How to use portable toilets for campers and caravans (Porta Potti and cassette toilets)?

Few days ago I was impressed by the story of a friend: she would like to rent a camper for a holiday this year, but is concerned about the misadventures happened to some friends of her a year ago. This group had rented a camper, but they could not use the bathroom and I’m telling you why: nobody of them had never been in a camper before and they had no idea about how the bathroom works. At the time of delivery of the camper, they were told indeed that they should use an additive and that they could find it inside the camper. These unaware guys started to use the bathroom. They found the problem flushing the toilet: they were so disgusted that they decided to never use it again!

I suspect that the additive had been provided to them but they didn’t know that they should add it “by hand”! That’s why, despite we have already talked about this in a previous article about water management, I would like to deepen again how to use a chemical toilet in leisure vehicles like campers, caravans and motor-caravans.

There are three different types of toilet, with three different ways of loading and unloading.

1 – Porta Potti, the real portable toilet

For the older vehicles, typically the caravans like Martha, there is Porta Potti, the ultimate portable toilet. We use this one:

Porta Potti

2 – The cassette toilet

On the newer model vehicles, the WC is usually arranged in the bathroom and is not portable, so you can’t “dismantle” it. Here you can find an example of integrated WC with a discharge that is extracted from the side of the caravan:

Bagno Ela WC chimico scarico

3 – The integrated floor drain WC (or marine WC)

The WC without an extractable cassette is typical of the bigger vehicles. Its peculiarity is the giant tank, so you can discharge less than with the other two types. But you can discharge only in special areas (usually parking areas and, for campsites, into the waste areas for marine WCs), otherwise you have to prove yourself with discharge pipe and cassette, but it could end very badly.

How to use Porta Potti and/or cassette toilet?

I made some picture to our Porta Potti to explain you how to use it: it works in the same way of the cassette toilet.

First, you should know that it is composed by two distinct parts, and you can see them just looking it on the front:

Porta Potti

We are worried especially about the lower part…but we’ll learn how to face it with this article! I’m talking about the part that starts from the white handle downwards. Next to the white handle you can see a green marker: it’s not present in every Porta Potti, our one has it, and it’s the fill-up control. It’s mechanical, with a little float (DON’T ask WHERE it flows, you don’t want to know it) and turns into red when it’s time to discharge it.

Let’s start with the higher part, the easy one: also this part is a water tank, the clean water for discharge. In our Porta Potti the discharge works with a little mechanical pump driven by a piston:

Porta Potti

You can fill the tank with clean water just unscrewing the cap on the opposite side of the piston:

Porta Potti

It depends on the kind of your holidays, we usually don’t fill it so much because when we travel we prefer to keep it empty. Many people use chemical products also for this clean water. You can find a lot of specific products: we used this one for a long time but it’s expensive, so we often fill the tank only with clean water, using it like our home bathroom, just cleaning it!

To fill-up the discharge tank you can just use a canister or do like us: open the Porta Potti and take it under a water tap to fill it. Be careful, anyway, to avoid dish-washing sinks and try to be respectful towards other people: it’s the higher part of your bathroom. You know it is maniacally clean and disinfected, but other people DON’T.  Try always to think about what you would feel if someone else used the sink in which you want to fill up your WC and act accordingly.

Porta Potti is very easy to open: on the back you can find a switch and you have to pull it towards the centre:

Porta Potti  Porta Potti

You can see from the pictures that you must not force the switch, you have to pull it just enough to separate the two parts.

After having filled the higher tank, you have to prepare your Porta Potti before using it. Reassemble it: then you have just to add some water also in the lower part. How? It’s very easy, you have just to pull the white handle, as you can see in this picture:

Porta Potti

The handle gives you an access to the discharge tank. Now it is empty and clean, but if you want to use the bathroom you have to add some water and additive, your only friend in this dirty business, in the tank! We use one only brand, Thetford, and we buy it on Amazon, because every long-term camper told us it’s the best one (in particular, we use this one, that should be a little more ecological, or in desperate times this one, very useful and cheaper).

The right amount you have to use is written in the instructions, but it can be very variable: if you think to stay out just for one day, you have to use a little additive and a little water; if you think to stay out for more days or to not discharge it until is full, you have to use a different amount.

Anyway the additive is the key: if my friend’s friends at the beginning of this article had known this…they would have used their bathroom and their holiday would definitely have been better!

When using the bathroom, naturally, you have to open the handle: if you sense a smell when you open it, it means that you used too little additive or that it has not a good quality. A little advice about toilet paper: you don’t need to buy the super-expensive one made exactly for Porta Potti: you can buy the little, poor quality two-ply one, the kind you can find in a discount.

Let’s finally talk about THAT MOMENT: the discharge.

First: WHERE can I discharge my Porta Potti (or cassette toilet that, when extracted from the side of the camper, is exactly like ours)? Every campsite has the WC KIMIK, usually a bigger toilet bowl, or a normal toilet in the cheaper campsites, next to a water tap and a rinsing pipe. If there isn’t a WC KIMIK, you can use a normal toilet, but you will have to flush the toilet and/or wash. It can happen also that you use Porta Potti while you’re coming home, so you can easily discharge in your own bathroom, but you have to be careful and your WC has to be almost empty, or you will make a disaster! Discharging in a normal WC is an extreme solution, try to avoid it if you can.

So, close the white handle and open again in two parts your Porta Potti with the switch (or extract the cassette from the side of your vehicle). That’s how it looks like: can you recognize the white handle opening the black hole in which you have peed until now? Well, I warm you to let it well closed at this moment! For the discharge we will need the pipe on the right, the one whit the white cap.


Porta Potti

Once you arrive at WC KIMIK, you have to rotate the tip, unscrew the white tap and use it for discharging the WC! Ideally you could also push with the thumb that white round button that will let air in the tank, helping you to discharge everything without many problems.

Porta Potti

The water tap with the pipe that you usually find next to the WC KIMIK serves for rinsing your tank: put in some water, close the white cap, shake a little bit and empty again. Depending on how much it was full and how much additive you used, it will be enough rinsing a few times: if it’s not well-clean at the five-time rinsing, you probably made a mistake during the previous days!

What portable WC should you choose?

We never had doubt about the brand to choose: during the years, Porta Potti was found to be, also according to other long-time campers ‘opinions, the more resistant and reliable solution, even if one of the most expensive. But, my friends, let’s face it: we really want to risk that this object suddenly breaks, maybe inside our caravan, just to save 20 euros?

You can find different measures of Porta Potti: we chose the biggest one, both in terms of tank capacity and in terms of sitting. There are different models; we did not buy it online, because we wanted to see it live and choose it in a specific shop. On Thetford website you can also find a useful table of comparison between models. The 21 litres model, like ours, can be used even for three or maybe four days: we are just two people and we’re always around, we don’t spend all the time inside the camper, so we can easily use it for three days before discharging it. Somebody prefer to clean it every day: in this case maybe is useful and space-saving a smaller model, but suitable for your own “heights”! If you’re two metres high, maybe you should not choose the smaller model.

Please let us know if you’ve tried other products or other reliable portable WC and what is your experience!

Daniele Angelini

Daniele is a web designer, has created the site and takes care of its maintenance and all the technical and boring technical aspects. When he is not around for Italy, he works as an UX designer in a company that mainly deals with graphics and web development. He is passionate about sport fishing and camping trips as a child.

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