Are RV Cassette Toilets Good and Don`t Smell?

Campers come in various sizes, prices, and shape ranges. However, what makes them equal in requirement in a good toilet and need to drive to the dump station to empty the van’s waste tanks there.

This is unless you use cassette toilets in your RV. With these updated cabinets in your RV, caravan, or camper van, you will skip the hassle of long lines in the dump stations.

We traveled last year with our Eriba caravan which is equipped with Thetford cassette toilet and can confidently say it works perfectly.

What is a cassette toilet?

A cassette toilet is a permanent toilet that has a portable black tank. This toilet has taken the traditional camper toilet, and the waste gets into a small portable waste tank instead of getting to a waste tank. The waste tank is removable and rolls on wheels like a suitcase so that you can dump it at a dump station or a public restroom.

This might not be for everyone because some might find it uncomfortable to empty, but it is the best option for campers who often go off the grid.

Easy to handle RV Cassette Toilet
Easy to handle RV Cassette Toilet

How does the RV cassette toilet work?

The RV cassette toilet is permanently fixed to your RV toilet with a flush water tank or connected to an RV water system. Flushing water collected to holding tank that can be detached from outside and emptied at the dump station.

Its surface looks and functions as a standard fixed toilet and works similarly. You will do your toilet business, flush, and walk away. The only difference comes in the holding tank size and how to dump it.

The benefit of portable toilets is that holding tanks can be easily detached and dumped at the nearest dump station or regular sanitation. Another advantage is that it is easier to maintain in good condition or you can buy a new wastewater tank and replace it if needed.

RV Cassette Toilet Holding tank access form outside the caravan
RV Cassette Toilet Holding tank access form outside the caravan

What is the holding tank size of a cassette toilet?

The tank size is about five gallons, but the size can differ depending on the type of cassette you purchase. This makes it necessary to dump the portable tank every two to five days.

We used to make shorter trips and most of our journeys on caravan Eriba Touring Troll 530 take up to three days. We never emptied the holding tank during the road trip and do it once we are back home.

Eriba Touring caravans are mostly equipped with Thetford C400 series cassette toilets. Here are the most important characteristics of this toilet.

Bowl materialWhite durable plastic
Flush-water tank capacity15 Liters or 4 gallons
Waste-holding tank capacity19,3 Liters or 5 gallons
Waste-holding tank typePortable tank on wheels
Flushing system typeElectric yet flushing, full bowl coverage
Level indicator for flush-water tankYes
Level indicator for the waste-holding tankYes
Dimensions of toilet512 x 670 x 400 mm
Weight of empty toilet8,8 kgs

If longer travel periods between dumping stations are expected it is worth carrying a spare holding tank that is lightweight and may be used for the collection of gray water.

Since RV cassette holding tanks are rather smaller, so they are ideal for RVs with smaller spaces.

How long does a cassette toilet last?

The length of time that a cassette toilet can last depends on the capacity of the waste holding tank and the flush water tank. For instance, a standard five-gallon cassette toilet can last about fifty flushes.

The capacity of waste-holding tank

The amount of waste a holding tank will hold will determine how long it lasts. For instance, if the cassette toilet has a smaller waste holding tank, its lifespan will reduce and vise versa.

The capacity of the flush-water tank.

No matter how big a waste holding tank is without a flush water tank, a cassette toilet will be of no use. The size of the flush water tanks can determine the lifespan of a cassette toilet. If the tank is smaller, then it means that the lifespan will be limited, and the number of trips to dumping increase.

How to empty a cassette toilet

Here are the steps to follow when emptying a cassette toilet:

  • Empty the toilet bowl and close the blade handle
  • Open the cassette’s outside door and pull up the safety catch to push out the tank.
  • Roll the cassette or even carry it to a bathroom or dump station
  • While at the station or bathroom, remove the spout from the tank and lift the dump hole
  • Pour water into the waste tank while swishing it around and empty it.
  • Rinse repeatedly until the liquid flowing out becomes clear.

Types of cassette toilets

There are two significant types of cassette toilets based on the flushing technique. There is the manual flush cassette toilet and the electric flush cassette.

Tips for handling an RV cassette toilet

  • Do not use number two: This is usually for emergencies and should be avoided as much as possible as it can cause clogs and make dumping of the waste challenge.
  • Use proper toilet paper – rapid-dissolving toilet paper will not harm your cassette toilet and there is no need to put the toilet paper in the trash as it is simply not hygienic and doesn’t give any significant benefit.
  • Dump the waste frequently.
  • Keep the toilet clean.
Fixed RV cassette toilet makes your bathroom comfortable and odorless
Fixed RV cassette toilet makes your bathroom comfortable and odorless

Do cassette toilets smell?

