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The Best Composting Toilets [2021]

Trying to reduce your water consumption? Or just fitting out your tiny home or RV? Keep reading to discover the very best composting toilets available to buy today.

Composting toilets take human waste and make compost – useful, right?!

Best of all, they do it without using any water and minimal energy.

They’re an eco-friendly and efficient waterless toilet choice for people living off the grid, in smaller spaces such as an RV, or in remote homes which have no access to a proper septic system. They’re also great options for installing in vacation cabins and tiny houses.

Composting toilets will save you money, reduce your water usage, and provide you with more productive soil.

However, they don’t come cheap. To make your decision about which one to buy a little easier, I’ve rounded up our picks of the best composting toilets you can buy.

The list is split into two sections, self-contained and separating toilets. You can read about the differences between these two types of composting toilet below.

Quick Picks

Self Contained

Nature's Head Self Contained Toilet
A small and compact waterless toilet with no compromise on capacity. This toilet is designed to stand the test of time, even in harsh conditions.
Separating

Separett Villa 9215 Waterless Toilet
You don’t have to worry about disposing of urine with this separating toilet, it can be drained straight into your grey water system.
Budget

Sun Mar GTG Composting Toilet
This waterless toilet separates wet and dry waste, while using a fan system to prevent odours.
Table of Contents

What Are The Different Types Of Composting Toilets?

I’ve discussed two main types of composting toilets

  1. self-contained
  2. separating toilets (I self-coined this one)

The main difference between the two toilets is where the composting takes place.

In a self-contained toilet, the composting takes place in the toilet. With a separating toilet, the waste is collected and composted elsewhere.

There is another type of composting toilet known as a central system, which I haven’t included.

These systems have large tanks that are installed under your house or outside. All the waste is flushed into these tanks, where it gets composted.

They have substantial capacities but are also much more expensive. The toilets I’ve here featured will be more than sufficient for most people’s needs.

Self-contained composting toilets

These toilets have an inbuilt composting function.

The waste is collected in a container along with some composting materials (coco coir is popularly used). You need to rotate it periodically. This churns the compost and provides it with oxygen. Some people also like to add worms to the toilet as they speed up the composting process, but it’s fine with or without worms.

When the compost is ready, you simply take it out and use it as you wish.

Different toilets have different ways of dealing with liquid waste. Some collect it in a separate container, while others use smart technology to evaporate it.

Advantages

  • No dealing with raw waste
  • Produces ready-to-use compost
  • No bags needed

Disadvantages

  • More moving parts and technology can mean more maintenance
  • Requires composting materials

Separating composting toilets

These toilets tend to divide the urine and solid waste into two different containers, where they’re dealt with separately.

The wet waste can be disposed of or used. You could pour it down the drain or dilute it and use it as a fertilizer.

The solid waste is dried out and can then be taken directly from the toilet and put into an outside compost bin (or any other approved solid waste disposal area).

Advantages

  • Sleeker, better-looking designs
  • Can be cheaper
  • No composting material is required
  • Doesn’t require churning

Disadvantages

  • Have to deal with raw solid and liquid waste
  • Urine waste can fill up quite quickly

Electric vs Non-Electric

Most composting toilets today come with a built-in fan and require a power supply to operate.

Usually, the fans only need a small 12-volt battery to work, which you can charge with solar power.

However, if you want to live totally off the grid and use no electricity there are also non-electric options available.

You’ll need to keep these toilets in a large airy space. Otherwise, they might start to smell!

Best Self Contained Composting Toilets

My picks for the best self-contained composting toilets.

Nature’s Head Self Contained Composting Toilet

Nature’s Head toilet is self-contained and (in my humble opinion) the best composting toilet you can buy today.

It was originally designed by two sailors who weren’t happy with any of the products available to them. They decided to solve this problem by making their own.

They sought to make their toilet as durable and user-friendly as possible. This is very apparent in the final product.

It’s the smallest toilet on my list, but there’s no compromise in capacity, which is why I rated it as the best composting toilet for RV’s.

