Do Cassette Toilets Stink?

Cassette toiling sitting in van floor

If you are considering installing a toilet in your RV or van, you have probably already looked into cassette toilets. These types of toilets have mixed reviews and some people love them while others hate them. There is a certain amount of ickiness associated with having a toilet like this inside a vehicle. Depending on what you use it for, it could become quite messy.

A cassette toilet does not stink as long as you use it for number one only. Using it for number two might create a problem unless you intend to dump it shortly after using it. If you add chemical treatments to the toilet and dump it often, you will probably never notice any unpleasant odors.

Problems can arise when you use the toilet for both liquids and solids. Once you start dropping deuces into it, you could be looking at a real, stinky mess. Many people who use a cassette toilet only use it for number one and keep it as an emergency solution for other needs that may arise.

I have one in my van and I consider it a necessity. I use it all the time for number one and have never had a problem with it. I keep it cleaned out and dumped regularly so I never let it build up or give it time to develop into a stinky problem.

I always use chemicals or vinegar in it so it generally has a fresh, chemical smell that comes from it when you open it up to dump it. When it is sitting unused in the van, I have never noticed a smell coming from it.

In case of emergency, if I were to use it for something other than peeing, which I have done a time or two, I make sure to dump it as soon as possible. You never want to leave solids inside the tank to marinate.

If you use it for liquids and solids, be sure that you have a plan to dump it as soon as possible. After it has been dumped, be sure to clean it out well so that nothing is left inside.

I have heard horror stories from people who have used it for both during a longer period of time. Once it was time to dump, it was an absolute nightmare. The smell can become disgusting and make you never want to use the toilet again.

These are actually great toilets and can serve you well as long as you follow a few simple guidelines.

5 Simple Ways To Keep A Cassette Toilet Smelling Fresh

1) Use Chemicals

Dropping chemicals into cassette toilet

One proactive step that you can take to ensure that your toilet doesn’t become a stinky mess is to use chemicals designed for this type of use. These types of chemicals break down the waste and tissue while also adding a fresher smell to the waste tank of the cassette toilet.

These come in handy drop-in packets similar to what you would find for use in a dishwasher. You just drop them in the bottom of the tank and then the wastewater that falls into the tank will mix with the packet. This type of solution is also available as a liquid that you can pour into the tank.

The liquid is great for using in small amounts when you are just going on a short trip. Rather than wasting a whole drop-in packet, you can use a small amount of liquid and this will do the trick.

I often use a small amount of liquid chemical when I am going on an overnight stay or a few days away. If I am going on a trip where my waste tank will go a little longer between dumps, I will use a drop-in packet.

Both of these types of chemicals are biodegradable and can be emptied in standard sewage systems. They can also be dumped in campground dump stations and other dump stations that can be found in other places.

2) Dump & Clean Often

When using a cassette toilet, you will want to dump it and clean it as often as you possibly can. Allowing the cassette toilet to become filled with waste is a good way to create a stinky problem within your RV. You can avoid this by simply dumping the cassette toilet every chance that you get.

I try to dump my cassette toilet at least every day when I am out on the road on a trip. It isn’t always possible but it is a good idea to plan to do this as much as you possibly can. Some people allow their cassette toilet to fill up during an entire trip and then empty it after a week’s worth of using it.

This is a disaster waiting to happen. I wouldn’t suggest allowing your toilet to fill up more than three days at the most. Any more than this and you are likely going to have a smelly toilet.

It should also be noted that anytime you dump your toilet, you should take the time to clean it. This means that you should run freshwater in the waste tank and swish it around and dump it. Do this multiple times until the rinse water is coming out clear.

You don’t want to have colored water or water with chunks still coming out of the holding tank. Be sure that everything is removed from the cassette toilet before you call it complete.

It’s also good to add a little white vinegar to the rinse water as you are swishing it around. This works great but you can also choose to use a commercial cleaner as well. I prefer to use white distilled vinegar because it is a cheap option and does a great job.

