The great taboo – using your motorhome or caravan toilet

Published in Caravan Guard News, Caravanning Top Tips, Motorhoming Top Tips, Videos on   - 71 Comments

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  1. Barry Carter says:

    How ironical this article is: I’ve always been careful with the emptying and flushing of our Thetford C260 cassette toilet now in its 10th year. But last Sunday 16/07/2023 just before emptying, flushing and recharging, in preparation of leaving motorhome site I noticed toilet’s slider valve wasn’t operating correctly. Managed to remove toilet cassette and found on examination the slider valve wasn’t closing fully, after emptying and flushing it there was the sound of something large and plasticky rattling about inside. On returning home and realising something was wasn’t right with the cassette, I needed to know what was inside and found a great video on YouTube, titled: Practical Caravan – how to replace a “Thetford toilet cassette seal” –, It shows how to get into cassette and what’s inside and around slider mechanism. On inspection found a crescent shaped slider guide/limiter had sheared away from the mechanism’s body. Googled a search and found mechanism replacement cost was £30 – £45. But have fixed it for under £7 by drilling out locating pillars and their position on slider mechanism’s body, fitting and clamping it in place with 3 x M3 x 50mm SS machine screws with nylon sealing washers and SS nylon lock nuts, the locknuts being located on inside of cassette mechanism, sprayed all the rubber seals with silicone grease. On reassembly it now operates like new but a lot stronger for it. HSE wise: made sure the toilet cassette was well cleaned and disinfected and wore protective gloves.

  2. Michael white says:

    We also value our privacy and comfort, using our ‘van toilet as required so needing to frequently empty and recharge it. When swilling out the cassette it is VERY important not to do so so vigorously that the level float is dislodged or broken. They are expensive to buy, IF one can be found, and tortuously difficult to replace.

  3. Trevor Smith says:

    Don’t forget to leave a gap in the toilet flap when travelling. If not pressure builds up in the cassette and you might have any liquids left in the cassette blown out of the toilet when you next use it.

  4. Robert Barton says:

    Many years ago I was an apprentice paper-marker and in fact I have run numerous tests on toilet tissue for my on board toilet. Final result :- there is no difference between normal household toilet tissue and the so called very expensive caravan tissue. In fact there are more sheets per roll on household toilet tissue.

  5. Jon says:

    For cleaning the bowl I used a foam cleaner and a thick kitchen towel – no contact with me and great fragrance. Foam cleaner generally around the motorhome is better than liquid everywhere as we know.

    Also the Jeyes Blu blocks when used in domestic cisterns will eventually foul the mechanism and I’ve seen it happen. The thick blue stuff layers onto the valve etc. So I wouldn’t trust blu blocs or I suspect some own brand toilet fluid which appears to be jeyes blu in water.

    Best toilet fluid I found was actually in Aldi. Best fragrance.

    Also try some of the waste pipe cleaner (not bleach / gentle) and leave it to sit on the blade for a while to clean it and more great fragrance.


    This is a useful article on a topic which the main caravan camping clubs seem to avoid. A few q’s.
    1. How long does it take the blue fluid to break down a poo job?
    2. At a recent stay on a CL site the grey water and loo disposal were at the same point ….. should they be separate or not?
    3. Is the blue liquid harmful to the aquatic environment when it eventually reaches there?
    4. Do the green liquids work effectively on poo jobs?

  7. MR IAIN S MUNRO says:

    Good article.
    To save lugging large heavy loo blu bottles
    we transfer some to the Kids old Drop Shot
    drink bottles with squirt tops.
    A pair of these fit neatly next to our cassette housing, ready to shot from the hip the required no.shots.
    These last approx 10 days, so easy and no mess etc!!

  8. ray abbott says:

    if your flush button stops working is there an easy fix

  9. John Pepper says:

    Last year, on advice from a friend, we started using bio washing liquid in our holding tank instead of the Blue.. As it was a very short season it wasn’t possible to test it fully but I found it worked fine and smelt better too.

  10. Kat says:

    Please help clarify for me… When you use the toilet do you open the flap before hand so the urine/ no. 2 drops straight into the cassette, or do you wee onto the flap then flush some water, then open the flap so the wee and water drops into the cassette at the end?

    • Hi Kat, it’s down to personal preference really. Some people open the flap, wee, then flush and close, and some leave the blade closed, wee, then flush, and open the flap up to empty contents into the cassette. The main thing is to always close the flap /blade after you’ve done your business to keep smells from the cassette to a minimum.

  11. Chris says:

    Seriously there is nothing to worry about using your loo for a number 2. I’d rather take a dump on my own caravan toilet knowing when it was last cleaned and who else had used it and being familiar with and able to monitor their hygiene standards than some random cubicle which has been battered 24/7. As long as you use the right products the chemical disposal is not that bad at all… I am a new caravanner, since August last year and until I’d used the toilet and disposal point for the first time I had been dreading it up until then. I was relieved, quite literally when I discovered it’s easy as pie and the cassette always seems to keep really clean with the chemicals

  12. Chris says:

    Tip, don’t press the air release button unless holding the casette horizontally. Otherwise you will end up with a load of blue coloured waste pouring over your feet….

