With the increased popularity of tiny homes and living off the grid, composting toilets are becoming more popular in recent years. Even those who live with indoor plumbing are opting to switch to using central or self-contained composting toilets. The idea of recycling even your bodily waste makes it the ultimate switch for those who want to give zero waste, sustainable, and self-sufficient lifestyles a shot.
If you’re researching one, we’ve come up with this comprehensive guide that can help you weigh your options and see for yourself which kind and product will suit you best.
At my parent’s remote cabin in northern Minnesota, over the years we’ve tried several composting toilets. Starting with a simple “bucket” style toilet on a 5-gallon bucket. We later upgraded to a Sun-Mar composting toilet and just recently, after 25 years, replaced it with this Nature’s Head Composting Toilet. The cabin is off the grid, too remote for running water and the ground is too rocky (glacial limestone ledge rock) to dig a septic system.
But that’s not the only quality option on the market, continue reading below to see detailed reviews for all the composting toilets we reviewed.
Best Composting Toilets
Nature’s Head Self Contained Composting Toilet ( Spider Handle Design)
Self-contained composting toilets might seem like they’re glorified dump buckets, but this isn’t the case. This Nature’s Head toilet will clearly tell you that this type of composting toilet can look a lot like a regular commode so you won’t have to feel weird or be uncomfortable in using it.
Equipped with a full-sized elongated seat for your comfort, you won’t feel any different while sitting on this throne. Its detachable base serves as its very own composting tank with a urine bottle at the front to effectively separate liquid and solid wastes.
It also has a vent pipe with a small fan powered by a 12V battery to ensure an ample oxygen supply to the accumulated waste and encourage degradation.
This will ensure proper waste decomposition and effective odor elimination. Scroll down to compare to standard crank model by Nature’s Best.
Designed and made by sailors, you can also count on this product to be very durable.
- Made in the USA
- Comfortable seat
- Urine separating
- Easy to maintain
- Requires emptying after 80 uses
- One of the most expensive composting toilets on the market
Sun-Mar Excel Composting Toilet
To provide a fantastic alternative, Sun-Mar has created the Excel Non-Electric Self-Contained Composting Toilet
This product performs just as well as other composting toilets on the market today without the need for a battery. Without an airing and heating device, it’s designed to function just like a chimney.
With a vent that is supposed to be installed vertically and extend up to 2’ to 3’ above the highest point of your roof, it mimics a chimney’s engineering. However, should you need to add a curve to the vent pipe, you’ll need to add an optional 12V fan.
Designed with your comfort in mind, the seat has a good height so you don’t have to sit too low to the ground. It even comes with an attached footstool for small users. You also won’t have to struggle in emptying and cleaning this unit as the compost tray is easily accessible.
- Large capacity
- Non-electric so no need to worry about powering it up
- ½” drain to prevent overflow
- Very easy to use
- Lasts for years
Price can get quite prohibitive
Nature’s Head Dry Composting Toilet (Standard Crank Handle)
If you want to prioritize convenience in your composting toilet, Nature’s Head Dry Composting Toilet is a product you should consider.
Made for application where water access can be limited, this composting toilet is not only eco-friendly, but also very durable and portable. You don’t need to install it so you can use it just about anywhere, giving you peace of mind and comfort wherever you may go.
The biggest draw of this product is it dry composting design. It separates liquid and solid waste so decomposition can be faster and odor-free. Leaks are also prevented by this design, making it a completely hygienic and sanitary option.
Topped with a comfortable seat and you’ve got a solid option for the best composting toilet for your small home, RV, truck, or boat.
To guarantee effective waste degradation, this product is equipped with a hand crank for mixing solid waste and peat moss which provides effective odor elimination. It also has a vent pipe with a fan to release the gases.
- Comfortable seat
- Little to no chance of leaking
- Sturdy and durable
- Easy to use
- Good height
- Great for boats, RVs, and other similar applications
- The handle can be hard to turn
- A bit pricey
Sun-Mar Compact Self-Contained Composting Toilet
If installing a vent that goes all the way up to the roof won’t work for you, the Sun-Mar Compact Self-Contained Composting Toilet is the best alternative to the other Sun-Mar item on this list.
These two products share a lot of the same features except one requires electricity to run a fan, and the other can be used without such.
