12 Most Asked Questions About Composting Toilets

If you’re wondering about composting toilets, you’re likely to have a lot of questions about them, and while they’re complicated subjects that you can spend hours reading about, we’re going to cover some of the basics.

Here are the 12 most asked questions about composting toilets:

1. What Are Composting Toilets And How Do They Work?

Composting toilets are essentially toilets that are designed to eliminate or massively reduce the use of water for dealing with human waste. Most composting toilets separate solids from liquids, and divert the solids into a storage tank where they can be composted.

You will then add something to cover up the waste to prevent smells and help it break down quickly. Usually, the waste will remain in the tank for a few months, slowly composting.

After a while, the compost needs to be emptied out of the toilet. Most people transfer it to a dedicated compost heap for further processing, and it can then safely be used on non-edible plants around your garden, or simply allowed to return to nature if you don’t wish to use it.

Composting toilets are very popular in areas where sewers and mains water aren’t available, and are increasing in popularity as more people seek to return to a simple lifestyle and reduce their dependence on modern services. If you want to save water, they are a key solution.

2. What Are The Different Types Of Composting Toilets?

There are many kinds of composting toilets, and depending on where you are and what you’re looking for, you can probably find a customized setup that will suit your needs perfectly. Some require mains connections and electricity, and others are completely independent of these things.

However, there are two main categories: the self-contained and the split system.

A self-contained composting toilet, as the name suggests, is a toilet in which the whole system is contained in one relatively small space. There is no storage tank for waste elsewhere; it is in the same place as the toilet.

These systems tend to be preferable if you don’t have much space or you want a very simple system.

A split system has the tank for storing waste beneath the floor, rather than above it. The tank can be stored quite some way from the main system (e.g. in the basement or even in a separate area) if required.

This kind of system is used where space is less of an issue, and a bigger capacity is the priority. They can usually hold more than self-contained systems.

3. Are Composting Toilets Legal?

This depends a bit on where you are and what your setup is. Most states in America have laws that allow you to install composting toilets provided you meet certain criteria. You may have to have your system certified by the National Sanitation Foundation or by public health officials, and you may need a permit.

Often, if you have a traditional toilet linked to the sewage system with mains water, you can bypass any laws about composting toilets. However, you should still do careful research into both the state laws (or country if you are not in the United States) and any local laws that may apply to you.

In some places, composting toilets are not easy to legally install. It’s better to know your position and to request an exception or try to find a workaround than it is to install one illegally and end up in trouble.

4. Are Composting Toilets Safe?

Yes, when installed and used correctly, composting toilets are safe. The composting process should kill all pathogens and bacteria in the waste, making it harmless and useful in the garden. However, most recommendations say to only use the resulting compost on ornamental and non-edible plants as an extra precaution.

If you’re concerned about the safety aspect of composting toilets, ask yourself what it is that’s worrying you, and what the potential solution may be. If it’s the hygiene aspect, there are many things you can do to reassure yourself.

The point of a composting system is to deal with the waste in a way that is safe and effective, and as long as you follow instructions, composting toilets and the resulting waste shouldn’t pose any danger to anyone.

5. Do Composting Toilets Smell?

You might expect composting toilets to smell awful. After all, the waste is staying there for months, and traditional flushing toilets can smell pretty bad if we don’t use the water to take away the waste. However, composting toilets shouldn’t smell when used correctly.

You will have a “cover” material alongside the toilet, such as coconut shavings, sawdust, peat moss, etc. A scoop of the material will be added to the composting toilet after every visit, covering the waste. This helps it to break down and also prevents any unpleasant odors.

If you do have an issue with the smell, you can always add a few more scoops of this material. This should deal with the smell quickly. However, you don’t want to add too much; this will fill the tank fast.

In general, composting toilets shouldn’t smell of anything but the cover material. A slightly woody scent is perfectly normal; unpleasant odors are not.

6. Do Composting Toilets Need Water?

Most composting toilets do not need water, no. However, you should remember that you will need the facilities to wash your hands somewhere close to the toilet, and that you may need to wipe the bowl of the composting toilet from time to time.

Some composting toilets do rely on a small amount of water to flush. This is minor compared with the demands of a regular toilet (even a water-saving one) and will be very clear when you view the system’s advert. If you don’t have the water, you can easily avoid buying a system that requires it.