3) Don’t Let It Get Too Full

Cassette toilet fill level gauge

As mentioned in the prior tip, dumping your toilet regularly will help you avoid a toilet that is too full. Be sure you plan ahead and do not allow your toilet to get too full. You don’t want to be in a location where you cannot dump your cassette toilet waste tank even though it is getting to a higher level.

It’s a good rule of thumb to not allow your toilet to get more than half full. Even though in an emergency you might allow it to go more than this, in normal situations, it’s good to adhere to this.

Many cassette toilets have a gauge that lets you know whether they are full or close to being full. Many of these aren’t very accurate or only give a general idea so you will need to pay close attention.

One good way to make sure that you do not overfill your waste tank is to not fill up the entire freshwater tank. If you keep the freshwater tank half-filled, you can make it a point to empty the waste holding tank once the freshwater tank is near empty.

The freshwater tank is almost always a larger capacity than the wastewater tank so if you fill the freshwater tank to its full level, you will still have fresh water available even after the waste holding tank is full. Avoid this mistake by not filling the freshwater tank up to its maximum capacity.

You can always add additional water to the freshwater tank as needed if you can not dump it at the exact moment that your freshwater tank runs dry.

4) Don’t Mix Liquids & Solids

Having a toilet in your RV doesn’t mean that it is to be treated like your home toilet. Of course, you can choose to do this if you wish but I will warn you that mixing liquids and solids is a recipe for disaster. Unless you are going to dump the holding tank right after you dump your bowels, I would leave the cassette toilet for number one only.

Mixing the two can create a mess that will likely become a gross situation to deal with. It’s not that you will smell it within your RV or van but the problem will occur when you go to dump the holding tank. If you leave the waste to marinate for a length of time, the surprise you will find when emptying the holding tank will not be very pleasant.

Although I have used my cassette toilet for both, I typically only use it for number one. Peeing in the cassette toilet does not pose any problem and isn’t even gross when emptying it. Of course, this is assuming that you empty it regularly.

However, once you begin to do both and especially if multiple people are using it, this can get pretty gross.

It’s best to have another solution for number two and possibly even depend on public restrooms. If you are boondocking, you can take a shovel and head out into the wild to relieve yourself the natural way.

5) Keep Water In The Bowl

Water standing in cassette toilet bowl

In order to avoid any smells coming out of the holding tank, you should always keep a small amount of water in the toilet bowl. This will help to seal the tank and not allow odors to pass through.

This is similar to the way a P-trap works in a plumbing system. By allowing water to stand in the P-trap, no gas odors can come through and enter into the living area.

When you are not using the toilet, make sure you leave a little bit of water in the bottom of the bowl to create this effect. Of course, you will need to make sure your toilet is secured and level when you are driving. You don’t want the water to be splashing out as you are driving.

You don’t have to put a lot of water in the bowl, just a small amount will do the trick.


Talking about toilets can be a nasty subject that many people avoid. However, it’s a fact of life and we all need to have a way to relieve ourselves. All humans do it so there is no need to shy away from the discussion.

Having a cassette toilet in your van or RV can be a very convenient way for you to make sure you always have a way to use the restroom.

Many people do not like to have toilets like this and prefer to only use public facilities. This may depend upon where you are currently at in life. Younger people may be fine with using public facilities but more mature folks will appreciate the convenience of having a private toilet at their disposal.

Cassette toilets are the best option for the money. They don’t cost a lot but they offer a convenient and reliable solution. There are lots of different options and capacities that will work for all types of people and their needs.

A cassette toilet was my first type of toilet in my camper van and it’s the one that I have stuck with. I love it and wouldn’t want to be without it. I find it to be very handy and no big deal to maintain.

It isn’t as dirty of a job as you might imagine as long as you stick with the tips that I mentioned in the article above. You will be able to use it and not have to worry about the toilet becoming a smelly problem within your living space.

Dan Collins

I consider myself an outdoor enthusiast. I love to travel and go to places that most people don't get a chance to go. I want to see it all and live life to the fullest while I'm alive. My camper van is helping me to do just that. I write about my experiences to help inspire others to do the same.

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