What is the Difference Between a Cassette Toilet and a Composting Toilet?

Random toilet standing by beach and ocean
Table of Contents

Where to Go While on the Go 

Are you done with making frequent stops at questionable public restrooms where toilet paper ceases to exist? Over having to use the smelly RV toilet without any chance of privacy? Thankfully, there is a way to overcome those less convenient options with a portable toilet! You become the boss as these toilets are detachable and can be used anywhere and whenever you want to go. The only question you need answered is: which type of portable toilet is best?

Making the switch from a more conventional toilet choice to a portable toilet option can be a big decision! There are a lot of options and factors to consider. How can I clean it? Will it be comfortable? And most importantly…will it stink?? Not to worry! We have spent years studying the art of the portable toilet and what qualities make for the best ones! The two most convenient options we have found are the cassette toilet and the composting toilet. 

What is the Difference?


Cassette toilets are similar to typical, stationary toilets for vehicles. They have an extra clean, water tank in them that allows you to flush them and you can even have them installed. The difference here is that the waste from a connected, RV toilet goes and sits in a black water tank, out of sight and mind until you go to a dump station. Meanwhile, the cassette toilet has a miniature, portable version of that waste tank where solids and liquids (including chemicals) are mixed that will need to be thrown out by hand, more frequently. 

Composting toilets can be known as dry toilets, so unlike cassette toilets, they do not use water or chemicals in the storage of waste. Instead, they rely on a more natural composting process which can only be achieved by separating liquids from solids. This will mean that there are two compartments within these toilets which will need to be emptied out instead of the heavier, more bulky single container like from a cassette toilet.                            

While both of these provide options that are more compact, portable, and less smelly, there are qualities which should be noted when comparing the two. Here are four of the major differences between the two portable toilet options. 

Note: For the sake of this article, we will be comparing our Evo L to a similarly sized cassette toilet. The cassette toilet holds 5 gallons in the waste holding tank. The urine canister and the solids bucket of the Evo L hold 2.6 US gallons each (5.2 gallons total). Our other models have differing canister and bucket holding capacities.The calculations used to set the disposal timelines and costs are at the bottom.

Disposal Intervals

Any timeline for emptying your toilets will be based on several factors: how many people are using it, how much you drink, etc.. Based on the use of two people per toilet, here are some disposal timelines:

As cassette toilets need water or chemicals in their tanks, they will fill up and need to be emptied more frequently than composting toilets. This would typically need to be done every other day. Due to the chemicals used, the contents need to be disposed of in particular dumping stations. So a part of your day will need to be planned around driving to find one of these designated dumping stations which can become time consuming and inconvenient. 

With a composting toilet, that timeline will be moved back to only needing to be disposed of every 3-4 days! You also will not need to rely on specific disposal stations as your waste will not contain chemicals. You can just dump out the liquids canister in any public toilet or sewage or spread small amounts in natural areas. Then tie up your bag from the solids bucket and put it in a compost or a disposal area near you that follows local guidelines. An easy, quick, and clean disposal interval! 



What makes the more frequent disposal intervals needed for cassette toilets even more inconvenient is the time it takes to actually clean out the piece. A cassette toilet has both number 1 and number 2 combined in one, large tank area.

Most cassette toilets do come with a pipe or tube where you can release a valve to let out the contents of that waste tank. While this may seem convenient, the clean up after can be more difficult than meets the eye. This style of disposal opens up the door for splashing and spilling.

Another issue with cleaning is that toilet paper or other solids may get caught in the tube. The canister has no way to open it for you to see and really clean out the inside, you just would need to swish in your water and cleaner and hope that no solids are sticking to the sides. There is also a greater possibility for a stink as the smell from waste is caused by the mixing of solids and liquids. 

Interior Compost toilet

That stench is essentially eliminated from composting toilets with the initial split from the waste by the separator. The solids go into the back where they are kept dry with a litter which absorbs any moisture and smell. Bags would ideally (we very strongly recommend this) line the solids container which makes cleaning it as easy as taking out the trash.