7. Do Composting Toilets Need Electricity?

Some composting toilets do require electricity nearby. If you need a vent for the room, for example, this may need a power source to run properly. You might be able to buy one that is battery operated if you don’t have an easy power supply near the toilet; others will need to be plugged in.

A few kinds of composting toilets also use electricity in the toilet’s own design. They might, for example, having a heating element that will kill any harmful bacteria in the waste and help the good bacteria to breed.

On the whole, you can run a composting toilet system with limited power – or without any, if you set it all up carefully and correctly – but some electricity is useful. If you don’t have access to any, you may want to consider installing solar panels to provide some. This can make your system much more flexible and give you more choice in terms of your toilet.

8. Do Composting Toilets Need To Be Emptied? How Often?

Unless the system is hooked up to the main sewers or a septic tank, your composting toilet will need to be emptied from time to time. Both waste and solids need to be removed to make space in the system for more. However, don’t let that instantly deter you; this does not have to be an unpleasant process.

How often you have to empty it will depend a lot on the system you have, how many people are using it, and your individual needs and habits. If you have a larger tank, you will not have to empty it very often. Small tanks will require more frequent attention.

Emptying the solid waste might be done every six months or so – but it could be less often if you have a large tank and few users. The composting process needs time to happen, so you ideally don’t want to be emptying the tank more frequently; you will then be dealing with human waste that has not broken down.

The waste may not have completely finished composting by the time you take it out, but most of it should be closer to compost than waste. Once the tank has been emptied, the compost can go to a compost pile for further processing, so it doesn’t need to be finished.

When purchasing your composting toilet, make sure that you take this into account and discuss your needs with the manufacturer. The tank must be capable of holding enough waste (with plenty of margin for error) that you don’t have to empty it on a regular basis.

If you have a toilet that separates the liquids, you may be emptying the urine compartment much more frequently. Again, the amount of time will depend heavily on usage, but it might be done about once a week. The urine can simply be diluted with water and then discarded in the garden; it is good for plants. Dilute it by about eight parts water so it is not too strong.

9. Can You Pee In A Composting Toilet?

Yes, most composting toilets will handle liquids as well as solids. If your composting toilet does not split the two, you will need a system that allows liquids to drain away from solids and prevents the composting chamber from getting too wet.

If you have a compost pile for food and garden waste, you will already be aware of how waterlogging prevents your compost from working properly. It gets rid of all the oxygen in the pile, killing off the good bacteria. An anaerobic compost pile stinks – and a composting toilet that has too much liquid with the solids may also smell bad.

If your system is not set up to handle liquids, you may wish to consider other alternatives, but most composting toilets are capable of dealing with both.

10. Can You Put Toilet Paper In A Composting Toilet?

Yes, you can put toilet paper in a composting toilet. It will break down along with the rest of the waste and simply disappear. The thinner the paper, the more quickly it will break down, but you can use any toilet paper you want.

Do not use wet wipes in a composting toilet. They contain microplastics and will not break down properly. Only toilet paper should be put in a composting toilet.

11. Can You Put Composting Toilets In RVs? How Does It Work?

You can put some composting toilets in RVs, but you need to check that the system you are installing is suitable. Remember that many composting toilets are not designed to be moved and shaken around, and the last thing you want is the toilet to spill its contents somehow.

Composting toilets designed for RVs tend to prioritize space-saving and will usually come with a fan system to ensure nasty smells don’t end up in the enclosed space with you. There are some great options out there that are perfect for an RV.

However, if you plan to put a composting toilet in an RV, you need to think about dealing with the end product. Many smaller systems suitable for RVs will need emptying once a month or so, and you will have to find a way to do this. Think about ways of safely disposing of waste that suit your lifestyle.

While composting toilets are a great solution to the ongoing problem of bathrooms in RVs, you will have to think hard about your setup and making it work for you. You are unlikely to have the storage space for a large tank, and if you’re traveling, you may not be able to compost the resulting humus. Think carefully before taking this option.

12. Can You Put Composting Toilets In Boats? How Does It Work?

Again, many composting toilets are designed to work well on boats, taking into account the small space and lack of flushing water, as well as the potential power constraints. However, the same issues apply; you will need a system for disposing of the waste once the composting toilet is at capacity.


Composting toilets offer a solution to many people who are living off the grid, don’t have access to flushing water/power, or are simply looking to reconnect with nature. They can be perfectly clean and hygienic when used correctly, and they are ideal for anyone who wants to save water – and the planet.