This electric-powered composting toilet may be a bit complicated to install, but it doesn’t mean that it can’t get the job done. It’s very important to ensure that you have properly installed the unit as it has an emergency drain that you’ll want to work properly.
Otherwise, leaks and pooling can be a problem. With the proper installation, you won’t have to worry about runoff and cleanups as this unit does a great job in turning body waste to compost.
The first composting toilet to be certified by the National Sanitation Foundation, or NSF, you can be sure that this unit is the authority in quality and engineering for such products.
It’s such a shame, however, that not every owner of this Sun-Mar item properly installs their unit, causing them some inconvenience instead. This is why it’s very important to pay close attention to the instruction manual before putting a unit in place so you can avoid all the hassles improper installation can bring.
Durable and sturdy, this Sun-Mar product is also guaranteed to last for years. Even if you use it on a daily basis at home or on weekends in your cabin, you can count on it to help you answer hundreds of nature’s calls.
- NSF certified
- Large capacity but a portable body
- Odorless operation
- Removable footrest
- Installation requires some effort
- Doesn’t separate liquid from solid waste
Still debating a composting toilet or a flush toilet? See the Pros & Cons of composting toilets here.
SunMar also makes a popular pre-made composting cover material, although you can make your own blend for less money (see our DIY mix here).
Complete Buyer’s Guide to Composting Toilets
What are the benefits of using a composting toilet?
Let’s start this guide by getting you even more interested in composting toilets. If this system has piqued your interest, knowing just how beneficial it is for you might just give you more reasons to learn what these things can do. So, how can this kind of commode be beneficial for you? Here are a few ways:
Minimizes your waste production
As mentioned above, composting toilets are becoming more popular options for those who want to leave as little trace as possible on Mother Earth. As composting toilets can turn your body’s waste into something very useful, you can add one more thing to your recyclables and create less waste at the same time.
Then, there’s also the fact that you’re not contributing to the harmful waste being dumped in bodies of water. This problem is seriously plaguing aquatic ecosystems as human refuse creates marine pollution that can kill the living creatures in it.
Soil contamination can also be minimized by opting for these systems. Without pipes containing toxic waste running underground, you won’t have to disrupt soil systems and worry about the pipes getting damaged and polluting the land where it spilled.
Lowers utility costs
As some of these toilets don’t use water, you won’t have to worry about using so much water and racking up a high water bill. While you will have to get a few extras like bulking material to better manage the decomposition process, many options for these things are renewable and are also already considered waste. By opting for sawdust and coco coir, you can ensure proper decomposition of your body waste and recycle other production processes’ waste at the same time.
You also get to cut down on sewerage and plumbing maintenance costs with composting toilets. As these systems are very easy to maintain, you can expect to pay less for keeping your home in top shape.
Solves sanitation problems
In places where indoor plumbing and sewer systems are unavailable, waste disposal can be a nightmare. You can’t just go wherever you feel like it because the refuse can contaminate the water and spread diseases. By effectively containing and recycling human waste into fertilizer, you’re not only providing an efficient solution to poor sanitation, you’re also benefiting from the process at the same time.
Makes you self-sufficient
In the case of droughts and failures of established sewage systems, you won’t have to worry about human waste disposal because composting toilets will still work, even with little to no water for flushing waste down the drain.
What a composting toilet is and how it works
Those who have never heard of a composting toilet before may be a bit confused about what it is. It’s actually pretty straightforward and the name says it all: It’s a toilet that turns your waste into compost. Instead of sending your body’s excretions down a septic tank or sewage system, it has a composting unit that processes the waste and turns it into fertilizer.
It works the same way as your garden composting system does, except it has an addition of a toilet unit where you eliminate bodily waste with ease. They often look just like a traditional toilet so you won’t have to feel like you’re roughing it out or as if you don’t live in the 21st century. The waste will then be transferred to a composting unit where the magic happens
Inside the waste container, oxygen is supplied to speed up the decomposition process through anaerobic process. Heat is also used to help pick up the pace and make the waste’s degradation even faster. Moisture is removed through the help of a leachate system, and ventilation is provided to release the evaporation of such. The growth of specific bacteria is also encouraged to help assist in the process.
