How to Use a Caravan Cassette Toilet Properly – Emptying and Chemicals


Hi, I’m Chris, I run Horton Common along with my father Robert.

Here at Horton Common while we offer fully serviced pitches we do not have on-site toilet facilities. Therefore all of our guests need to be familiar with how to use their caravan toilet cassette. Now, with this post, I’m not going to imply that emptying a toilet cassette is a pleasant experience. However, by following best practice and the use of suitable toilet chemicals and other products the experience of using and emptying a caravan toilet cassette does not have to be anywhere near as bad as some people imagine. Though its not a subject matter I particularly enjoy writing about. Therefore instead of multiple articles, I will make this post on how to use a caravan toilet cassette as comprehensive as possible.

How to Use a Caravan Toilet Cassette
If you are unsure or confused about how to use and empty a caravan toilet cassette the content below should answer your questions: Original images – thetford-europe.com

As you would imagine, I’ve had several conversations with our guests in the past about caravan toilet cassettes and using our CDP (Chemical Deposal Point) here at Horton Common. I’ve been asked about the various blue, green and pink toilet chemicals and guests have told me their experiences (politely) about using various products. However, I would never refer to my self as an expert on the subject, and who would want to! But I do have quite a few points of my own to make below. Though as with all of my posts I will be referencing the best content/videos I’ve found to provide you with everything you could ever need (or want) to know about using and emptying a caravan/motorhome toilet cassette.

Introduction – How to Use a Caravan Toilet Cassette

Sometimes speaking to new guests who are first-time caravanners they get concerned about how to properly use and empty a toilet cassette. I explain to them many of the points referenced below in a video I found produced by the Camping and Caravanning Club. When I get to see those guests again in the future after they have used and emptied the toilet cassette many times they generally state that the process was not as bad as they first thought. Now there are quite a few points to cover with regards to the proper use of a toilet cassette found in caravans and motorhomes. The video below provides a good starting point as a general introduction. However, below we’ll also go into a lot more detail on chemicals and answer some specific questions.

This is the first video I recommend that you watch on how to use, empty and maintain a cassette toilet found in caravans and motorhomes.

So the first thing I should probably point out that the brand who is synonymous with toilet cassettes is Thetford. There are a few other more niche brands out there. However, its more than likely that the cassette toilet in your caravan or motorhome is made by Thetford. As such, if you think your cassette toilet may be broken or just not working properly I have a post on Thetford toilet repairs and advice.

Thetford Caravan Toilet Cassette Lip Seal

If you’re not sure what a lip seal is, how to maintain it and when to replace it I would encourage you to read my post linked above on toilet repairs and advice: Image – Amazon

Now, if the Thetford cassette toilet in your caravan or motorhome does not look exactly like the one in the video above don’t worry. There are multiple different versions. However, they generally all operate in the same manner. While different toilets also have cassettes of different sizes the way you empty the cassette is universal. If I was to provide a couple of quick tips to emphasize the points from the video above it would be this. When emptying a toilet cassette always remember to press the air valve and empty slowly. As long as you remember these basic tips you can avoid any nasty surprises.

Horton Common CDP
I specifically designed and built our CDP here at Horton Common caravan site to make emptying a toilet cassette as easy as possible without any nasty surprises.

Swapping an Old Toilet Cassette for a New One

As stated in the video above, if you have purchased a used caravan or second-hand motorhome you can get a cassette replacement for the toilet if you wish. Just remember to purchase the right sized cassette to suit your specific Thetford toilet. Otherwise, the cassette will be either too small or too larger to fit within the locker housing. Alternatively, you could clean out the cassette with a suitable flushing chemical. I’ll discuss that more in the toilet chemicals section below.

Thetford C250 Caravan Toilet Cassette Fresh-up-Set

If you have purchased a second-hand caravan/motorhome and you want a new toilet cassette you order a ‘Fresh-Up-Set’ which also comes with a new toilet seat: Image – Amazon

Which are the Best Toilet Cassette Chemicals?

