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What is a Composting Toilet and How Does It Work

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When you are considering being more eco-friendly and saving water, chances are a composting toilet might have come up in conversation. These toilets can be a wonderful tool to help the environment while simultaneously saving on that ever-growing water bill. Before moving forward, it is important you learn how a composting toilet works, and what exactly it is.

Once you better understand how a composting toilet works, then are you able to see if this great way to recycle your waste and limit water consumption is a fit for your home.

​What is a Composting Toilet?

​First of all, it is not anything like those terrifying fairground ​port-a potties that we have all regretted having to use at one time or another. This more sophisticated and smell free system uses multiple working parts to ensure that you are not smelling anything foul or attracting bugs.

A composting toilet allows you to not just flush away your waste to a septic tank. Instead your waste will be broken down inside of the housing unit, allowing you to limit the waste you put out into the environment and then in turn use it as a fertilizer for your non edible plants and trees.

A porcelain toilet in the bathroom

How Does a Composting Toilet Work?

​To know more about composting toilets, it is important to know how does a composting toilet work. Knowing how it works will help you to understand not only why a composting toilet is excellent for helping out the environment, but also to see if this type of toilet could fit into your home.

​The Basics of a Toilet that Composts

​A composting toilet looks and feels like a standard toilet that you are familiar with. When you use it there is a flush latch that will open, similar to those that you see in a camper or RV. These toilets can function without water or offer a low flush option that uses about a pint of water with every flush.

Composting toilets are good for the environment, and highly convenient for smaller spaces. A lot of people install them in the RV’s for their convenience, or their homes for their eco-friendly components.

​Separating the Waste

​In order for the composting to work properly, the liquids and solids must be kept separate. This means that your urine, will be drained down into a separate cup or container, while the more solid waste will be dropped into the main composting bin.

Inside of the composting bin you can choose from a few different fillings that will help with the compost breakdown inside of the toilet.

Some popular compost fillings include:

  • ​Saw dust
  • ​Peat
  • ​Coconut fiber

​Types of Compost Toilets

​There are mainly two types of composting toilets. A simpler version is an all in one housing unit that stores your waste inside of the toilet. There is usually a hand crank on the side that you will use to mix the solid waste with the interior filling to make sure that it is composting properly.

This is a great starter option for having a composting toilet in your home. Since it is a little more all in one contained, this is not a great option for a large family household. It would be better suited in a small home with 1-2 people or at a vacation home.

There is also a more advanced unit that will flush your waste down and away from the toilet to a separate composting bin. You can link up multiple composting toilets to the one bin via a series of plumbing pipes that will transport your waste away from the toilet. Think of it as multiple shower jets ​as good as​ a top rated rain shower head in a spa​​.

This type of composting toilet is better for a multiple person household, since it will transport all of the collected waste to a larger composting bin that will not need to be emptied as frequently.

​Composting Toilet Odor Control

​Especially in the simpler models, odor can be a huge worry when you don’t know a lot about composting toilets. If your waste is just sitting under the toilet’s main housing, then how can it not have a potential odor problem.

The truth of the matter is that there is no odor that will come up from this type of toilet. Composting toilets were created with multiple mechanisms to ensure that you are not smelling the aftermath once you flush.

Man holding his nose because of something smelly
​Source: huffingtonpost.com

Flush Latch

​The first major defense in keeping odors out is a flush latch. This closing hatch door traps the waste down inside of the composting bin and does not allow odors to escape.

It also acts as a separation barrier so that every time you go to use your composting toilet, you aren’t looking down at an open waste bin like you see in some port-a potties.

This way you have a clean, fresh smelling toilet every time that you go to use it.

​Exhaust Fan

​Composting toilets also have an electrical need. You will either need to plug them in like a vacuum or install batteries into your composting toilet for the inner exhaust fan. This fan keeps the air circulating so that the odor isn’t just sitting.

​Compost Filling

​The compost filling is what goes into the main solid waste tank of your composting toilet. You can use a variety of fillings for your composting toilet, there isn’t really one that outshines the rest. It is more of what you can find available in your area or if you have a preference.

The compost filling needs to be enough to cover your waste, if you find you are having an odor creep up from your composting toilet then there is probably not enough compost filling to cover and begin the breakdown.

​How to Use a Composting Toilet

​Using a composting toilet is pretty much the same as using a regular toilet. The main difference you will notice is that you are not having a pool of water sitting in the bottom.

Most composting toilets use a low water flush method that uses a pint or less of water to help move the waste after you have finished.

This also adds the needed moisture into the solid tank and helps dilute the separate urine tank.

​Can You Use Toilet Paper for Composting Toilet?

​This might be the second biggest concern, next to odor control. How does toilet paper fit into the composting process and will you be able to use it and flush it once you have finished.

The simple answer is yes, you can use toilet paper with a compost toilet. Some brands that offer a thinner or simpler toilet paper would be best, but you can use what you readily have available.

toilet paper hanging on a handle in the bathroom

Also, you will want to try to use less toilet paper than you normally would with a regular toilet. This will keep your composting toilet from filling up too quickly.

​Common Compositing Toilet Problems

​A composting toilet is pretty low maintenance as long as you make sure it is working properly.

If you do notice a lingering odor, then make sure that the latch door is completely closed. You will also want to check and make sure that the unit’s exhaust fan is plugged in and still running.

You should not be encountering any overflows as long as you know your schedule for emptying it.

​How Often to Empty a Composting Toilet

​When it comes to owning and using a composting toilet, there will come a time that you will need to empty it. Different factors will adjust this time so let’s take a look at how often you may need to empty it. Here are several questions to ask yourself to make the determination:

​What’s Going to Be Inside the Composting Toilet?