If compost is too wet, this will inhibit the composting process. Nature’s Head has designed the toilet to separate the liquid waste from the solid waste to prevent this.

The liquid waste is collected in a container that you’ll need to be empty every few days.

The solid waste is left to compost in a different container, which you can churn using the spider handle. The toilet has an inbuilt fan to keep air circulating. This gets rid of any smells and also helps the composting process.

The urine tank is translucent, making it easy to see when it’s getting full, and you’ll know the solid tank is almost full when the handle becomes difficult to turn.

One downside to this toilet is that you need to lift the whole toilet up to empty it. This design helps to save space, but some users find it annoying.

Natures Head sells a different version of this toilet with a crank-style handle instead of the spider handle.

Both handles are made using stainless steel, but the crank handle is two inches longer. Users can find this more comfortable to turn.

Pros
  • small compact design
  • odorless
  • easy to tell when containers are full
  • durable
  • easy mechanism to churn the compost
  • fan ventilation system
Cons
  • you have to dispose of the liquid waste yourself
  • you have to lift up the entire toilet to reach the compost

Sun-Mar Excel Composting Toilet

Sun Mar’s NSF certified self-contained toilets are made with a patented three-chamber design.

Due to this advanced technology, Sun Mar’s toilets tend to require a larger budget.

Unlike Nature’s Heads toilet, this composting toilet deals with the urine waste itself, so there’s no need for you to empty it. In other words… it’s low maintenance.

All the waste is collected in San Mar’s BioDrum (the first chamber), which creates the ideal environment for composting. The drum has a handle making it easy to churn, and the inlet automatically closes when you turn it to prevent any spillages.

The toilet controls moisture levels in the compost by draining any excess liquid (the urine) into a temperature-controlled evaporation chamber. Keeping optimum moisture levels speeds up the composting process, meaning it will be ready faster.

The third chamber is a collection draw that gives the user easy access to the ready-to-use compost.

This unit is electric and has an inbuilt fan. The system draws air in from outside to maintain a partial vacuum. This air aids with the composting and evaporation processes but also works to ensure no odors escape.

This is the largest toilet on my list so less ideal if you have minimal space.

However, this also means it has the largest capacity, which is why I’ve rated it the best composting toilet for high usage.

It’s worth noting that some users have reported clogging issues with their units and find the stepping stool provided to be flimsy.

Sun Mar also offers a smaller version of this toilet (33″ (L) x 21.5″ (W) x 28.5″ (H), and 48lbs) with a capacity of 1 adult (with continuous use).

Pros
  • large capacity
  • good for residential use
  • fast composting
  • no liquid waste to deal with
  • easy access to the compost
  • odorless
  • NSF certified
  • fan ventilation system
  • easy mechanism to churn the compost
Cons
  • some users have reported drainage issues and overflowing
  • expensive
  • stepping stool is not very durable
  • less compact

Sun-Mar Excel Non-Electric Composting Toilet

This is the only non-electric composting toilet on my list, making it the best composting toilet for living off the grid.

The unit is very similar to the one above and uses the same three-chamber design. However, it lacks the electric elements such as the fan and heating.

This means that the composting and evaporation processes will be slower, and therefore, the toilet has a smaller capacity.

Also, because there’s no fan it can be hard to ensure proper ventilation. But, Sun Mar gets round this with a passive ventilation system which they say effectively removes any odors.

Even if you only plan to use this toilet occasionally, you’ll need to purchase a drain to help empty the evaporation tray.

Pros
  • non-electric
  • ventilation system
  • odorless
  • large capacity
  • no liquid waste to deal with
  • easy access to the compost
  • NFS certified
  • easy mechanism to churn the compost
Cons
  • composts slower
  • expensive
  • some users have reported drainage issues and overflowing
  • the stool is not very durable
  • less compact

Best Separating Composting Toilets

My picks for the best separating composting toilets.

Separett Villa 9215 Waterless Toilet

Separett’s dry toilet uses a cleverly designed, urine-diverting toilet seat to separate the wet and dry waste.

