Find the best compost toilet for your house or RV with our reviews and buyer's guide. We've got everything you need to know about the installation and maintenance of these environmentally friendly toilets too.
Compost toilets are a great alternative to traditional flush toilets. They don't require any plumbing or water, and are much more environmentally friendly.
If you have a tiny house, holiday cabin, RV, or just care about your impact on the environment, then one of these could suit your lifestyle perfectly.
We've reviewed 5 of the best composting toilet systems below. See how they compare in the comparison table, before checking out the reviews that follow.
If you're looking for RV composting toilet reviews then we've got you covered too.
We've even compiled a handy buyer's guide and installation and maintenance tutorial for one of these innovative toilet systems.
The Top Rated Composting Toilets
In our opinion these are the top five environmentally friendly toilets currently on the market. Check them out in the comparison table before we fill you in on all the details with the reviews that follow.
Our Top Pick
Nature's Head (Spider Handle)
- Easy to maintain
- Great value
- Perfect for off-grid
- Looks like a traditional toilet
- Accepts solar & battery
- NSF/ANSI certified
- Suits medium to high use
Nature's Head (Crank Handle)
- Wider than spider handle
- Easy composting
Composting Toilet Reviews
These are the top 5 models currently on the market. We recommend the Nature's Head toilets, as they are durable and easy to use, but remain competitively priced. While the Separett model is the most convenient.
For those of you looking for an RV toilet we recommend taking a close look at the Nature's Head models. They are able to cope with transit better than the other more fragile models.
Nature's Head Toilet (with Spider Handle) *OUR TOP PICK*
This model from Nature's Head packs an impressive Amazon rating, and is also one of the less expensive composting toilets available. It has an innovative design which makes life in a small space that much easier.
It was originally designed for marine use and packs all of the features that are needed for making a success of a small space. Since it doesn't require a water supply or sewage connection, the installation is really easy. It is just a matter of connecting the hose to the outside to ventilate the unit, and connecting an electricity supply to power the fan. This isn't a complicated task and the unit ships with everything included that you will need (except the outside vent).
The fact that it was initially designed for the tight spaces and rough nature of life in a boat make this the perfect composting toilet for RVs too. This is probably the most durable model on the market.
Removing and emptying the waste containers is really simple. There are a couple of clips at either side of the liquids tank that need unhooked, and then you can lift it out by its handle.
The solids waste container (composting bin) is started with peat moss, which helps with the decomposition of the waste. This is said to last for about 90 uses before it needs emptied, but it can last much longer.
The solids bin has an agitator handle at the side (spider handle) which is well designed for use in tight spaces. This handle is used to mix the compost mixture. A cool feature of this model is that the handle can be mounted on either side of the unit (the ventilation hose can be mounted on either side too). This gives you extra options with the installation, which can make the whole process a lot easier.
This Nature's head model uses a simple system, but it is effective and trouble-free. It's environmentally friendly, energy efficient, and perfect for tiny spaces. It's also cheaper than the rival brands. This is our top choice and in our opinion the best compost toilet on the market right now. You can read our more detailed review here.
The Key Features
Bottom Line: This Nature's Head model offers amazing reliability and value for money. It's one of the least expensive toilets of this type available, but also one of the most compact, durable, and easy to use.
Sun-Mar Excel Non-Electric
This model from Sun-Mar is another that requires no water to operate and is odor-free too. Sun-Mar have been around a long time and are very experienced manufacturers of waterless compost toilets. This system requires no electricity and is perfect for life off the grid.
It uses two separate bins (solid & liquid). The solids bin will require emptying after around a month if being used by 2-3 people on a daily basis. It will easily decompose the toilet paper too.
This model has a minimalist design and is very compact. It was made with small spaces in mind and the handle is used at the front of the unit instead of the side. This means it can easily squeeze into a very narrow space.
The Excel is an NSF certified waterless toilet system. To receive its award it was tested at maximum capacity continuously for 6 months. It produced no odor over this time and produced safe, clean compost too. This model can handle quite heavy use and is designed for 2-3 people in residential use and 5-7 people for the weekend and vacation use.
The installation and maintenance of this unit are both very easy. Installation is just a matter of hooking up the ventilation vent. There is an optional electric fan that can be used if you need to install the vent with any bends in it.
Before using the unit for the first time a peat and microbe mix (supplied with the unit) is added to the compost bin. This helps with the decomposition process. Maintenance-wise, you must add some peat mix periodically and stir the compost mixture with the handle. When the time comes to empty the solids bin, it is easily removed in a sliding tray.
The Key Features
Bottom Line: One of the few NSF certified toilets of this type around. It's a quality operator that's built to last.