When using a toilet cassette in a caravan or motorhome, there is a range of chemicals to choose from. Some you must use and some are optional. Some are blue, some are green and some are pink. There are lots of different brands of these cassette toilet chemicals at different prices. Below I discuss my thoughts and the feedback I’ve received from our guests on the different toilet chemical brands. However, first I thought I would quickly summarise what each of the different coloured toilet chemicals is for.

  • Blue Toilet Chemical: Used within the toilet cassette to chemically break down the contents. Also helps to control odours. Thetford has its own blue toilet chemical product. However third party products are also available. Generally contains Formaldehyde.
  • Green Toilet Chemical: Sometimes also referred to as ‘Bio’, ‘Organic’ or ‘Formaldehyde-free’ for use within the toilet cassette as an alternative to blue toilet chemicals which contain Formaldehyde. Some caravans sites actually mandate the use of green Formaldehyde-free toilet chemicals.
  • Pink Toilet Chemical: This is not for use within the caravan toilet cassette. Its a fragrance additive for the flush tank. The use of this chemical is not strictly necessary. However, it can make the experience of using a cassette toilet more pleasant.
  • Cassette Toilet Cleaner: For periodic/annual cleaning of the toilet cassette. Degreases the interior of the cassette including the float valve.

Blue Toilet Chemicals – Are They All the Same?

So as shown the video above the blue toilet chemical is added before the cassette toilet is used and after each subsequent emptying. You should only add the blue chemical though the emptying port, and not through the slide valve. Pure concentrated blue toilet chemical can accelerate the ageing/denaturing of the rubber lip seal as part of the toilet slide valve. Thetford produces its own brand of blue toilet chemical called Aqua Kem Blue. Its available as a concentrated liquid in a 2-litre bottle. Thetford has now also started to offer Aqua Kem Blue with a Lavender scent. Alternatively, Thetford now offers Aqua Kem Blue as sachets. Some guests have stated they prefer the sachets for their convenience. However, you will be paying a premium for the convenience of the sachets.

Thetford Aqua Kem Blue Cassette Toilet Sachets

Thetford Aqua Kem Blue cassette toilet sachets are very convenient. However, on a per-use basis, they are the most expensive means to add the chemical to your caravan toilet cassette: Image – Amazon

Now, there are several other brands that offer concentrated blue toilet chemical for cassette toilets. Another well-established brand is Elsan. Per litre, you will generally be paying more for Thetford chemicals over other brands. For instance, you can get 4 litres of Elsan blue toilet chemical for a price similar to what you would pay for a 2-litre bottle of Thetford Aqua Kem Blue.

What about Budget Blue Toilet Chemicals?

Outside of the well-established brands such as Thetford and Elsan, there are several other companies selling their own versions of the blue toilet chemical. If you visit a caravan shop you will often see blue chemical bottles of unbranded or brands you are not familiar with. They will often be placed on a shelf next to offerings from Thetford and Elsan. If you do a quick comparison of the cost per litre you will realise that these products are often much cheaper.

Cheap Blue Chemical for Caravan Cassette Toilets

Cheaper/Budget alternatives to Thetford/Elsan vary in their effectiveness at breaking down the contents of toilet cassette: Image – Amazon

However, I’ve had reports from our guests over the years that while many of these unbranded blue chemical products seem a good deal at first, the results are sometimes a bit disappointing. The purpose of the chemical additive is two-fold, first to help break-down/dissolve the contents of the cassette and to control odours. In general, the reports I’ve been given is that while the odour control of these budgets products is very similar to that of Thetford/Elsan their performance at breaking down the contents is not equivalent. One guest told me that if they doubled the concentration of the budget blue chemical they were using it wasn’t an issue. However, they then worked out that by doubling the concentration of the budget liquid it ended up costing just as much as the Thetford product.

Budget/Cheap Blue Chemical for Caravan Cassette Toilets

Buying blue toilet chemical in bulk like this may appear to be a good deal. However, make sure you have actually tried that specific product before you purchase such a quantity: Image – Amazon

So while I would not discourage you from trying these cheaper/budget brands of blue toilet chemical I would encourage you to do the following. While the ‘buy 5 bottles’ at a time deals are very appealing, make sure you have actually tried that brand before ordering such a significant amount. You want to be happy with the performance of the product before you start buying it in bulk. After all, if the blue toilet chemical you choose does not properly break-down the contents of the cassette you will not be very happy when you come to try and empty it.