I think this is one of the best-looking composting toilets on my list and a good option for anyone who wants something discreet.

The urine is diverted down a drain, which you can easily plumb into a greywater system or holding tank. This means that you never have to worry about disposing of the urine, saving you time and hassle.

The dry waste is stored in a tank that’s lined with a compostable bag.

A fan dries the solid waste and gets rid of any odors through an air vent. When it’s full, you can easily remove the bag.

If you’re squeamish about toilet waste like me, then the Separett waterless toilet has some other nifty features to help.

  • The toilet has a screen covering the dry waste section that automatically opens and closes when you sit down to use the loo.
  • The waste bucket automatically rotates to ensure an even distribution of waste.

The waterless toilet comes with everything you’ll need to install it, but if you have children, then a must-have accessory is Separatt’s child seat. This ensures that your child’s waste goes where it’s supposed to!

Separatt also sells a very similar model, the Separatt AC 9200, which only connects to AC power but has a stronger fan. Separatt recommends this for extended venting.

Pros
  • no need to dispose of urine
  • automatic covering of solid waste
  • fan ventilation system
  • Intertec ETL certification
  • sleek design
  • odorless
  • easy to clean
  • easy access to the solid waste via a hinged seat
Cons
  • lots of moving parts could mean more maintenance

Separatt Weekend 7010 Waterless Toilet

The Weekend is a smaller, more budegt version of the Separatt waterless toilet I talked about above.

The small size makes this a top choice for people with limited space.

However, it comes with a trade-off in capacity. Separatt only recommends this toilet for lower usage applications such as weekend homes.

The toilet has no moving parts apart from the fan, which keeps it well ventilated and odor-free. This means there’s no automatic lid to cover the solid waste bin as in the Villa model so you can see the poo when you open the toilet lid.

There’s also a slight difference in how you access the waste. In this toilet, you have to remove the whole top half of the toilet. In the Villa model, the seat is hinged.

All other features are identical to the Villa model.

Pros
  • budget-friendly
  • odorless
  • small and compact size
  • fan ventilation system
  • no need to dispose of urine
  • sleek design
Cons
  • lower capacity

Sun Mar GTG Composting Toilet

This no-fuss waterless toilet from Sun-Mar is the best budget composting toilet on the market. It’s simple but effective.

Similar to other waterless toilets, its design separates the urine and solid waste into two separate containers. There’s also a built-in fan to dry the solid waste and a vent to remove any odors.

The toilet seat is removable, giving you easy access to the waste below.

Sun Mar doesn’t provide any bags with their toilet. However, if you want to make waste disposal a little easier, you can purchase your own compostable bags and use these to line the solid waste bin.

A disadvantage with this toilet is that it’s hard to see if the liquid tank is becoming full without removing the toilet seat to check.

Furthermore, it doesn’t come with any extra tubes to direct airflow out of the vent. You’ll have to buy these separately if you want them.

Pros
  • budget-friendly
  • simple design
  • compact and lightweight
  • easy access to the waste
  • fan ventilation system
Cons
  • hard to tell when containers are full
  • doesn’t come with all the parts needed

Reliance DIY Portable Composting Toilet

While not as fancy as any of the other compostable toilets I’ve featured, this DIY option is very affordable and great for anyone looking for a short term fix.

The sturdy container can hold 5 gallons (although I doubt anyone would want to leave it that long!) and has a toilet seat for comfort.

You can line the bucket with a compostable bag, do your business, close the lid, and then throw the bag in your composter when it’s getting too full.

If you’re worried about the bag splitting, I recommend double bagging.

Also, keeping a small bucket of cover material (coir or sawdust) near the loo for people to scoop in as needed will help minimize any odors, plus soak up excess liquid.

I’ve rated this the best portable composting toilet. You can carry it with you on camping trips or weekends away and relieving the worry of where you’re going to go to the toilet!

Pros
  • portable
  • cheap
Cons
  • no ventilation system
  • requires handing raw waste

Do Composting Toilets Smell?