The way you will use your cassette toilet will determine its activeness conditions. If you choose to use them as a number one choice, then their smell won’t be stinking. What can make your cassette toilet smell is choosing them as number two.

But you can choose to use and dump them immediately to avoid this problem. This will keep any unpleasant smell out of your presence.

Using chemical addictive helps to avoid unpleasant smells very much and should be used always.

Most of the time, the smell of cassette toilets increases when you choose to use them both for solids and liquids. Although you can also fix cassette toilets for emergencies, especially in your van, it is essential to keep them clean. Here is how you can keep it smelling fresh.

Dump the waste often.

Once you use it, make sure you dump the waste immediately after use. This will keep it fresh for further usage.

Don't wait until it's full.

One of the best ideas to keep your cassette toilet away from smelling is by emptying it before it is filled up.

Use cleaning chemicals

You can keep your cassette toilet away from unpleasant smells by cleaning it with chemicals and vinegar. Such detergents make them smell fresh and provide a conducive environment.

Leave some water on the cassette toilet bowl

This can be the best ideal for keeping your toilet from pumping back some smell from the holding tank. Keeping some water on the bowl will make sure there is a seal on the tank’s mouth to prevent odors from the smell.

Don't mix the solid with the liquid waste

Mixing such waste can increase the smell you need to keep emptying.

What chemicals are used in a caravan cassette toilet?

There are several main types of chemicals used in cassette toilets to maintain them in good working condition. Most of the producers use the same color-coded range of chemicals to help owners to use proper chemicals.

The most important chemicals are Blue and Green chemicals that may be supplied as a powder or liquid additives. The main purpose of these chemicals is to break down the toilet content and avoid smells and odors.

These chemicals are to be added directly into the holding tank with some amount of water. Commonly it is around one or two liters of water, depending on the capacity of the holding tank.

But what is the difference between blue and green chemicals? Blue chemicals are Formaldehyde based chemicals, but Green chemicals are Formaldehyde-free that are often called Bio or Eco-friendly chemicals.

Pink toilet chemical is an optional additive that should be added to the flush water tank. Flushing water with a pink additive protects the toilet bowl, disinfects the toilet, leaving it bacteria-free, clean, and removes bad odors.

Another chemical for caravan cassette toilets is cassette tank cleaner. In fact, it is an optional chemical and should be used depending on how intensive is the use of the toilet. Some manufacturer advises cleaning your sanitary two or three times a year, but you should decide if it is reasonable.

We use cassette tank cleaner before winterization of the caravan or during the season if an unpleasant smell seems to start to appear, but it has never happened so far.

How often do you empty a cassette toilet?

Using Cassette toilets without knowing how and when to use them can be challenging as they can result in an unpleasant smell. They need to be emptied after use, but often should you empty a cassette toilet? Although emptying a cassette toilet can be as well after use, it also depends on how often you use it. The recommended duration for emptying your cassette toilet is dumping the waste once after every two days of use.

Size and capacity of RV cassette toilet is about 5 gallons
The size and capacity of the RV cassette toilet is about 5 gallons

Cassette toilet shower combo

Cassette toilets can also be fixed with restrooms or showers that you can use to take a breeze of cold or warm water. But using such showers also needs some ideas not to terminate the operation of the cassette toilet.

First of all, the tank has to be emptied before taking any shower. This is to avoid the holding tank becoming filled up quickly if it was about to be full.

There are other things that are kept around the cassette toilet, such as toilet paper and clothes. Before using the bathroom, it is essential to keep them away to avoid wetting them.

Cassette toilet manufacturers

By far the most relevant are toilets from Thetford and Dometic.

Thetford was originally founded in Michigan and already in 1971 established themselves in Europe. Nowadays it is a very popular brand both in the US and Europe. Today Thetford offers two main lines of cassette toilets: fixed and portable.

Dometic is a company with Swedish roots that was started as leisure appliances division of Electrolux in the late ’60s. Now it is an independent company offering a very wide range of products, but in this article, we have interest in their range of hygiene and cleaning solutions that offer RV toilets.

Thetford and Dometic fixed cassette toilets

There are three significant categories of Thetford and Dometic fixed cassette toilets based on the size of the unit, the capacity of the wastewater tank, and bowl material.