  13. George says:

    The flush pump some times doesn’t work and it looks like an expensive job
    to get it fixed not a bit just go to how to fix a pump on your iPad and follow the
    Instructions,clean out the pump test and replace ,simple no cost solution
    Toilet back working in half an hour .

  14. We have never used our on board toilet for no.2s, but if needs must … we have decided to give the compostable anglers’ toilet liners a try. They are single use only, but prevent solid waste going into the cassette and swilling around there until emptied.

  15. Andy Finnegan says:

    Very helpful, better to see how it should be done rather than reading in a book. Just be careful with decanting fluid / chemicals in to a bottle that is a drinks bottle.Using a bottle with a safety cap.

  16. DOREEN MARSDEN says:

    to prevent condensation over winter months I put saucers filled with salt around the van and it absorbs all moisture. You can dry out the salt and use again next winter

  17. Kevin Draper says:

    Hi great article thanks. Our booking for July has said their shower block will be closed so it’s now important to get this stuff right. One tip I would add is before emptying, open the blade for ten seconds which lets any flush fluid left in the bowl drain into the cassette. Then close it again. I sometimes forget and end up with pink fluid in the cassette housing which has to be mopped up.

  18. Barry Carter says:

    Whilst a seasoned camper and having been Motorhoming for 15 yrs I found the article very interesting especially reading the comments which I’ve never seen so many replies to. We mainly tour using the CMC and CCC club sites and so have used their toilet facilities the only times the washroom and toilet have been fully used for No.2’s is when the grandchildren have been holidaying with us. One thing I’m not quite clear on though is the SOG system, I under that it is chemical free but it only seems to be a negative pressure ventilated system my toilet is a Thetford C260 and it has a ventilation fan and filter. The filter unit connects to the base of the toilet cassette when in position, the fan can be operated prior to use or when the toilet flush is used and is timed to run for around 10 mins, I’ve changed the filter on a yearly basis and it also looks to be a carbon filter but Thetford don’t say this is a chemical free system so what’s the difference?

  19. Alan says:

    Very good article and video. Only fault let down a bit by the video showing the filler cap on the shelf which could easily be knocked into the drain. I always put mine on the floor well clear of the drain.

  20. Martin says:

    The loo should not be flushed until the loo cover has been shut. Stops germs being driven around the space.

  21. Tim Boarer says:

    Good article for those that are new to using their mh or caravan. I know you may think it’s advertising but as already mentioned by some other people. A SOG kit is by far the best way to go and totally environmentally friendly. Keep up the good work.

  22. Martin Woodhead says:

    That was a good article and very informative, we used ours fully for the first time at the national a few years ago and then wondered what all the fuss was about. I particularly thought item 5 on emptying was important as I nearly lost a cap and now it’s put way out of the way lol.

  23. Christopher Cliff says:

    Don’t forget if you have a wastmaster your toilet cassette will fit on top under your two flexy straps as this may be more stable for you to wheel to disposal area and two jobs done in one trip

  24. Steve Botham says:

    A very good article but no mention of the sog system.Would be appreciated

  25. Jason Williams says:

    Newbies beware. Raised, broad or shallow drains at the disposal point and strong winds are not a good combination, so make sure you keep your mouth closed when emptying the cassette. LOL

  26. Tony Wetjen says:

    A useful article although I have long been conversant with onboard facilities. It was interesting to learn that the cheaper
    supermarket toilet paper breaks down in an onboard facility just as well as the designated product. Thetford toilet roll
    is a good deal more expensive than the domestic variety!

    Many thanks,


  27. GRAHAM JAMES says:

    Crikey, I never thought I needed instructions as to how to empty my cassette toilet. But having said that, I didn’t know about those bowl liners; never heard of them before. I might try those. I use my toilet for both, never concerned me. One thing, I have never bothered with dedicated loo roll and I buy the same market leading classic brand I use at home (not a cheap one, but not highly luxurious) and never had an issue with it not breaking down.

  28. John Stephenson says:

    You haven’t mentioned the use of the “SOG” system of cheimical free toilet. It uses a small fan that draws fresh air though the cassette when the flap is open. The extra oxygen aids decomposition and saves the cost of expensive chemicals. It can pay for itself over a couple of seasons. The only maintenance is to replace a carbon impregnated filter perhaps once a year.

  29. Jac says:

    Nope, not in my van. Liquids only.

  30. Carl Battersby says:

    Excellent information especially for new caravanners as I remember things like this being a little daunting when you first start out, Its difficult to remember everything or expect to get things right first time. I used to put a few post-its around to help when I first started just to refresh my memory and help me get things right.

  31. Robert Hayes says:

    Why do people have a toilet an don’t use it ?, I put a cap of Zolflora into the number two catcher excludes the smells a treat an makes it sweet.

