Bought a used caravan or motorhome?
Start with the bathroom
You’ve just bought a used caravan or motorhome and are probably eager to take it out on the road.
And you’re not alone. Across Europe, the number of second-hand leisure vehicles keeps growing. Between 2024 and 2025, the used vehicle market increased by 2.2%, reaching around 6.7 million vehicles (source: European Caravan Federation). More travellers are choosing pre-owned caravans or motorhomes to start their journey.
Before you take to the road, there’s one place that deserves your attention first: the bathroom. It might not be the most glamorous part of your setup, but it’s the one that makes the biggest difference to your comfort. With a few simple bathroom checks, you can start fresh and travel worry-free.
Step 1: inspect the cassette toilet in your caravan or motorhome
Most caravans and motorhomes have a cassette toilet installed in the bathroom. Before you depart on your first trip, take a moment to review:
- Does the waste holding tank slide in and out smoothly?
- Does the blade inside the toilet bowl open and close smoothly?
- Are there no visible signs of wear and tear?
A properly working caravan toilet is the first step towards a worry-free holiday.
Step 2: inspect the flush water system of your cassette toilet
Cassette toilets have built-in flush systems for added comfort. While some cassette toilets have their own flush water tank, others are directly connected to the freshwater system of your leisure vehicle.
If the toilet flush isn’t working properly, there are a few things you can check yourself:
- Start with the fuse
Hold the fuse up to the light. If the small wire inside is broken, it needs replacing. Luckily, this is a simple fix with a readily available spare part. - Check the pump
Take a look at the pump for any signs of limescale or dirt build-up. If you notice anything, it’s best to contact your local dealer. They can clean, repair or replace the pump if needed. - Inspect the flush button
If the flush button isn’t responding, it may need replacing. This is usually an easy way to get everything working effortlessly again.
To get a smoother flush, use Thetford Aqua Rinse Concentrated in the flush-water tank, or Thetford Aqua Rinse Spray directly into the toilet bowl if your cassette toilet is connected directly to the freshwater tank.
Step 4: treat the grey water tank
When bad odours start to occur in your motorhome, it’s often not even coming from the toilet but from the grey water tank. Unlike at home, the siphon in your vehicle doesn’t always block odours completely. That will bother you, even when you’re not driving.
You can simply add a dose of Grey Water Fresh Concentrated via the sink or shower drain to travel odour-free.
Step 5: deep-clean for a fresh reset
While a second-hand caravan or motorhome usually is cleaned when you buy it, it’s always a nice idea to start fresh with a thorough clean.
- Clean the inside of the toilet bowl with Thetford Toilet Bowl Cleaner
- Clean the outside of the cassette toilet and other plastic surfaces in the bathroom with Thetford Bathroom Cleaner
- Deep-clean the waste holding tank with Thetford Duo Tank Cleaner Concentrated, which removes limescale, encrusting and grease deposits from inside the waste tank
Step 7: small upgrades that make all the difference
Not feeling comfortable using a pre-owned cassette toilet? There’s no need to replace the entire unit. Instead, some small replacements and updates can make all the difference.
Fresh-up Set
The Thetford Fresh-up Set gives you a brand-new waste holding tank, seat and cover to keep your cassette toilet fresh for years to come. This is a sustainable and cost-effective upgrade.
Frequently asked questions
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We kindly like to direct your attention to our Duo Tank Cleaner Concentrated. It is suitable for both the waste and grey water tanks.
This exceptional deep-cleaning product effectively eliminates limescale, stubborn dirt, and grease residue. Furthermore, it is able to clean the technical components within the tanks, significantly extending their lifespan. The best part? No scrubbing required! By recommending that customers use this product 2–3 times a year for maintenance, you can save a lot of time for the mechanics in your workshop.
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Twusch is a porcelain inlay designed to fit inside the bowl of a Thetford cassette toilet. It is scratch-resistant, easy to clean, and helps improve flushing performance while extending the service life of the toilet. With a maximum of 800 g, it adds minimum weight to the RV.
For a leak-free installation, use a premium sanitary silicone suitable for bathroom applications. By following the included instructions, the sealant ensures optimal fixation and sealing of the Twusch inlay within the plastic toilet bowl.
A suitable Twusch model is available for all Thetford cassette toilet series, including C2/C3/C4, C200, C220, C250, C260, C400 and C500.
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Empty the waste-holding tank (toilet waste tank) when it is full or starts to smell (4 to 5 days for Thetford Blue products, 3 to 4 days for Thetford Green products), use Thetford Aqua Soft quick dissolving toilet paper to prevent clogging. Regularly clean the outside of the toilet with Thetford Bathroom Cleaner and clean the toilet bowl with Thetford Toilet Bowl Cleaner when necessary. Finally, clean the waste-holding tank and grey water tank (tank that collects waste water from sink and shower) with Duo Tank Cleaner Concentrated 2-3 times a year to keep all moving parts inside the tank at peak operational level and to prevent odour formation during winter storage.
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Toilet additives are important for cassette and portable toilets, as they serve several purposes. They offer a practical way to temporarily store toilet waste you would flush down the sewer system at home in a safe and practical way. They also help prevent odours, gas buildup and hard to empty waste-holding tanks. Additionally, they can help to reduce the risk of blockages in the plumbing system. By using a toilet additive, you can ensure that your mobile toilet operates effectively, efficiently, and hygienically.
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Scale, encrusting and grease deposits build up over time, possibly causing nasty smells. Duo Tank Cleaner Concentrated has been especially developed to get rid of these. Once you have used Duo Tank Cleaner Concentrated, your tanks are clean again and smells will be gone. Use Duo Tank Cleaner Concentrated 1-2 times during the season and before winter storage. During normal, regular use of the waste-holding tank and grey water tank, please make sure you use an Aqua Kem® product in the waste-holding tank and Grey Water Fresh Concentrated in the grey water tank.
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To empty the waste holding tank of a cassette toilet, follow these steps:
- Locate a dedicated waste disposal facility
- Remove the waste-holding tank from the vehicle
- Keep the vent button pressed down during emptying to prevent unwanted splashing, and to allow the contents to drain into the designated waste disposal facility
- Close the valve and securely fasten the waste-holding tank back into place
- Rinse the waste-holding tank and toilet cassette with clean water until fully clean
- Watch the video below for full instructions.
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Thetford offers Blue and Green products for the waste-holding tank (your toilet tank). Aqua Kem Blue Concentrated is best for odour control and waste management in areas with access to proper waste treatment facilities. Aqua Kem Green Concentrated is good for septic tank use and is a more environmentally conscious choice. Waste-holding tank products are available in liquid, pre-dosed dry product, or liquid pod form.
Use Aqua Rinse products to keep the flush water clean and to improve flushing. Aqua Rinse Concentrated is specially designed for RV’s that have a seperate flush water tank and Aqua Rinse Spray is for cassette toilets that have a flushing system connected to a central water tank.
Your grey water tank is the one that contains the waste water coming from your sink and shower. Grey Water Fresh Concentrated is aimed at preventing nasty smells and keeping the grey water fresh and clean.
For periodical cleaning of the waste-holding (toilet) and grey water tank (all waste water except toilet waste), Duo Tank Cleaner Concentrated is your best bet.
Use Toilet Bowl Cleaner and Bathroom Cleaner for daily cleaning of the toilet and plastic surfaces in your vehicle.