Recommended Reading: Check out our huge guide to portable camping toilets next!
Nature's Head (Standard Handle)
This is the other offering from Nature's Head. It retails at around the same cost and has many of the same features. The main difference here is the agitator handle.
This model has a standard handle which adds almost 2 inches to the width of the unit. The alternative model uses a special spider handle, which conveniently saves space while remaining functional. In my opinion, the handle of this model is slightly easier and quicker to use, but there is the trade-off for space.
This model has the option of using an electric fan. This would be useful if the ventilation shaft has any bends or is longer than 5 feet in length. The fan draws little power, but if you are using 110V power then you will need to use an adapter.
Like its sister model with the spider handle, this is the best composting toilet for RVs due to its durability and space saving design. Though this model is slightly wider. An RV composting toilet needs to cope with life in transit and this is best equipped to do that.
The Key Features
Bottom Line: Almost identical to the model with the spider handle. Probably slightly easier to use but sacrifices size.
Sun-Mar Compact *Smallest Composting Toilet*
The Sun-Mar Compact is smaller than the Excel model and is more suited to small households of up to 2 people. It may be smaller than the Excel model, but it is definitely more attractive.
It has an elegant, low-profile design and will squeeze into most small spaces. It is made smaller using Sun-Mar's patented Bio-drum. This is smaller at the front and bigger in diameter at the rear. A single agitator handle is used to stir the drum. It extends from the front of the unit. The fact that it recesses into the body of the unit is a nice space saving feature that the Nature's Head models lack. Having a front operated handle makes this model ideal for narrow spaces, but not quite so good for bathrooms that are short in length. This is one of the smallest composting toilets available.
The Key Features
Bottom Line: If you're really tight for space then this is the perfect option. It's the tiniest of tiny house toilets.
Separett Villa 9210 DC/AC *PERFECT OFF-GRID TOILET*
The Separett Villa is highly regarded by the off-grid community as a top quality electric composting toilet. The electric fan can be easily powered by the DC supply that a battery pack, solar panels, or wind turbines provide. Likewise, it is can also receive AC power if need be.
The Separett Villa has a unique pressure-sensitive seat. Once it senses that someone is sitting down, it will open the otherwise covered solid waste bin. At the same time, it even rotates the waste so that the contents are mixed. This is a huge help with the waste decomposition process. This makes this the only true self-composting toilet that we've included. The others require manual operation of a handle.
The fact that it doesn't have a handle for mixing the contents means that it is very compact, and measures only 18 inches in width. This makes it ideal for use in a small bathroom.
The 9210 is well designed and has convenience firmly in mind. Emptying the waste bin is the drawback of electric composting toilet systems like these, but this toilet makes that process really easy. Simply remove the toilet seat layer and then place the lid on the waste container to seal the bin. It then slides out quite easily for you to add the waste to your garden compost. It also looks pretty good and doesn't look quite as odd as some of these types of toilet can.
The 9210 has separate containers for the solid and liquid waste. By keeping them separate there is no unpleasant odor from the toilet. The toilet has a large capacity and Separett state that normal use by a family of four will require the solids waste bin to be emptied about every 3-6 weeks.
For those that wish to run the toilet using a DC power system, the requirements will vary according to location and installation. In general terms, a battery of 60-75 amps and cell size of about 25 watts would be sufficient. The unit will use 0.06 kWh every 24 hours. This low power consumption makes it perfect for tiny house or off-grid living.
The Key Features
What exactly is a composting toilet?
A compost toilet is a more environmentally friendly alternative to the traditional flush toilet. They use no water and instead create compost when the human solid waste is mixed with peat moss and microbes.
Most systems separate the liquid and solid human waste into two containers. The solid bin contains the compost mixture and can be left for months at a time with no unpleasant odor. The liquid container needs emptying more frequently. The container usually unclips and slides out, and can be easily carried using a handle. By separating the two types of waste, the compost can form more easily. It also prevents unwanted odors. Odors usually occur when the solids bin becomes wet.
These systems are ideal for those that are conscious of the environment, and also those who don't have access to a septic tank. By not using the sewage system these waterless toilets are less of a drain on the energy and water resources of the world. If you are a keen gardener then composting like this is an awesome way to help your crops too.
Why get a waterless compost toilet?
Here are 5 great reasons why everyone should own one of these innovative new breeds of toilet:
- Reason Number 1
According to The Guardian, "the water-flush toilet devours 30% of the UK’s water supply". That's a quite staggering statistic, and you can only imagine the amount of water that is wasted in this way worldwide.
We are much too used to our home comforts, and it is only now that we are starting to question our ways. A composter toilet is a good place to start making a change, and it will dramatically reduce the amount of water you waste.
