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5 Best Cassette Toilets and Replacement Guide

The best cassette toilets should make your RVing lifestyle easy. These toilets are popular in small RVs and are known for their versatility when it comes to dumping locations. But like all things RV-related, they can wear out and require repair or even replacement. Keep reading to learn how to replace a cassette toilet and what the best cassette toilet options are.

Let’s get started! 

What Is a Cassette Toilet?

A cassette toilet has a removable waste tank. When it’s at capacity, you’ll remove and empty it into a plumbed toilet or sewage system. Most cassette toilets have a door from the exterior of an RV to access the waste tank, so you don’t have to carry it indoors. 

Cassette toilets are alternatives to large waste-holding tanks in your RV or cabin. There are portable versions or more permanent models. You can transport portable cassettes from your RV to the campsite and home by using convenient suitcase-style wheels and extendable handles. The more permanent models hook up to fresh water and require wiring if you have an electric flush. 

Dirty Secrets of Cassette Toilets • RV & CAMPER VAN Realities

How Long Do Cassette Toilets Last? 

The best cassette toilet holding tanks are five-gallons and can last up to 50 (small) flushes. You may have to dump the waste tank sooner, depending on the amount of waste. But if there’s only urine in your tank, 50 flushes is a reasonable estimate. 

However, we recommend emptying your cassette tank before it’s at capacity. The tank will get very heavy otherwise due to the volume of liquid inside. Five gallons times about 8 pounds per gallon of water means the cassette could have upwards of 40 pounds of liquid inside it. We know from experience that’s not fun to have to haul around or lift to dump!

From a durability standpoint, we would hope that a cassette toilet should reasonably last for most of the life of the camper. This, however, largely depends on the maintenance, cleaning, and care of the toilet, as well as how often it is used.

Pro Tip: When you gotta go, you gotta go. Ditch the porcelain throne and try out one of these 5 Best Off-Grid Toilet Options to Save Water and Manage Waste instead.

Common Problems With Cassette Toilets

Even the best cassette toilets can have occasional problems. Common problems include seal loosening, flushes not working, overflowing, and clogging.

Problems with Cassette Toilet Seals

One of the most common issues is seal loosening. Perform regular maintenance on your toilet to prevent a significant issue in this area, or you may have rather unpleasant leaks into your cassette cabinet or even into the RV. This is one of the things we dislike most about cassette toilets.

Cassette Flush Not Working

Another problem area to watch for is the flush not working If the flush is not working, troubleshoot it by first checking if you need to either clean or replace a fuse. The fuse is often located at the back of the cassette cabinet accessed from outside. You can determine if the fuse needs replacing by visually inspecting it or testing it with a multimeter.

If the fuse isn’t the issue, then it might have something to do with the flush control panel. Carefully remove the flush mechanism panel and check the connections for corrosion. You can also remove and replace the switch connection a few times to reestablish good contacts. If that doesn’t work, you can go back to your handy multimeter for a voltage test to make sure you’re getting power in and out. The video below does a pretty good job showing how this works:

Thetford cassette toilet not flushing, how to fix. Thetford toilet

If none of these fix it, you can check the pump for functionality. This pump location will vary depending on your model. The pump may need to be repaired or replaced.

Indicator Light Stops Working

Many indicators use magnets to sense the level of liquid in the cassette. If your cassette indicator isn’t working, you may have lost a magnet or you may have a faulty circuit board. At the back of your cassette cabinet, you’ll see a little circuit board with wires going to it. This little circuit board is called the reed switch. If you remove the circuit board, you can test for continuity with your handy multimeter to see if it is working. Set a magnet on the reed switch (red bar) and test for continuity.

You can also use this method to check and see if the internal magnet in your cassette tank is still there or if it got flushed away. While holding the multimeter on the two sides of the switch, move it around the end of the cassette tank where your magnet should be. The video below shows how this can be done:

Fixing a Thetford C250 Cassette Indicator

Also, check the connections on the circuit board for corrosion and clean them if necessary. The connections may have corroded away.

Overflow and Clogging

To prevent overflow, we recommend keeping a diligent eye on your tank sensor (if it’s working), which is often located on the flush mechanism. Empty your cassette soon after the indicator turns red, or the next time you go might be a disgusting surprise.

Clogging of cassette toilets is rather uncommon, but the “poo pyramids” of regular black tanks can occur in the right circumstances. Having too much solids-to-liquids ratio may require more frequent dumping as well as difficulty getting it to empty. This can result from a broken cassette flush, where less water is contributed to keep everything flowing.

To help avoid this, we recommend putting your toilet paper in a waste bin and using the toilet primarily for urine. Utilizing public restrooms when you can for your “number two” will prevent clogging and reduce dumping frequency.

RV cassette toilet
Cassette toilets might look like traditional RV toilets. However, they have portable waste tanks instead of black tanks.

Reasons to Upgrade or Replace Your Cassette Toilet

If your cassette toilet is constantly malfunctioning, it’s likely time to replace it. You can replace it with a different toilet. However, before you disassemble the entire toilet, check if you can only replace the waste tank. Rather than doing a significant change, if your toilet is having issues, you may be able to get away with only replacing the tank. 

Reasons to upgrade your toilet can vary. Maybe your toilet is old and stained, and you’re ready for something new.

Some people upgrade to a composting toilet after using a cassette toilet. A composting toilet is a more considerable investment but an upgrade compared to frequently emptying the cassette toilet.

Pro Tip: Before you rule out a composting toilet, make sure you know the facts. Here are 5 Composting Toilet Myths You Need to Ignore.

How to Replace Your Cassette Toilet

Replacing your cassette toilet can be easy if you’re the person who installed it, like in a van conversion build. You should know where all the screws, wires, and plumbing are. 