All of these assist in breaking down the waste and eliminating most of the harmful ingredients in human waste. In the end, you’ll get a high-quality fertilizer that you can use as a soil amendment for gardening and farming.
Types of composting toilets
There are a few different types of composting toilets that you can choose from. They largely differ in construction, engineering, and capacity, making them suitable for various needs. There are two general types that you need to be aware of.
Self-contained composting toilets
Again, as the name suggests, these toilets hold and process the waste and turn it into fertilizer right inside the unit. This makes them a bit bulkier than your regular toilet, but most units don’t really take up too much space to be too cumbersome for tiny bathroom spaces. They also look a lot like regular toilets, so you won’t feel weird using them.
As these units don’t have to move the waste from one spot to another, there’s no need for it to have a flushing system. To eliminate odors and speed up the waste’s decomposition, you’ll have to use bulking materials like peat moss or sawdust instead. Despite the simplicity of their design, they still have a fan to ensure an ample oxygen supply and a heater to speed up the composting.
Because of the smaller waste storage, these units will also require more frequent emptying. This makes them more suitable for limited use. Some also use additional composting barrels if they opt for these in their homes.
Central system composting toilets
Designed for more extensive use, this type of composting toilet has a separate waste tank where the composting takes place. The waste storage can be large in size it can also be placed underground or outside, giving you options when it comes to extracting the compost. This design, however, makes them in need of a flushing method, so it’s also available in two subtypes:
- Micro-flush toilets use a small amount of water to push the waste from the toilet to the waste tank. They also require additional measures to get rid of moisture
- Waterless toilets, as the name suggests, do not use water. Waste is sucked through a vacuum instead to move it to the composting unit. While it’s a great option for locations without limited water access, it requires the waste storage to be located under the commode, which can complicate the compost extraction later on.
Choosing between a self-contained and central system is one of the first steps you should take if you’re planning on switching to this plumbing-free arrangement. When weighing your options, you should make sure that the capacity of the waste container is proportional to the amount of waste your household can produce. Maintaining self-contained composting toilets can get tiresome if it’s used on a daily basis in a regular home, so you should consider such factors before making a decision in this particular aspect.
Common myths and concerns about composting toilets
Because composting toilets are not exactly the most attractive options when you have indoor plumbing readily available, it’s natural for people to have misconceptions against such a setup. You might also have your own questions that can make or break your decision to go for install one of these systems at home. So, to help you better understand the whole idea of using these toilets, here are a few common myths about composting toilets and their clarifications.
Myth: Odor is an issue.
Fact: Odor control is possible and easy.
Composting toilets won’t stink if they work perfectly and if you use them the right way. There are measures to control bad smells; you just have to make sure to stick to them to avoid any hassle along the way.
Myth: Composting toilets are not sanitary.
Fact: If you use composting toilets the right way, there won’t be any sanitation problems.
There’s no need to come in contact with refuse with these toilets, so you can be guaranteed that it’s also a highly sanitary option to deal with human waste. If you make sure to wash your hands after doing your business and keep the system in its optimal shape, you don’t have to worry about diseases that are commonly associated with fecal matter.
Myth: You can’t use normal TP.
Fact: You can use just about any kind of toilet paper with a composting toilet, unlike special toilet paper for RVs and boats.
Because these systems are designed to degrade the waste that enters the composting unit, you don’t have to worry about toilet paper getting flushed down after you relieve yourself. These items can also disintegrate in the composting process. However, most experienced users recommend switching to biodegradable and rapid-dissolving varieties to further speed up its decomposition.
Myth: Flies will be all over the place.
Fact: Taking the right measures can help you avoid such a hassle.
Using sawdust and other bulking material will impede fly infestation. You can also use mesh wire to screen out insects as well as keep lids tightly closed so these bugs won’t get into your waste container.
Myth: Composting toilets are illegal in some parts of the US.
Fact: There are specific technicalities to the legality of these systems, but they’re generally legal and won’t get you in trouble should you wish to opt for one.
While you will need to get a permit to build a composting toilet system in your new home in some states, this shouldn’t be too different from getting a permit for a septic tank installation. More states are welcoming these alternative systems, although measures are still being taken to regulate them. In many states, site-built commodes are not yet allowed, so make sure to look for an NSF-certified toilet instead.