A smelly composting toilet can be a big concern if you plan to install it in a small space, such as an RV or a tiny home.

The good news is – no, composting toilets don’t smell.

The next question on most peoples lips is, how can they NOT smell?

Pretty much every composting toilet is fitted with a fan and ventilation system, which gets rid of any odors.

In a separating toilet, the fan dries out any solid waste, which stops it from smelling.

In a self-contained toilet, the fan works to ventilate the toilet and make the composting process as quick as possible. This eliminates any bad odors because composted material doesn’t smell.

A top tip is to keep a bottle of vinegar mixed with water next to your toilet and spray a bit on the toilet after each use. This will help get rid of any stubborn waste, and keep the seat clean and fresh!

Composting Toilet Buying Guide

Composting toilets are a big purchase in any household and one that can directly impact the quality of your living space, so you want to be sure you make the right choice.

I’ve come up with a few things you should consider before making your purchase. You can also look at my article on the pros and cons of composting toilets for more information.

Type of toilet

I outlined the two main types of composting toilets above, separating and self-contained toilets.

Both of these have different advantages and disadvantages that you’ll need to weigh up before deciding which one is right for you.

Self-contained toilet composting occurs in the toilet, whereas a separating toilet prepares the waste for you and the composting happens elsewhere.

Size / Weight

Size is an essential consideration for most people looking to buy a composting toilet. They’re great toilets for people living off the grid, in tiny homes, in RV’s and cabins, etc., but this means there’s often limited space, and every inch counts.  Be sure to check the exact dimensions of any toilet before you buy it.

Capacity

Depending on how often you plan to use the toilet, this is an important feature. If overloaded, the toilet will not function efficiently.

If you plan to use it in a residential space, then look for a toilet with a larger capacity and be prepared to empty it more frequently. For those planning on only occasional use, capacity is less of an issue.

Compost needs time in order to fully break down, so the longer you can go without emptying the toilet, the better.

What To Do With Composting Toilet Waste?

While it would be ideal for a composting toilet to leave you with nothing to worry about but ready-to-use compost, this isn’t always the case.

Before disposing of any waste I recommend you check your local council guidelines, as each council will have slightly different rules around waste disposal.

When dealing with waste from your toilet, it’s advisable to wear gloves and to wait at least 6-8 hours after the last use before removing any solid waste.

Liquid Waste

In composting toilets, it’s quite common to have the liquid waste separated from the solid waste. In this case, you’ll have to dispose the liquid waste every few days.

There are a few ways you can do this, depending on what’s convenient for you:

  • Pour it down a public toilet (uses water, but much less than flushing every time)
  • Pour it into your greywater system
  • Use an RV dump station
  • Use it as a fertilizer (not recommended if someone has a urinary tract infection, or takes certain medications)
  • Pour it out on some barren land where there’s nothing growing

Solid Waste

Next, you’ll either have dry solid waste to deal with or compost.

For dry solid waste, the best thing to do is put this in an already established compost pile.

If you don’t have access to one, other options include burying it away from any edible plants and leaving it to degrade naturally over time, or taking it to an approved waste disposal area.

For compost, depending on how long it’s been left and the conditions around your toilet, such as temperature, it may not be fully composted yet.

For this reason, I recommend you also add this to an already established compost pile, where it can finish composting. In a mild climate, full decomposition of human waste can take about a year. If the climate is colder, it can take 2 years. Hot composting is a good way to speed up the process.

Once you’re sure it’s fully composted then you can go ahead and use it!

Summary

Hopefully, you’ve found this guide helpful in choosing which is the best composting toilet for you.

Whichever one you chose, it’s going to massively reduce your water consumption and provide you with lots more healthy compost!

Founder at Yuzu Magazine

Veronica has a passion for all things eco-friendly. After growing up on a farm in Ireland, she went on to study Chemistry and Environmental Sciences. Veronica has also volunteered in many sustainability roles, including conservation efforts in Bangladesh and teaching Environmental Sciences to schoolchildren in Kenya.

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