- Reason Number 2
Despite what most of us think, the waste that gets dumped in the toilet isn't actually useless. The bin of a waterless toilet provides a rich fertilizer which will do amazing things to your garden. The fertilizer is 100% natural and free of charge.
- Reason Number 3
It will reduce your water bills. By reducing your water usage by up to 30% you can expect to significantly save on your water bills too. They costs more initially, but you can expect to save money in the long term.
- Reason Number 4
It's much better for the environment. Besides, saving water there are other great reasons why these toilets are much better for the world. Firstly, they reduce the amount of blackwater in the system that needs treating. Blackwater must be separated from grey water and then treated. These tasks require energy and resources.
These toilets also reduce the amount of sewage that is pumped into our oceans and rivers. By recycling, our waste is put to good use in the form of fertilizer.
- Reason Number 5
It gives you independence from the sewage system. Since, you don't require a drainage, septic, or sewage system, you are free to roam wherever you like. This makes these kinds of toilets perfect for tiny house enthusiasts and those that want to live off the grid. A composting toilet for RVs is also a great idea.
Pros and Cons
It's only fair that we offer a balanced opinion. Here are the advantages of waterless toilet systems against the negatives. We love these environmentally friendly toilets but they're not perfect. Let's see how the good stacks up against the bad.
- Great for the environment.
- Save water, reduce blackwater, recycle...
- Save on water bills.
- Flush toilets waste a huge amount of water.
- Space saving design.
- These are designed to work in tight spaces like RVs, boats, and tiny houses.
- Easy to install.
- There's no plumbing involved in the installation and no need for a septic tank.
- Produces compost for the garden.
- Get an endless supply of the best 100% natural compost for free.
- Odor-free operation.
- As long as you don't let the two containers mix and you empty them regularly then you won't have an issue with smell.
- Can be very expensive.
- Sadly, they are expensive and not an option for everyone.
- Have to be manually emptied.
- They require a bit more work than simply flushing and forgetting. The liquids container requires emptying quite regularly (every few days depending on usage).
- Not very elegant.
- They aren't the prettiest looking things in the world. However, they are very functional.
Installation and Maintenance
In this section, we'll explain how to install a compost toilet and also how to prep and dump the bins when the time comes.
These guys need no plumbing to install. You must make sure there is adequate room to remove the waste bins and to turn the agitator handle though (the agitator handle turns the solids bin to mix the compost).
Most models will attach to the floor using brackets. You will also need to run a ventilation hose to the outside. If the ventilation shaft is overly long or has bends in it, then you should install an electric fan to help the ventilation process. These usually run on 12-volt power.
Everything you need for installation is included with the unit except the outside vent (as these will vary depending on installations). The basic installation kit for the Nature's Head models contains:
- 5 feet of hose with ends inside vent flange
- 4 mounting bolts
- 2 mounting brackets and knobs
- 18” single pin cable for 12-volt fan
- Allen wrench (to install handle)
- Fuse holder and fuse
- Spray bottle
Before using one of these models it is necessary to fill it with peat moss mixture. Around two gallons of sphagnum peat moss or coconut fiber should be about right for most systems. It's important that the moss is not overly wet. It should be damp and not crumbly anymore. If it is totally dry then you should add a little water to moisten it. We'll explain this procedure more in the maintenance section.
The maintenance of these toilets involves a few simple things. The first one is that you need to turn the handle every time you add solids to the bin. This helps the composting process by mixing the waste and moss mixture.
The other maintenance tasks include just monitoring the liquid and solids bins, and making sure they are emptied routinely. The liquid bin will usually hold around two gallons of urine, and will probably need to be emptied every couple of days. The solids bin lasts for much longer periods of time. It really depends on how well the toilet is used. Once the solids bin is emptied you must add the peat moss mixture again before you use it.
The maintenance procedures are very similar among all the composting toilets for sale. The only differences really are how the solids are mixed and how the bins are removed. We've made sure to include this information in all of our composting toilet reviews.
How to Prep & Dump the Bins
One of the most common questions people have is about the dumping procedure. We're spoiled with regular flush toilets as they do all the work for us. Prepare to do a bit more legwork with a waterless toilet.
Preparing For Use
Before using the toilet it needs to be prepped with a mixture that aids the composting process.
Sphagnum moss or coconut coir can be used for this. They are pretty cheap to buy and are available from stores like Lowe's, Home Depot, and can even be delivered by Amazon.
The composting mixture needs to be hydrated so that it is damp but not wet or still crumbly.
The mixture then needs to fill the bin below the level of the agitator handle.