This means that in most regions, composting toilets are legal with specific limitations. You can’t transport the “humanure” or finished product outside your property lines, and you have to maintain at least one traditional toilet on your property. Ensuring that you’re not causing a public nuisance is also a must, as complaints from neighbors can be deemed as misconduct on your part.
What to look for when buying a composting toilet
Interested in getting this kind of commode for your home? Here are a few things you should look for in the best composting toilet for your needs to ensure effective waste disposal and your convenience.
The capacity of your toilet’s composting tank should be proportional to the amount of waste your household can produce.
Ease of maintenance
To keep composting toilets hygienic and in top shape, you should be able to easily clean and empty them.
Additional devices like a fan and heater assists in the decomposition process of your waste, so you should also pay close attention to them. It’ll be best if they are energy efficient so you won’t have to create waste while recycling your refuse.
While these toilets are not porcelain thrones, you will still want to be comfortable when using them. Be particular in the sizing and design of the commode so you won’t have to struggle every time you need to use it.
Increased demand for composting toilets.
With the increasing interest in tiny and off-grid homes, certain home components that were once deemed to be too “hippie” are now becoming in demand. As more people see just how bad things are turning out for Mother Nature, those who are becoming more environmentally conscious are willing to take steps to help out.
Many of today’s current trends, including the use of composting toilets, can be some of the most promising ways to minimize your waste and carbon footprint. However, getting started can be quite tricky. So to help you out, here’s a quick guide to how these things work and how they can be a great fit for your home.
What is a composting toilet?
Before getting to the nitty-gritty of these products, you might want to know what a composting toilet is. To put it simply, this is a type of commode that uses a different method of waste disposal. While it looks a lot like a regular toilet found in most modern buildings, the fact that they are not connected to a septic tank or sewer system makes them different. Often, they don’t have water or use a lot of it to push the refuse to the holding tank.
But what really sets composting toilets apart from all the other types of johns is the fact that it is engineered specifically to turn your waste into compost. This kind of recycling helps minimize every kind of waste your home can possibly produce, turning even the trickiest of refuse into something very useful.
With its minimal to no use of water, composting toilets are effective solutions to locations where access to running water is absent or limited. They can be used in state parks, remote vacation homes, off-grid homes, or even in developing countries. More households who are trying to make their lifestyle greener are also opting for this type of toilet despite being in the city or suburbs.
There are a few types of composting toilets to choose from. They differ in terms of how they process the waste and where they store it. The different varieties available today are:
Types of Composting Toilets:
Self-contained toilet: These commodes store the waste right inside the unit. These products have special containers for the waste and are installed right inside the bathroom. They’re often bigger than regular toilets as they need the space for the waste compartment, but they’re not too big or bulky and do not consume too much space.
However, this also means that their capacity depends on the size of the toilet as the waste has nowhere else to go but inside. This makes them more suitable for seasonal use.
These toilets can optionally make use of a fan to aerate the waste and a heating device to help speed up the evaporation of the refuse’s moisture. Others don’t use these and just sprinkle an absorbent carbon material on their toilet to eliminate foul odors and create air pockets to start the aerobic processing and dry out the waste.
Central system composting toilets are much like a regular toilet as it has a separate place where your waste is stored. It can be underground like a normal septic tank or in an above ground sealed container located outside. They also look like traditional toilets, so they can really be a good option if you want to transition from a regular commode to an eco-friendlier one in your home.
With this type of toilet, however, the waste has to move from the toilet to the waste storage. This is why you can find central system toilets in two different flushing methods. These are also considered as subtypes of this composting toilet variety:
Micro-flushing central system toilets
This type makes use of a small amount of water to flush down the waste from the toilet to the waste compartment. The water consumption depends on the construction of the toilet, although most require a very minimal amount of a pint or half a liter.
Waterless central system toilets
As the name suggests, this system actually eliminates the need for using water to flush the waste out of the toilet. To drain the refuse to the composter, it uses a vacuum. These units are equipped with fans to pull the waste down to the storage, ensuring an odor-free operation. The only drawback is that you can only use this configuration with an underground composting unit.
There are a few other types of composting toilets using varied designs for moving waste from the john to a specially designed compartment, but these three are the most popular varieties that are easily available today.