However, many cassette toilets come already installed by the manufacturer, and sometimes replacing a cassette model is a more extensive project. Do your research on the particular model that you have in your camper or van. There are YouTube videos demonstrating how to remove one from an RV. 

Installing a COMPOSTING Toilet in a Motorhome | DAY 3 #vanlife

Once you remove the toilet, measure your space for the new one. Ensure you have the freshwater plumbing and wiring in the correct spot for the new product. From there, follow the directions for installing the toilet you purchased.

In addition, if you have a portable toilet, swapping it out for a new model is straightforward. 

Pro Tip: Portable toilets are a convenient solution for various types of camping. Find out What They Are and How They Work.

Compatibility Concerns for Replacing Your Cassette Toilet

If your current toilet is a portable model, you’ll likely want to replace it with another portable toilet. In this case, you’ll simply need to consider the size of the toilet when thinking about compatibility.

However, if you’re replacing a permanent toilet, you’ll need to consider whether or not your unit is connected to your RV’s fresh tank. Some cassette toilets house their own fresh water while others are plumbed directly to the RV. If your current toilet is connected to your RV’s fresh tank, you’ll want to replace it with one that has the same functionality.

Also, keep in mind that some cassette models feature an electric flush. This means you’ll need to make sure your RV bathroom is wired accordingly. Otherwise, you’ll want to choose a manual flushing toilet.

Replacing a Standard RV Toilet With a Cassette Toilet

Some people may want to replace an existing gravity-fed toilet with a cassette toilet. In this case, you will have to make some serious modifications to the plumbing and vent tubes, as well as install the cassette cabinet access on the outside of your camper. Consider your layout before opting for this choice.

Installing a Cassette Toilet in a Truck Camper

5 Best Cassette Toilets for Upgrading Your RV Toilet 

RV toilets can be a pain, especially when you have to empty the black tank or when there’s a clog. Upgrading to a cassette toilet can be a game changer. Let’s examine the five best portable cassette toilets on the market.

1. Thetford 32811 Cassette Toilet

About: The Thetford 32811 Cassette Toilet is a bench-style toilet that weighs in at just 22.45 pounds and is 29 x 17.25 x 21.75 inches. For easy dumping, the 5.1-gallon holding tank has wheels and a retractable handle, similar to a suitcase. It’s also important to note this cassette empties from the right-hand side.

Special Features: This Thetford toilet features an electric push-button flush and an LED display that indicates when the waste tank is full.

2. Thetford C223-CS

About: The Thetford C223-CS is perfect for tight spaces with its rotating toilet bowl that allows you to use the toilet from different angles. The waste tank has a handle and wheels, plus a no-splash pour spout for a cleaner dumping experience. You’ll appreciate the generously sized waste tank which holds 4.75 gallons.

Special Features: This toilet connects directly to your RV’s fresh water tank and has an electric flush system.

3. Dometic CTS 4110

About: If you’re looking for a sturdy, scratch-resistant toilet, the Dometic CTS 4110 is a solid choice with its ceramic inlay. It also features a swivel seat that rotates 90 degrees. The waste tank holds 5 gallons.

Special Features: The Dometic CTS 4110 has a high-powered flush and a built-in control panel with a tank level indicator.

4. SereneLife Outdoor Portable Toilet

About: The SereneLife Outdoor Portable Toilet includes directions for use on the toilet seat and a handy toiletry bag. It has a 5.3-gallon waste tank and a level indicator, so you know when to empty it. This portable cassette toilet is lightweight and ideal for camping.

SereneLife Portable Toilet with Carry Bag –...
  • CONVENIENT, COMPACT, AND PORTABLE – The SereneLife portable...
  • LARGE CAPACITY OF UP TO 120 FLUSHES – Our extra-large tank of...
  • LEAK-PROOF AND ODORLESS DESIGN – To prevent unnecessary messes...

Special Features: The toilet has a rotating emptying spout so you can quickly empty it, and it has a double-sealed drain valve to keep out the odor. 

5. Zimmer Portable Cassette Toilet

About: Zimmer’s Portable Cassette Toilet has a 5-gallon waste tank and a 3-gallon fresh water tank. It has top-tier toilet tech with a water-tight seal to keep odor out of your RV and prevent leaks from the toilet. 

Portable Toilet Camping Porta Potty - 5 Gallon...
  • FULL-SIZED CONVENIENCE - This travel toilet is the answer for...
  • 8-GALLON HOLD - You'll get a 3-gallon freshwater holding tank...
  • EASY TO USE - When your portable bathroom is ready to be...

Special Features: This toilet is made of high-density polyurethane to withstand frequent use and transport. 

RV cassette toilet
Make sure you clean your cassette toilet and its waste tank to prolong its life.

Cassette Toilet Care Tips

You can prolong the life of a cassette toilet with proper cleaning techniques. Use a toilet cleaner to maintain the toilet but only one with a soft brush. A stiff brush can cause scratches that will collect dirt. We also recommend cleaning the outside of the toilet regularly with a camp cloth. 

Be sure to rinse the waste tank with water every time you dump it. Swish the water around for a minute in the tank to ensure you’re getting all the edges. 

Upgrade Your RV With a Brand New Cassette Toilet

Are you ready to upgrade your RV with one of the best cassette toilets on our list? One of these can improve the RV lifestyle. You can be off-grid longer without running to a dump station frequently since you can dump the waste from a cassette tank into a regular public toilet or porta-potty. 

Cassette toilets are excellent options for people who travel frequently. They’re lightweight and easy to manage. You won’t have to worry about a full black tank weighing you down when you hit the road. 

Removing a cassette toilet waste tank

Not sure if a cassette toilet is the right choice for your RV? Check out our Practical Guide to the 6 RV Toilet Types to find one that suits your lifestyle.

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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.

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