Skip to Content

Cassette Toilets Explained: What They Are and How They Work

RVs come in many shapes, sizes, and price ranges. But the great equalizer among them all is the trip to the dump station to empty a rig’s waste tanks. That is unless you use cassette toilets. With these updated commodes in your RV, you might be able to skip the hassle and long lines of a dump station altogether! Read on to learn more.

What Is a Cassette Toilet?

Traditionally, an RV toilet flushes down into the black tank secured to your RV’s underbody. When your black tank is full, you empty the contents at a dump station. 

With a cassette toilet, instead of the waste going into your black tank, it enters a small, portable waste tank. You can remove this waste tank, which rolls on wheels like a suitcase, and dump it at a public restroom or dump station. 

inside rv cassette toilet from above
Cassette Toilet in a Class B Adria Matrix motorhome

As you can imagine, emptying your portable tank can be a little more uncomfortable than emptying your black tank, so it’s not for everyone. But it can be the right option for RVers who often go off the grid. 

How Does It Work? 

The concept of a cassette toilet is similar to a portable one, but it’s permanently affixed to your RV. On the surface, it looks and acts much like a normal toilet.

You first open the toilet valve door, do your business, flush, and then close the valve. The major difference is in the holding tank size and how you dump it.

Pro Tip: If you’re new to RV toilets in general, check out our guide to the main RV toilet types.

Cassette Toilet Review - What Is it? How Do You Use it? Where Do You Dump It?

How Do You Dump a Cassette Toilet?

Some tanks for your cassette toilet have a sensor that tells you when it reaches capacity. Otherwise, it is very easy (albeit unpleasant) to look into the cassette from the toilet. You may also get clues from the potency of the smell. Generally, regularly used cassette tanks need to be dumped every couple of days.

At that point, it’s time to empty it. You’ll have to do this much more often than you would a black tank, but it’s usually more convenient to do so. 

To dump a cassette toilet, you first make sure the toilet bowl is empty. After you’ve emptied the toilet bowl and turned the valve blade handle to closed, you’re ready to remove the holding tank. Typically, there will be a side access panel on your RV’s exterior where you can slide it out. Open the access panel and release the latch holding the cassette tank in place. The tank should slide out easily, and then you can tank it to your dumping location.

cassette toilet from outside rv camper motorhome
Removing a cassette toilet holding tank.

Most have a handle and rollers so that you can pull it behind you to the bathroom or dump station. If yours doesn’t, and you have to carry it, make sure you empty it before it gets too heavy!

However, this does make it convenient for dumping in a variety of locations. Normal RV dump stations are available to you, but so are regular toilets and outhouses.

Pro Tip: Check out our favorite places to dump our RV waste tanks.

cassette toilet tanks being wheeled to the dump location
Most cassette tanks have wheels and a handle to cart them to the dump location.

When you’re ready to release the contents, open the dump spout on the tank and place it over the toilet or dump hole. Then, let gravity do its work. If you’re at a dump station, just let the waste flow. But if you’re using a regular toilet facility, you might flush two or three times during the process to prevent clogs or overflows. 

Many portable tanks have a pressure release button that essentially helps push the waste out of the spout. Once you’ve lowered the spout into the hole or toilet, you can press this button to release the pressure–be very careful not to bump it before, or you’ll have a mess! 

When all the waste has left the cassette, it’s time to clean it out. Pour some water into the tank and shake or swish it before emptying it again.

You’ll probably have to do this several times to get it fully clean, so wait until the water runs clear before replacing the tank. Also, this is a good time to add a tank cleaner if you’re so inclined. 

dumping a cassette toilet
Dumping a cassette toilet.

Cassette Toilet Holding Tank Size

Cassette toilet holding tanks are small, making them perfect for Class B RVs, small truck campers, and similar vehicles with little storage space. The tank size will vary depending on what you buy, but it’s usually around five gallons. 