The urine canisters just need to be dumped and rinsed (with diluted vinegar, not just water)! The liquid canister does come with an air-tight lid which is designed specifically to keep out any smell that may arise as you transport it.

As the two sections are separated, there is less risk of any solids sticking in places that you can't get to. The separator and the bag liner ensure a cleaner, better smelling toilet! 

Ecological Friendliness  


Cassette toilets typically have two holding tanks which each have the capacity to hold between 3 and 5 gallons of liquid in them. This is water which will have chemicals added to it and need to be emptied out frequently. Even when you dispose of the chemically treated water in the correct dumping stations, your waste and chemicals run into sewage treatment plants. This adds to the water waste we see even from just regular, flushing, home toilets. 

Composting toilets, on the other hand, save water as they use none! You will only need to use water for this toilet when you are cleaning it out. You also will not need to use chemicals in the cleaning of your composting toilet. The litter used in the solids bucket is recommended to be organic as that is the best way to prevent odor. Organic litter, toilet paper, and liner bag can be disposed of in composting areas when you are emptying the solids bucket. For cleaning, you would use a natural vinegar or citrus concentrate diluted by the water. By using these clean alternatives, you are saving water and having a positive impact on the environment! 

Long Term Costs

Initially, cassette toilets are more affordable than your typical composting toilet. They range in cost from about $70 to $200 while a composting toilet will be between $400 and $1,000. While composting toilets are more expensive upfront, the long term costs associated with a cassette toilet can add up significantly. 

Cassette Toilet

The main running costs associated with a cassette toilet are the chemicals needed in the holding tank. Usually, a bottle will cost $10 for a 32 ounce bottle, or a more environmentally friendly option will cost $20. Depending on the size of the tank, you will go through a bottle at least once every 8 cleaning cycles. 

Composting Toilet
For a composting toilet, you would just need the following: 
  • Litter: The most affordable and accessible litter option, wood shavings would be found for very cheap or even for free at certain home goods stores or carpentry shops.
  • Vinegar concentrate: One gallon of concentrated vinegar can be found for $20. This is to be diluted with water, so a whole gallon is meant to be a long term purchase. Only needing one every other year.
  • Composting bag: These can be found at grocery stores for around $5 for 25 3 gallon bags. These would only need to be replaced about once or twice a week depending on the amount of people using and the temperatures outside. 

Conclusions: One or the Other?

Both cassette toilets and composting toilets are made to be taken anywhere with you. While the possibilities to be able to “go” anywhere are opened up by these, why not choose the toilet which will make answering nature’s calls more eco-friendly, clean, and convenient? Even though cassette toilets are capable and familiar options, the longevity of a composting toilet makes the initial payment worth it in the end especially if you are a frequent traveler.


Trelino M outdoors

***Disposal Intervals and Monthly Running Costs***

Cassette Toilet Disposal Interval
The tank holds 5 gallons total, so there needs to be .8 gallons of chemicals and water inside the holding tank before use. This leaves you with room for 4.2 gallons of waste. If each #1 is on average .15 gallons and each #2 is .17 gallons, then between 2 people (5 pees and 2 poops per day, per person), you would fill up 3 gallons of the tank daily, making it so you would need to empty it every other day. That is not even including the water added from each flush which fills up the tanks even more quickly. 
Composting Toilet Disposal Interval
The Evo L holds 5.2 gallons. Again, each #1 is .15 gallons and each #2 is .17. With two people peeing 10 times a day then pooping 4, you would fill up just 2.18 gallons daily. 
Cassette Toilet Costs
$10-$20 for the cleaning chemical bottle (new bottle every 8 cycles, 2 cycles per month when having to clean out every other day). $.50 per day.
Composting Toilet Costs
Sawdust is free to use as litter. $.06 cents per day on bags (10 bags for a month if emptying every third day, $2 worth of bags divided by 30 days), $.03 per day on spray ($10 per year for vinegar, $.80 per month, divided by 30 days). $.09 cents per day. 

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