  32. Andrew says:

    Excellent article, very informative for people who will be using their onboard toilets for the first time and people like us who have been using them for years as we only really go to field type sites with just a tap and somewhere to empty the effluent. Have to admit that the cassettes are a lot smaller now than the full width old style onboard Thetford cassettes that when full you had to have the strength of Geoff Capes to manhandle.. Well done, enjoyed this video.

  33. Alan Mason says:

    With regard to adding toilet fluid, not all makes have a measurement wthin the toilet cap, such as on the Dometic Toilet. So use the guide on the additive bottle if available.
    I find it hard to understand the taboo about toilets, they are quite sanitary to use these days, not like the early ‘Bucket & Chuck it’ type introduced by Elsan some years ago!

  34. David Jones says:

    I have one of the older, larger Toilet cassette’s and because the wheels on the cassette are not designed for use on rough ground I use a folding sack trolley. I bought it in one supermarkets. I use a bungee hold the cassette and tank liquid, spare gloves onto the trolley.

  35. Paul Clarke says:

    An informative article / video for newbies and the slightly squeamish alike. The only warning I have is that before emptying the cassette remove the slider from over the entry aperture (cassette seal) because if like mine it is a little bit loose, guess where it’s going to end up as you gently shake out the contents into the disposal point.

  36. Richard Miles says:

    Good article. I wondered what that orange button was for! Thanks.

  37. Paul C. Rawbone says:

    Very informative

  38. DIANE LEADER says:

    Once cassette empty when you are leaving site put a tiny squirt of washing up liquid in the cassette and about 50ml of water and leave to agitate on the way home, empty out in the sewer or loo at home and bingo you have a nice clean cassette for next time.

  39. Stephen Lansley says:

    Thank you so much!
    We’ve just bought our first motorhome and your toilet cassette video is absolutely brilliant and clarified so many things.

  40. Christopher Cliff says:

    If you shake to hard this can dis connect the float linkage but is can be re fitted inside the tank

  41. Bob Cairncross says:

    You haven’t mentioned cleaning the pump for over wintering. If the pump is not sterilised black lumps of sludge can block the pump. Rinse through with Milton is suggested

  42. Graham Uffton says:

    How long does it normally take the blue to dissolve the solid stuff. My one experience was not at all after 12 hours in the tank and found it hard to shake out – it wasnt the best experience. Is the idea if stuff doesnt come out first time, just leave it in there and let it continue to break down?

  43. Sheila Rae says:

    Common sense and as we often stay on a French Aire’s, this is what we do regularly. It is after all, why Motorhome are so convenient.
    We would rather use our own facilities than those on some campsites – particularly in France on many occasions! We know how clean ours are but unfortunately, not all campers are as particular – even without Covid 19

  44. Mrs Susan Hulme says:

    It would be good if you had been a bit more specific about what to use to clean the bowl..but a good article. Ty.

  45. Anne Harris says:

    When using a drinks bottle for chemicals always label. Either what it is or ‘do not drink’ sorry to be pedantic but it’s best to be safe. Best wishes Anne Miller

  46. Wendy Wake says:

    This very true bout cleaning nd maintaining the toilet after we’ve used the toilet in winter we out a small amount of diluted ZOFLORA into the cassette leave hatch open it keeps ur toilet smelling nice always check ur caravan before during the winter if it possible to do so put condensation bags in bathroom toilet kitchen living room u may need bowls or bucket to catch to drops for condensation bag help keep damp nd mould away we use the yellow bags as u can dry them out in ovens or radiatas reuse them there a great produce to buy we out bout 6/8in sliver the caravan

  47. John says:

    Very helpful

  48. Susan Fox says:

    I never use on site facilities i always use our on board toilet and shower, I like my personal privacy and its no problem at all , clean and no smells.

  49. David Vernals says:

    I found this video very helpful and will use the information presented in it on our next trip thank you. I rate this at 4.6.

  50. M McNulty says:

    We used to buy the blue sanitary liquid but it is not cheap. If like us and you empty the cassette between 1-2 days (No:1s only) or immediately after an emergency No:2, this can be expensive, refilling with the required blue. We now use Jangro lemon gel floor cleaner (available in 5 litre bottles) or a very cheap brand of fabric conditioner instead, saving a large amount when touring for over 4 months each year and unlike the blue liquid, they do not contain formaldehyde, and they have never let us down. Also over time, the blue deteriorates the polystyrene float inside the cassette thus disabling the FULL warning light on the toilet.

  51. Steve johnston says:

    Very good. I now no how they work

  52. Janey says:

    I have a campervan & use a porta potty for pee only. How about this for No., 2?
    We use the blue chemical block in it rather than the liquid equivalent as if need to empty & replace it saves us our limited room & weight.

  53. Tribute8515 says:

    really good article, following advice from the well known Diamond Dave ( Dave Newbald ) we now use a Biological cleaning tablet the same as you would use in you washing machine in the cassette as it is biological it aids breakdown of the contents, it’s certainly worth watching Dave’s videos on servicing a toilet cassette in fact he has a few videos on YouTube.

  54. Ken Platt says:

    We have never fully utilised our onboard toilet, but if we must we will. We will be happy just being out in our caravan.

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