How do composting toilets work?
After getting to know composting toilets better, you may have an idea of how they work. However, this may not be enough to convince you to give it a shot, so a more detailed discussion is in order.
The first thing that you need to know about how composting toilets work is the fact that they need two integral components to get the job done. The first one is the actual unit where you sit down and do your business. Then it needs a collection/composting unit that requires storage, a ventilation mechanism, a leachate collection system, and an access door where you can quickly extricate the compost. Some units also have a heating element, especially when the unit is located in a cold region.
The actual toilet is really a very simple fixture. It’s basically a stool with an opening for the waste to go through. The collecting unit is the more complex part, as it’s where the magic happens. Each component plays a huge role in the process starting from the flushing.
Both the ventilation mechanism and leachate collection system play huge roles in controlling moisture in your composting unit. As manure needs to be dried out and fully decomposed to become fertilizer, these two things are necessary to get jumpstart the process.
Using an aeration device or additive will help ensure an ample oxygen supply and pick up the pace for the aerobic process, while you can count on the leachate collection system in further controlling moisture in the tank. A vent will complete the process by guaranteeing that the evaporated liquid will be removed completely and won’t be reabsorbed by the refuse.
Some leachate collection systems also entirely separate liquid from solid waste, so your composting unit won’t have to deal with ammonia which can impede the growth of beneficial bacteria that help in the decomposing fecal matter.
The heating device is also an essential part of most composting units as they speed up the degradation of the collected waste and evaporation of liquids that could have gotten in the mix. Maintaining warmth for self-contained units is a must, as these things have small storage spaces that you’ll need to empty right away. Central systems also make use of them, but because of their larger capacity, it will need to generate more heat to do its job effectively.
You can also opt not to use a heater, but when the temperatures drop, it will only function as a holding tank. You’ll need to wait until the weather warms up for the decomposing to resume and to extract the compost.
Composting toilets FAQs
Can you still use toilet paper?
You can still use toilet papers as long as it is the rapid-dissolving kind. Thicker and non-biodegradable varieties won’t easily break down in the composting tank and may even impede the process, so avoid them at all costs.
Is it smelly?
A composting toilet that is fully functioning and properly installed shouldn’t have odor issues. If you’re really worried about the smell, you can also use bulking materials to get rid of the smell, even when the composting tank is secured.
How often do you need to empty the composting tank?
You can only take out the tank’s contents when they’ve fully transformed to fertilizer. This can take a while before you have to empty your composting unit because of this. It also depends on the size of the tank, as some will fill up rather quickly and require more frequent emptying.
Do you need a permit to install a composting toilet?
There can be local regulations regarding composting toilets, so it’s best to check with your local authorities before installing one.
Are there any contamination concerns when using fertilizers made from human waste?
While fertilizers made from human waste are a lot like the garden-store variety in terms of content and nutrients, pharmaceutical ingredients can be a concern. As most chemicals aren’t completely absorbed by the body and can be released through the body’s solid waste, they can reach the fertilizer. Some experts warn that they can contaminate groundwater if used near a water source, so consider the medications your household takes in before opting to use one of these commodes.
How do you prevent a composting toilet from stinking up your house?
Composting toilets are a great earth-friendly way to get rid of your waste without needing a sewage line. However, they can get smelly. Here are a few ways to counter the smell.
When you want to be as eco-friendly as possible, there’s nothing that can beat composting toilets when it comes to sanitation. This stems from the fact that it uses no water, does not connect to the sewage system, and it creates an all-natural fertilizer. The natural processes of composting naturally and cleanly deal with the waste. This has become the preferred method of waste disposal in out-of-the-way places like national parks, cottages, and even some developing countries.
You can implement this in your own home. This may seem too much for an urban environment; however, if you’ve got a house with a low enough basement, it is possible to add a composting toilet to your home. The big concern of many people is possible odor.
The truth is, modern composting toilets hardly smell. They need to be properly maintained though. When you start smelling bad odors from your composting toilet, then something is most likely wrong. Here’s a brief introduction to composting toilets and how to ensure that they don’t stink up your house.
How they work
Before proceeding, you need to know how a composting toilet works. You just don’t dump everything down there and hope for the best. You need to understand how it operates and ensure that you get a good experience from it.