When you compare that to a black tank that holds between 15 and 90 gallons, it’s clear how different this lavatory is. You’ll have to dump your portable tank every two to five days, depending on how many people are using it regularly. 

Difference Between a Cassette Toilet and a Portable Camping Toilet

The primary difference between the two is that the cassette toilet isn’t really portable. It simply has a portable waste tank. It’s affixed to your RV, so you can’t take it anywhere you want. 

A portable camping toilet, on the other hand, is mobile in every sense of the word. You can take it pretty much anywhere you can carry it. When it’s time to empty a portable toilet, you’ll typically remove the toilet seat and take the bottom to the restroom or dump station to empty it. 

The dry flush toilet is another completely portable option that uses a bag-like liner to collect waste. When the bag is full, it gets removed and tossed in the trash. The other difference here is that the cassette toilet uses water to flush, while portable toilet options like the dry flush are waterless.

Benefits of Cassette Toilets

The number one benefit of cassette toilets is their size. Many small RVs would not have toilets if it weren’t for this option. 

The second reason that RVers might want this commode is its portability. If you like camping off the grid, you don’t need to be near a dump station to empty it. You can drive it to the nearest restroom and empty it, freeing you to go wherever you wish. Plus, it only takes a few minutes. 

They also have fewer parts, and you won’t have the hassle of handling, cleaning, and storing a sewer hose. The days of keeping sensors clean in a giant black tank are over, and because you can clean it every time you empty it, you’re less likely to have a smell in the RV. 

Cassette toilets are common in Class B RVs.

Cassette Toilet Use and Maintenance Tips 

There are some limitations to using a cassette toilet. While you can theoretically use this toilet like any other, you probably should avoid going “number two” in there as much as possible. It’s great for emergencies, but doing it too often can lead to clogs and make dumping the tank difficult. 

Additionally, you shouldn’t put toilet paper in the toilet. It’s better to throw it away since it takes up space and doesn’t dissolve as quickly in the portable tank. 

To keep your toilet in tip-top condition, dump it frequently. If you’re traveling by yourself, dump it at least every four or five days and every two or three days if you’re with a group. You might find that you need to empty it sooner because it’s too heavy. 

Cleaning your tank is as simple as pouring about half a cup of distilled white vinegar in there with some water after you empty it. Swishing that solution around regularly will reduce your chemical usage. Clean your toilet regularly to avoid odors as well.

These things might seem inconvenient in the moment, but doing them every time will keep your small throne functioning and reduce mishaps. Your toilet is the very last thing you want to malfunction when you’re boondocking in the middle of nowhere. 

Is It Right for You?

When looking at the use and benefits of a cassette toilet, it’s pretty easy to see the cons. It’s probably not a suitable option for a family of four or more who like to travel off the grid. It can also be a hassle to dump it regularly. 

However, it can be a useful thing if you regularly camp near vault toilets or public restrooms. You can use it when you need it most and use the other toilets when you don’t. In the end, a cassette toilet is much better than no toilet at all! 

If you think a cassette toilet is right for you, check out the best cassette toilets available and how to replace or install them.

Become A Mortons On The Move Insider

Join 15,000+ other adventurers to receive educating, entertaining, and inspiring articles about RV Travel Destinations, RV Gear, and Off-Grid Living to jump-start your adventures today!

About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

About Us

Sharing is caring!

Tom Brian

Friday 19th of November 2021

If your RV is small or you don't have a black tank, the cassette toilet is a preferable option. The waste tank capacity of a cassette toilet is 5 gallons, more or less, depending on the model.


Sunday 11th of April 2021

Contrary to your experience, we don’t have a problem at all using our cassette for #2 and find that it works very well with both toilet paper and wipes. While it will go three days or so for two people, we’re found that it best to take the time and dump it once a day....that way you never have any emergencies when you can’t find a flush toilet, pit toilet, or dump station for a couple of days.

And friends of our who have composting toilets their rigs rave about them. So check out the composters!