​When you first prepped your composting toilet, you added a filling such as sawdust or coconut fibers inside. This filling will cover and coat the waste that comes down into the main chamber.

Once your waste comes into contact with the composting material, it will begin to break down and not be just waste lying there, instead it will loose it’s shape and any pathogens or harmful bacteria will be greatly reduced.

Close up of a composting toilet with a bag of filling beside it

Before you open the composting chamber, you will want to give any hand cranks a few turns, just to make sure that everything is well mixed together. This will also help eliminate some clumping that could be present in the mix as well as loosen the compost and make it ready to be dumped.

How Often Will You Need to Empty the Waste?

​Since there are two types of composting toilets this question can be broken down into two separate emptying answers. For the simpler all in one housing models you will be emptying it multiple times a year. The larger models that have lines to draw the waste away from the toilet and down to a large bin will only need to be ​cleaned out once every year.

You will also need to factor in:

  • ​How many people use this toilet?
  • ​How often is the toilet used during a month?

The increase in individuals using a single toilet and how many days out of the month it is being used will increase how often you will need to empty it. On average a simple composting toilet can function well for 1-2 people.

If your composting toilet is in a home that isn’t used daily then you can go longer stretched between emptying it. Not to worry if you are away from your toilet for awhile, this just gives your waste more time to break down when it is not in use.

​How to Empty a Composting Toilet

​You will want to make sure that you are wearing the proper protection before you open the composting toilet waste compartment. While it is broken down, you are still dealing with waste so you want to protect your skin and protect your eyes from any tiny filling particles that might get kicked up such as sawdust.

Once you are properly equipped you will want to make sure that you have everything you need to dump the waste. For simpler models you should be able to lift and dump the housing chambers without too much trouble.

For the larger composting toilet systems that have a separate and larger tank, you will need a shovel and a bucket or wheelbarrow to put the waste into and then transport it.

Start with the urine chamber. This will be an easy dump, since the waste you are dealing with is liquid and can be easily poured out. Next you will want to access and clear out the larger compost chambers.

​What to do with Composting Toilet Waste

​There are a few different ways that you can dump the composting toilet waste. Depending on where you are located, you may need to check the local dumping laws just to make sure that you are in accordance, especially if you are on public property or live in a complex.

Man hold up freshly ground composte

Bag the Waste

​Due to landfill rules, human waste is allowed to be dumped. While this can seem counterproductive to the composting lifestyle, if all else fails you are able to place your solid composted waste into a trash bag and send it to the dumpster.

There are also specialized bags that are made to compost that you can use. Just don’t let it sit, because the bag has a short lifespan once you begin using it.

​Bury the Waste

​The most common way to empty a composting toilet is to bury the waste. You will want to pick a spot away from any edible vegetables growing and dig a hole that will allow at least 4 inches to be covered with dirt on the top.

You will then dump your waste in it and cover the pile up with dirt. This will allow your composted material even more time to complete breaking down and completely eliminate any remaining pathogens that can live in your stool.

It is important not to allow your freshly composted waste come into contact with any edible plants since there is a risk of contamination or disease that can spread from the compost into the edible parts and make you sick.

You can however freely use this compost on non-edible plants and trees. Your liquid waste that you are dumping follows the same no edible plants guidelines. A common dumping area for your liquid waste is around the roots of a tree or plants since your urine can give valuable nutrients to help plants grow.

Knowing where to empty a composting toilet will take some of the cleaning stress off of your mind. Get better in touch with your outdoor plants to find out which ones would benefit from your composting.

How to Clean a Composting Toilet

​Since you are dealing with organic matter, you will want to keep your cleaning as organic as possible so that you don’t disrupt the composting process. This means skip the bleach and use vinegar instead.

White vinegar is great at cleaning and sanitizing various surfaces due to it’s highly acidic content. It is also safe to use on and inside of a composting toilet. You can simply spray the bowl down with vinegar and give it a quick wipe if you see anything that needs to be cleaned.

A woman in yellow gloves using an orange rag to clean a toilet

Since composting toilets use a low water or no water flushing system, you will be surprised to find that it won’t need as much cleaning as a regular toilet demands due to water streaks and rings.

How to Install a Composting Toilet

​Now that you know the ins and outs of how does a composting toilet work and how to use one, you can go forward with trying one out and learn how to install a composting toilet.

​Simple Composting Toilet

​Installing an all in one housing unit type of composting toilet is a mostly easy task. It’s as easy as installing a top quality handheld shower head. The only obstacle you will face is when it comes to installing the intake line through the wall and an exhaust fan through the ceiling.

It can be done by the average DIYer as a home improvement project but you may want to consult a specialist at your local ​store for a few tips before you take on the install. This can help you prepare for any issues that may arise while you are installing.

​Separate Housing Composting Toilet

​For the more advanced septic like systems in these composting toilets you may need to consult a plumber or a general contractor. This is mainly because you will be running pipes down from the composting toilet and leading your waste to a further away separate container.

This process can get complicated depending on how far your pipes will run and how many toilets you have linking to the compost barrel. Using a professional’s opinion will help you make sure that the composting system remains sealed and does not leak any odors or attract flies.

Composting toilets are not just for cabins in the woods or an RV – you can install and begin using a composting toilet in your home today to help preserve your water intake and become a more eco-friendly and sustainable home.

Separate housing for toilet in the woods


When it comes to figuring out how does a composting toilet work, it is vital to learn more about the full process. A composting toilet is nothing like a stereotypical portable bathroom, instead it is a step in a greener and more eco friendly direction.

Lauren Moldvay is a freelance writer from Virginia and the mother of one (not always) sweet little girl. She specializes in trying to help others find easier ways to clean, manage the home and save money with DIY projects.