Motorhome toilets: all you need to know

Only empty your motorhome toilet cassette at a designated disposal point, which will be labelled as chemical disposal point (CDP), Elsan disposal point or even sluice room.

Three essential pieces of advice at the disposal point are:

• Always put the cassette cap on the floor. If it is on an adjacent wall or shelf, sooner or later it will get knocked into the disposal bowl
• Always press the vent button when emptying to avoid unpleasant discharge splutter and splashes
• Always keep upwind of your cassette at an outside disposal point.

Thetford recommends emptying the waste tank before travelling if the tank is over three-quarters full. Most cassettes have a pressure-relief valve, which can also allow liquid waste to escape during vigorous motion unless the waste level is low. Similarly, if you have a separate flushing tank, then keep the level low when travelling.

Emptying the cassette is simply a task requiring strict observance of hygiene procedures. Never smoke or eat or touch your face during proceedings and thoroughly wash your hands after. It’s better to wear gloves, preferably disposable gloves.

Cleaning a cassette toilet

Regular cleaning of the toilet bowl and cassette is essential to maintain the system. The big mistake newcomers often make is using domestic cleaning products, which can damage the plastic mouldings and rubber seals that keep the waste and smells within the holding tank.

Use only products made by the cassette manufacturer – such as Thetford’s Bathroom Cleaner – or specific motorhome toilet cleaners made by reputable companies.

The waste holding tank will tend to scale and slime up over time, hence a good soak overnight with a proprietary waste tank cleaner solution, like Thetford Duo Tank Cleaner Concentrated, will keep it clean and odour free. Spray Thetford’s silicone lubricant onto the rubber lip, vent and pressure relief seals plus the slider cover after cleaning the tank, but never use Vaseline or vegetable oils. Do this two to three times a year.

Cassette toilet winter maintenance

As soon as frosty weather approaches, ensure your toilet flush and waste tanks are emptied. After draining, always press the flush button a few times to clear the pump of residual water to avoid frost damage. Leave the valve blade open to ventilate the tank and prevent the blade sticking. If you camp in winter, ensure there is heating in and around the toilet location when icy conditions are anticipated.

It’s worth using an additive like Thetford’s Aqua Rinse in your flushing tank or Aqua Rinse Spray direct to the bowl to keep the bowl clean and smelling fresh. Both products tend to permit greater slippage on the bowl surface, thus reducing smears.

If you’re considering a used motorhome, but shudder at the idea of using someone else’s throne, or maybe you feel your toilet needs a makeover, then you can replace certain components without needs to swap out the whole toilet. Thetford’s Fresh Up Kits include a new waste tank, seat and lid. It’s like getting a whole new toilet fitted in two easy steps. These are available for the C2/3/4, the C200, C250/260, C400, C500 and C220 models.

And for an easier-to-clean Thetford toilet bowl, you can fit the Twusch, a porcelain inlay that is scratch resistant. It will only use up 800g of payload, too.

You can get special toilet paper that dissolves more readily than domestic toilet paper for use in the motorhome. This makes for easier emptying and helps prevent clogging. While budget toilet paper also has these properties, Thetford’s Aqua Soft is more gentle on the skin and feels like a more premium domestic product…

And, although obvious, things like cotton buds and wet wipes may clog your cassette and certainly disrupt, if not damage, sewage disposal systems.

Spares are readily available, particularly for Thetford products. Cassettes since the C2, C3 and C4 models have incorporated a large bayonet-style opening aperture into the tank interior. This gives access to the lip seal, float arm and blade mechanism and eases the replacement of other components.

The removal of the access cover is achievable by using the slide cover to turn it around. If it’s particularly hard to move, try a piece of timber cut to form a snug fit to get better leverage but take care not to stress one corner of the slider cover runner.

When replacing seals, a lip seal costs around £12. Alternatively, you can replace the aperture cover, complete with blade mechanism, lip seal and, in some cases, the level indicator arm for around £40.

If other seals on the vent button and pressure-relief valve need replacing, consider Thetford’s Fresh Up sets for around £100. These contain a cassette tank, plus new seat and cover at less than the cost of a new cassette. 

When cleaning and rinsing out the waste tank, only shake gently or you may dislodge essential parts.

Level indication failures can sometimes be due to a build-up of toilet paper on the float arm.

Electrically operated controls can be vulnerable to moisture damage, such as phantom operation of the flush pump, so it’s worth switching off the appropriate electrical circuit before leaving your motorhome.

Flushing tanks sometimes suffer from the presence of black bits caused by not completely draining down the tank prior to a long lay-up. Thetford recommends using a weak solution (100ml to 10 litres of water) of household bleach.

Fill the flushing tank with the bleach solution and, after 24 hours, drain the tank and refill with clean water and drain. Then repeat the clean water fill and drain to ensure no trace of bleach is left.

• For a thorough clean, most toilet lids and seats are easily removed
• Intermittently press the flush button to create the most efficient flushing effect. A few of Thetford’s latest cassette toilets have an automatic pulse flushing action
• After emptying a cassette, add around three litres of water and this will enable the toilet fluid to do its job better and help prevent 'pyramiding' where the waste drops into your tank
• Can you poop in a motorhome toilet? Yes, but practise the paper lotus technique for keeping the bowl clean with a cross of toilet paper over the blade opening before performing. This should see your number two automatically packaged up before dropping into the waste tank