Green Toilet Chemicals – What’s The Difference?

Above in my summary of the different toilet chemicals, I noted that the blue chemicals for toilet cassettes often include Formaldehyde which is a toxic substance. Hence, when emptying a toilet cassette and adding blue chemical you really want to be wearing gloves for multiple reasons. Formaldehyde is a biocide, hence is kills microorganisms (bugs/germs). Now, the problem is on some caravan sites they have their guests emptying the cassettes into a septic tank which works on a biological decomposition process. Hence, the introduction of blue toilet chemical can kill off the bacteria which makes a septic tank effective at processing waste. Therefore, in some instances, caravan sites actually state the use of green toilet chemical which doesnt contain Formaldehyde as mandatory.

Thetford Aqua Kem Green Caravan Toilet Casette Sachets

Some caravan sites may require you to use the green ‘septic tank safe’ cassette toilet chemical apposed to the blue toilet chemical which contains Formaldehyde: Image – Amazon

As with the blue toilet chemicals referenced above, you have products offered by Thetford and Elsan and many other smaller brands and none branded products. From the reports I’ve heard from our guest, they have stated many of the same comments with green chemicals. The effectiveness of different products from different brands varies. Hence, the same advice applies. Only purchase small quantities of a specific brand to test to see if you are happy with how it performs before you start buying in bulk.

Does Green Toilet Chemical Work as Well as Blue?

Before we opened Horton Common in 2014 our family has been caravanning pretty much all my life. Hence, we already knew about the differences between blue and green toilet chemicals and have tried both. In our own experience, we have generally not found the green chemicals to be as effective at breaking down the content of the toilet cassette. This was why when we set up Horton Common we installed a cesspit tank and not a septic tank. As a cesspit tank is completely enclosed, hence it means I have to have a registered waste handler come and empty the tank a couple of times a year. However, it also means our guests can use either blue or green toilet chemicals. I’ve had several guests comment to me over the years they are happy they are free to use the blue toilet chemical, as they also generally find it performs better.

Elsan Green Organic Toilet Fluid for Caravan Cassette Toilets

Green/Organic/Bio toilet chemicals are currently more expensive compared to the blue/Formaldehyde version from the same brand: Image – Amazon

However, I also encourage our guests to try out green toilet chemicals to see if with further development they do become more effective. After all, I’d personally much prefer to use an organic toilet chemical over a Formaldehyde based product if they perform in a comparable manner. Furthermore, it would actually be cheaper to only purchase green chemical as it could be used on any caravan site you visited.

Pink Toilet Chemicals – Do You Need to Use Them?

Unlike the blue/green toilet chemicals, pink toilet chemicals are not used in the cassette itself. A dose of pink toilet chemical is added to the flush tank for the cassette toilet. This is usually done through a small locker hatch on the outside of the caravan/motorhome just above the main cassette locker door. As the pink chemical is not involved in breaking down the contents of the toilet cassette its not strictly necessary. However, the fragrance and the detergents used can help to keep the toilet bowl clean and it just makes it more pleasant to use. As a very small dosage is required a bottle of pink toilet fluid can last a pretty long time.

Thetford Aqua Rinse for Caravan Toilet Cassettes

Pink Thetford Auqa Rinse is available as a concentrate for the flush tank but also as a spray for the toilet bowl: Image – Amazon

As you would imagine you don’t just have the option of using Thetford Aqua Rise. You can get the pink toilet chemical from many other brands including Elsan. As the main job of the pink toilet fluid is an additional fragrance, cheaper alternatives may be a more viable choice compared to blue/green chemicals. As with Aqua Spray using the pink liquid as toilet bowl cleaner is one of the ‘safest’ options. You always need to remember the bowl on your cassette toilet is made from plastic. Therefore, some of the toilet cleaning chemicals you would use at home may actually damage/denature a plastic toilet bowl. Thetford does also produce a specific toilet bowl cleaner if you are looking for a stronger detergent than using Aqua Spray.