How to Dump the Bins
A compost toilet uses two separate bins: the solid and the liquid. Each need cared for in a slightly different way. Here's how to maintain the two bins.
It's time to empty the solids bin when the agitator handle becomes difficult to turn or the bin is noticeably full. Nature's Head estimate that two people using a toilet will need to empty the bin around every three weeks.
You want to always leave plenty of time for the waste to start the composting process before you dump it. This means you should wait at least 6 hours but probably more like 12 hours after the last solid deposit in the bin.
I recommend getting a second solids bin so that you can be a bit more flexible with the timings. With a second bin, you can always leave one bin to continue the composting process further before you dump it.
The process can differ slightly between manufacturers, but for the Nature's Head toilets the best way to empty the bin is to place a 13-gallon trash bag over the top (biodegradable bags are available) and tip the contents in.
It's really important to note that the solids waste mixture is not ready to be used as compost for edible plants just yet. It should be added to a traditional compost bin and allowed to sit for about a year.
Always be careful to check local dumping laws too. Each state has different rules with regards to the dumping of this kind of waste.
The liquids tanks tend to hold just over 2 gallons of urine. The Nature's Head models are said to need emptying every 3-4 days with two people using them. The tank is translucent so it's easy to see when it is approaching full.
Again, having a second tank makes life a lot easier when it comes to emptying. Especially, if at that time you are in a place where you can't easily dump it.
The liquids bin has a cap which makes it more easily transported.
Urine is actually a very good fertilizer and can be added to plants. Just make sure you're not breaking any local laws by doing so though.
Tips About Using a Composter Toilet
If you use a compost toilet correctly, you should never have any issues with odor or flies. Here are some top tips to get the most out of your new toilet.
- The lid should always remain closed when not in use. This prevents insects from entering and allows proper ventilation through the vent system.
- The sphagnum peat moss (recommended type) is easily available from Lowe's and Home Depot. A $10 bag should last a year.
- It is really important that the solids and liquids remain separate. If liquids get into the compost bin then the compost will be inhibited from forming and there will be an odor.
- Toilet paper can be added to the compost bin too. It will decompose a bit slower but will get there in the end.
- After adding to the solids bin you should always turn the agitator handle a few times. This helps the composting process.
- Seated usage is recommended. It is less likely that there will be a crossover of solids and liquids this way.
- Add some white vinegar to the urine tank if there is a strong odor.
For more top tips, check out this awesome video.
1. How much electricity does the fan use?
The fan draws less than 2 amps over 24 hours. The figure is likely to be closer to 1.5 amps. This would cost less than 1 cent a month.
2. Does the toilet smell bad?
No, because the solids and liquids are separated. The toilet will have a slightly earthy kind of smell. There will only be problems with an odor if you allow liquids to enter the solids bin. This is true for all composting toilets for sale right now.
3. How do I install it?
Installation requires no plumbing, but you will need to hook up the ventilation fan. Check out the 'Installation and Maintenance' section above for a video of the installation of a Nature's Head model.
4. Where do I get the peat moss?
Peat moss is available at garden stores and also at Home Depot and Lowe's. It is relatively inexpensive.
5. Do they take toilet paper too?
Yes, toilet paper can be disposed of in the toilet. It will take a bit longer to decompose than the other wastes though.
6. Where should I empty the waste?
The organic waste is great food for plants. Otherwise, it can be buried or stored away. If you're on the road, pay attention to local dumping laws.
The solid waste should be added to a garden compost bin and allowed to decompose for another year before being added to edible plants, fruit, and vegetables.
The liquid waste is full of nitrates which make it a great fertilizer too.
Before You Buy: Checklist
Check out the dimensions and configuration - If you are planning on installing a composting toilet in a tiny house then space is probably going to be tight. These toilets have handles that extend from the front or side (depends on manufacturer) that are used to mix the compost. Make sure you have enough space in your bathroom for the handle to be turned easily.
Plan for ventilation - A narrow ventilation shaft will run from the toilet to the outside of your home. For efficient ventilation, this shaft should be a short as possible with no bends in it. You do have the option of running a fan to increase the effectiveness of the ventilation, but it would be nice not to have to use one all the time.
Plan for the size of your household - These systems aren't designed for prolonged heavy use. If you have a big family then one of these toilets might not be a good fit. Composting toilets for tiny houses are a great way to be kinder to the environment and give you the opportunity to go off the grid.
Well, that's a wrap for our guide and compost toilet reviews. If you have any questions then we'd be happy to help. Drop us a message at the bottom of the page or on the contact page.
Keep an eye on us as we'll be posting again soon about the must-have accessories and appliances for tiny house living. Until next time!