The first thing you have to understand is that 90% of the waste that enters the toilet is 90% water. When this evaporates, the remaining 10% can then be used as fertilizers for local agriculture or just your garden. Depending on how big your composting chamber is, you can get a lot of fertilizer out of it.
You need to determine what sort of composting toilet you’re going to want. Some composting toilets can service an entire home, while others are standalone. Smaller composting toilets can operate independently and without water, while larger ones can be like normal flush toilets or be waterless, too.
The heart of it all is the composting chamber. Whether it is large or small, there needs to be a balance between the oxygen, moisture, and heat inside. This is to help the bacteria process the waste and convert it into compost. When it is done, the bacteria will have completely broken down and the pathogens and viruses in the waste become harmless.
A proper composting toilet will be able to do the composting process safely. In addition to that, it will evaporate all of the moisture from the composting chamber. To start the composting process, there is usually a mix of carbon-rich organic material mixed in, like wood shavings and the like. There should also be soil in the compost mixture.
To maintain the mix requires two things: ventilation and heat. Most of the time, you will need a minimum temperature of 65° Fahrenheit inside the composting chamber. This is not a natural heat level so you will most likely need to use a heater. Most of the time, this is electrical in nature.
Usually, there is an exhaust pipe that leads out of the compost chamber. A small fan sucks up the humid air—which is necessary to initiate the process of evaporation. You want the moisture to be removed and result in a dry and easily usable compost.
Besides the heating and the vent, you will also need a maintenance door for future additions of organic materials. A good compost heap has a 30:1 carbon to nitrogen ratio so you will need to constantly add more material.
Finally, there is the extraction window. This is usually at the very bottom of the composting chamber. This is where the fully processed compost is removed to give more space inside for future additions.
Why the smell?
Composting produces quite a few byproducts. This includes chemical gases like ammonia, hydrogen sulfide, nitrous oxide, and more. However, a lot of these don’t really smell. They have a minor scent but they can be easily ignored.
When you start smelling foul odors coming from your composting chamber, something is wrong with your composting mix. Here are some of the possible reasons:
Too much moisture
Wet compost is natural. You need a certain amount of moisture for the bacteria that do the composting to spread. Moisture also provides part of the fuel for your bacteria—even they need the equivalent of a drink. However, too much water and they won’t be able to do their job.
There is no oxygen
Another important part of the balance in the composting mix is oxygen. It is a mix of waste and oxygen that starts the entire reaction. Without one or the other, the composting process won’t be able to happen.
It lacks microorganisms
The composting process happens because of the presence of bacteria. Without bacteria to process the waste, it will just stay there. You will need a natural compost starter which has bacteria and other living organisms. If your compost pile has “died,” you’re going to need to mix in a new batch.
You made a mistake in the mix
Finally, for the composting process to continue, there needs to be a balance of greens and browns. This is the carbon and nitrogen material from other organic compounds and waste. If there is an imbalance in the mix, then you can expect that the composting process will not work as well. Too much green and your pile will smell like ammonia.
How to avoid it
Avoiding these problems can be pretty simple. Ensure that your composting chamber has adequate ventilation by regularly checking its ventilation fan. This regulates the moisture and oxygen levels of the compost heap.
Besides that, you should regularly add to and mix around the compost heap. This lets the bacteria spread around while also adding greens and browns to the mix. It also exposes other parts of the heap to oxygen.
Overall, you should do maintenance on your composting chamber at least once a week to ensure that it is well-maintained and working properly.
Self-contained composting toilets may seem like they require a lot of work for a regular household, but with all of the benefits that you’ll enjoy from these products, it’s all worth the extra effort of frequent emptying of the waste container. With ample information and a strong commitment to making waste disposal work despite the lack of water and indoor plumbing, you’ll surely enjoy having a composting toilet at home.
There are so many reasons why you should give composting toilets a shot. Not only are they good for the environment, they can also help you reduce utility costs at home. With less water used, freedom from septic tank hassles, and the elimination of the need to buy fertilizer having a composting toilet can be very beneficial to many. It’s also not as complicated as you might expect it to be, so it really shouldn’t be a big change to use one of these instead of a traditional toilet.