandma. I have over 50 years of experience as a Southern cook and am a retired librarian. I love sharing what I have learned. You can find me on YouTube as well! Just click the link at the bottom of your page.

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