Bowls are coming in plastic or even in ceramic. Plastic is used in lightweight models, as ceramic bowls nearly double the weight of the toilet.

The capacity of wastewater tanks is from 17 to 19,3 liters for Thetford and from 16 to 19 liters for Dometic models.

Models are in a slightly different shape depending and dimensions. Below you can see a comparison table for the most popular models from both manufacturers.

ModelBowl materialFlush tankWastewater tankDimensions, mmWeight
Thetford C223-SPlasticCentral connection18 Liters495 x 365 x 5806.8 Kg
Thetford C223-CSPlasticCentral connection18 Liters534 x 394 x 5807.2 Kg
Thetford C223-CWPlastic9 Liters18 Liters750 x 417 x 6007.2 Kg
Thetford C262-CWECeramic8 Liters17,5 Liters750 x 417 x 60017.2 Kg
Thetford C262-CWEPlastic8 Liters17,5 Liters750 x 417 x 6038.1 Kg
Thetford C263-SCeramicCentral connection17,5 Liters488 X 341 X 60016.2 Kg
Thetford C263-SPlasticCentral connection17,5 Liters488 X 341 X 6007.1 Kg
Thetford C263-CSCeramicCentral connection17,5 Liters750 x 417 x 60017.1 Kg
Thetford C263-CSPlasticCentral connection17,5 Liters750 x 417 x 6038.0 Kg
Thetford C263-CSLCeramicCentral connection17,5 Liters540 X 417 X 60316.8 Kg
Thetford C263-CSLPlasticCentral connection17,5 Liters540 X 417 X 6037.7Kg
Thetford C402-X
Left / Right
Plastic15 Liters19,3 Liters512 x 670 x 4008.8 Kg
Thetford C403-X
Left / Right
PlasticCentral connection19,3 Liters512 x 670 x 4008.1 Kg
Dometic Saneo CSCeramicCentral connection16 Liters602 x 672 x 37713 kg
Dometic Saneo CWCeramic7 Liters16 Liters602 x 672 x 37713.5 kg
Dometic CTS 4110CeramicCentral connection19 Liters530 x 672 x 38212.50 kg
Dometic CTW 4110Ceramic7 Liters19 Liters530 x 672 x 38212.80 kg
Thetford and Dometic fixed cassette toilets size and capacity comparison table

Thetford and Dometic portable cassette toilets

Another popular line of Thetford products is portable cassette toilets offered under the brand name Porta Potti that already became a noun for this type of toilet. In fact, it is a similar cassette toilet that is fully portable and can be placed both inside or outside your camper or caravan.

The Net weight is only about 5 kilograms and the capacity of the waste-holding tank is up to 21 liters in the latest models.

Dometic offers two models with 9-liter and an 18-liter wastewater tank. The main advantage of Dometic portable toilets is their smaller size compared to Thetford Porta Potti.

ModelBowl materialFlush tankWastewater tankDimensions, mmWeight
Porta Potti 145Plastic15 Liters12 Liters330 x 383 x 4273.6 Kg
Porta Potti 165Plastic15 Liters21 Liters414 x 383 x 4273.8 Kg
Porta Potti 335Plastic10 Liters10 Liters313 x 342 x 3823.3 Kg
Porta Potti 345Plastic15 Liters12 Liters330 x 383 x 4273.8 Kg
Porta Potti 365Plastic15 Liters21 Liters414 x 383 x 4274.0 Kg
Porta Potti 565PPlastic15 Liters21 Liters448 x 388 x 4504.9 Kg
Porta Potti 565EPlastic15 Liters21 Liters448 x 388 x 4505.0 Kg
Dometic 972Plastic8 Liters9 Liters387 x 317 x 3334.68 kg
Dometic 976Plastic8 Liters18 Liters387 x 387 x 3334.99 kg
Thetford and Dometic portable cassette toilets size and capacity comparison table

Common Problems of Dometic and Thetford cassette toilet

The most common problems with these toilets are non-working flush, the smell coming from the holding compartment, leaking bowl.

We brought this question up and summarized it in a separate article. Please check out the list of common problems and their solutions.

If something is missing, just let us know by email or in the comment section.


The most convenient toilets people should opt into are cassette toilets. They can be used everywhere, even in the van. Anytime you travel by your vehicle, you need a private room for dumping waste.

These toilets are easy to use, maintain, and mostly odorless if used properly!

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