What is a cassette toilet? A cassette toilet is a permanent toilet with a portable black tank. This toilet system has been widely used in European RVs for decades. Now it’s making a splash in the North American market. Search for cassette toilet and you’ll find countless forum threads on the topic. We became aware of this “new to us” toilet system when Hymer introduced the Aktiv Class B camper van to the North American market.

The Cassette Toilet

cassette toilet system thetford c260

Why Use it?

The portable holding tank is the main benefit of a cassette toilet. Instead of the traditional holding tank, the portable tank can be removed and dumped in public restrooms or at dump stations. This system is great when camping in places without a dump station. Instead of having to drive to a nearby dump station, we can remove the cassette and walk it to the bathroom.

Cassette Toilet Manufacturer

The most well known manufacturer of cassette toilet systems is Thetford. Their line of cassette toilets are used in RVs and boats. In North America, Thetford offers two holding tank sizes: 4.5 gallons or 5.1 gallons. With water weighing in at 8.34 pounds per gallon, a full waste tank can weigh more than 40 pounds. That can be quite a heavy load for one person to carry.

One concern with cassette toilets is the size of the holding tank. Cassette toilets have a significantly smaller holding tank compared to its permanent counter part. For example, there was a built-in 40 gallon waste tank in our old RV. We could boondock 10-12 days before breaking camp to find a dump station (How to Dump RV Tanks). However, we were limited to dump stations in the old RV. With the cassette toilet, we can dump at a station or a public bathroom.

Different From a Portable Toilet

The cassette toilet is not the same as a portable toilet. The difference is the cassette toilet is permanently attached to the RV or boat. However, both toilet systems have a portable waste tank that can be removed for dumping.

How It Works

The cassette toilet is very simple to use. For the purpose of this post, we will focus on the Thetford C-260 model, the cassette toilet system in our Class B RV. The basic function of the cassette toilet system is the same. There are three main components: toilet, portable waste tank, and water source.

The toilet is permanently secured to the outer wall of the driver’s side of the RV. The toilet bowl turns up to 180 degrees on its base to maximize the small space. There is a handle along the outside of the toilet bowl that will open and close the valve to the waste holding tank below. Once the valve is open, push the flush button. Close the valve after the water has drained.

The flush button is installed on the wall of the bathroom above the toilet. The water is connected to RV’s central water tank. Next to the flush button is the waste tank level indicator. A red light indicates when the waste tank is full. There are models that have their own water holding tank for flushing.

The portable waste tank sits below the toilet. It can be accessed from a door on the driver’s side. There is a lock on the door to prevent theft of the portable waste tank.

How to Dump Cassette Toilet

To dump the waste tank, make sure the valve blade handle is in the closed position. Open the cassette door outside, pull up on the safety catch to pull out the tank. Carry or roll the cassette (it has wheels and an extendable handle) to a dump station or bathroom. Remove the spout on the tank and lift it over the dump hole. Once the spout is pointing downwards, press the vent button. Hold the tank over the dump hole until all the waste is emptied. Pour water into the waste tank, gently swish it around and empty the tank again until the liquid is clear.

Our Rules for the Cassette Toilet

Note: these are our personal rules for the cassette toilet. Develop rules and routines that work best for your needs.

1. No Number Two. The cassette toilet is designed for number one and number two. To save tank space and for an easier rinse, we only use it for number one. One rinse is all that’s required to clean the tank. There are public restroom options to take care of number two.

2. Toilet Paper In the Trash. Another way to save tank space.

3. Dump Frequently. Since I volunteered to dump for one year, I dump every two to three days regardless of how full the tank is. Frequent dumps keep unpleasant odors to a minimum.

4. Chemical Free. To keep the RV from smelling like a portable bathroom, we choose not to use chemicals. By following rules number 1 – 3, we don’t need the chemicals.

5. Keep the Lid Down. Avoid the “splash” by making sure the lid is down before opening the valve blade. Pressure can build in the holding tank that can result in splashing. You don’t want to end up in the splash zone!

6. Cleanliness is Next to Godliness. Prevent unpleasant odors by cleaning the toilet and tanks regularly.

7. An Ounce of Prevention is Worth a Pound of Cure. Read the manual and follow the maintenance recommendations. The valve blade and seal need regular maintenance especially with frequent use.

What we think after 60 consecutive days of use. The cassette toilet is extremely easy to use as long as we follow the rules. The portable waste holding tank is simple to operate and can be easily replaced unlike a traditional holding tank. The system also makes dumping more convenient and we have more options.


If you enjoyed this post, check out Composting Toilets for RVs.
If you want a good laugh, read about how we made out with our composting bucket toilet.

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