Toilet Cassette Cleaner – Do You Need To Use It?

Thetford recommends the use of their toilet cassette cleaner on a periodical basis. The duration of the periods between use will depend on how frequently you use your caravan/motorhome. With extensive/frequent use Thetford recommends the use of the cassette cleaner 2-3 times a year. Thetford promotes the degreasing qualities of their cleaner. It is important to remember that there is a float valve within the toilet cassette which indicates when its full. Therefore, without periodic tank cleaning, it is possible that the float value could be more prone to premature failure. However, unless you were a very frequent user of your caravan/motorhome I think using tank cleaner 2-3 times a year is excessive.

I would recommend using tank cleaner at least once per season: Image – Amazon

It is important not to confuse the Thetford Tank Cleaner with their Tank Freshener product. That product is for use on the greywater tank/Wastemaster. However, in my post on how to clean a Wastemaster, there are alternative solutions you could also consider. Thetford Tank Freshener while being a cheaper product does not contain the same detergents/degreasing agents as their Tank Cleaner. Therefore its less likely to produce similar cleaning results.

Toilet Paper – Do You Need to Use Quick Dissolve Paper?

Thetford also produces their own quick-dissolve toilet paper such as Aqua-Soft and they recommend its use with their toilet cassette. So you may be thinking, is there really going to be any real difference between using standard toilet paper and quick-dissolve toilet paper? Well first I would encourage you to watch the video below from Dan Trudgian on a test he conducted and then I’ll add in a couple of my own thoughts.

Dan Trudgian compares how standard toilet paper and quick-dissolve toilet paper compare in a pure water test.

So in the video above Dan conducted a pure water test with no toilet chemical present and the quick dissolve toilet paper does appear to breakdown easier/quicker. Now, personally we have never used specific quick-dissolve toilet paper in our toilet cassette and we have not had any issues. However, we also flush the toilet cassette thoroughly and periodically clean the tank. If as discussed above you were using a toilet chemical that didn’t perform particularly well and didn’t periodically thoroughly clean the cassette that may present more issues with using standard toilet paper. Hence, its really a personal preference. But if you are going to use standard toilet paper make sure to use enough toilet chemical and clean the tank as thoroughly as you can without being too vigorous and damaging the float valve.

What is a Happy Bowl Liner?

Now the Happy Bowl Liner is a product I was not familiar with until recently. I came across a video produced by the YouTuber Travelling K (Karen). She discusses her hesitations with ‘properly’ using her caravan cassette toilet. Someone recommended to her the use of the Happy Bowl Liner. Her concerns around using the toilet were around the poor performance of the manual flush on her toilet cassette. However, it should be noted the electronic flushes on more modern Thetford toilets perform much better. I actually suspect that Karen’s manual flush is faulty and not generating sufficient suction. Anyway I’ve included Karen’s video below if you’re interested.

Karen discusses how she is more comfortable using her caravan cassette toilet with the aid of Happy Bowl Liners.

Conclusions on How to Use a Cassette Toilet

If you were unsure on how to properly use a cassette toilet in a caravan, motorhome or campervan I hope this post has answered your key questions. Obviously choosing the best chemicals for you will partly depend on your budget but also on the specific campsite you visit. While on some caravan sites like here at Horton Common you can use either blue/green toilet chemicals other sites you may be requested to use only the green toilet chemicals. From the feedback I’ve received from our guests and my own experience, they are not quite as effective as the blue chemicals. However, that will hopefully change in the future, as nobody really wants to use a product which contains Formaldehyde. As I’ve referenced above, I have this post on how to maintain and fix your Thetford toilet if your experiencing issues.

Thanks for reading. Now that you are fully clued up on how to use a cassette toilet I hope you also consider coming to see us at Horton Common caravan site. You will get to experience our fully serviced pitches and amazing views over the Staffordshire Moorlands and Peak District National Park. 🙂

Chris - Site Manager

Hi, I’m Chris, along with my father Robert we operate and maintain Horton Common Caravan Site. Located in the Staffordshire Moorlands Horton Common benefits from expansive views over the Peak District National Park. Horton Common features five hard standing fully serviced pitches for caravans and motorhomes.

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