We use the onboard Motorhome water tank for all our water for drinking and washing unless it acquires an unpleasant taste when we will fill a small container directly from a drinking water tap (eau potable) or very occasionally purchase bottled water which is a lot cheaper abroad then in the UK however when in Scotland this is niot a problem .

Motorhome Hire Scotland

Some people use a hosepipe to fill their Motorhome onboard water tanks. Scottish Tourer recommend a short 5 metre length of 13mm bore food quality plastic tubing that can be obtained from an Aquatics shop but more often than not refill the tank using two water containers a 10 litre rigid one that fits in the passenger door footwell and a collapsible 15 litre container. I usually replace this at the start of each year and use last years as a waste grey water container. It is easier to carry two smaller containers from the water tap than struggle with an unbalanced larger one!  For the two of us I usually top up our 45 litre on-board tank in the evening and just before we set off the next morning and get a bit of exercise!  (link to our water filling ) In Scotland there are many place to fill the fresh water tank of your hire / rental  Motorhome

Motorhome Hire Scotland

Obviously if you have large capacity tank it will be easier to fill it at the service point but we have sometimes queued for a very long time while other motorhomers fill their tanks and drain their grey waste.


This is the water collected in a tank from the kitchen sink, bathroom basin and shower tray. If left for a while it can become rather smelly so empty the tank frequently especially in hot weather and avoid letting food particles down the plughole when washing up. Many motorhomes don’t have a U-bend trap in the drain hoses allowing odours to get back into the van. Also due to the low level of  the shower waste points, if the underslung waste tank is nearly full the grey water can flow back into the shower tray when driving around (the plugs never seem to stay in place)!

Motorhome Hire Scotland

Sometimes there is a suitable drain or grille at the service point hopefully well designed with a long trough sunken below the ground level but often careful positioning of the Motorhome to align the drain hose is required. It would help if site owners painted a white line on the road to indicate the fore and aft position of the drain!


If moving on from day to day we generally empty the cassette and top up with fresh water whenever there is an opportunity and the service point is to an acceptable standard. From experience it can be an avoidable problem if the waste tank is full to brimming and  . . . .!)

There are various options for fluids to use in your cassette toilet.

Thetford Aqua-Kem fluids are available throughout Europe and Scotland and are fitted to most Motorhome  hire / rental companies Motorhomes. The blue fluid for the holding tank is not allowed to be disposed of at some waste points which can be a problem if you’ve been travelling and need to empty a cassette that’s been charged with blue fluid!
Motorhome Hire Scotland
Originally the normal toilet fluids contained formaldehyde which can cause damage to the processes in septic tanks and natural sewage systems. Genuine Thetford Aqua-Kem has not contained formaldehyde for several years but several other brands of blue fluids still contain this chemical. The green versions of toilet fluids are considered safe for all waste drainage systems however we have found that they are not so effective and mask the contents of the waste tank rather than break it down.

There are new fluids now available for the Motorhome hire company that use an aerobic (needing oxygen) biological reaction to break down the waste into a product that can be safely disposed into any sewage system drains. The most well known one in the UK is Biomagic which is available at motorhome shows and by mail order. A small amount of the concentrate needs to be added to the waste holding tank regularly We have tried this and found that in hotter weather it needs to be dosed each day and the cassette emptied more frequently. Also it is essential that the cassette of the motorhome  is thoroughly cleaned and any residues of blue fluid removed before changing over to this fluid otherwise the biological reaction is “killed”. Other brands of biological toilet fluids are now becoming more available. This fluid can also be used in the flush water tank (where fitted as a separate tank).

Motorhome Hire Scotland

Another alternative favoured by some users is the SOG system which does not require the addition of any fluids. The waste holding tank is modified to provide an extraction fan which draws air into the tank increasing the aerobic breakdown of the waste materials. However some users and others standing nearby! have found that emptying the untreated waste is a smelly and unpleasant experience. Also the fan is meant to have a carbon odour removal filter in its outlet which has been to be replaced (similar to cooker hood filter materials) otherwise aromas can waft to nearby motorhomes or even into your own awning if on the same side as the cassette service door!

Motorhome Hire Scotland

The flush fluid tank which is separate from the fresh water tank on most toilet installations in a motorhome can have a (usually) pink fluid added which is perfumed and contains detergents to “lubricate” the bowl surfaces when the toilet is in use.

The toilet waste disposal point on campsites is sometimes labelled with the words Chemi WC or Kemi — and may be a properly constructed drain with water tap for flushing out the cassette of the motorhome hire.

We have occasionally had to empty the cassette discretely into the toilet (WC) – Always take some paper towel and some water in a container to clean up any splashes or spillages.

NEVER GO ANYWHERE NEAR A FRESH OR DRINKING WATER TAP with any part of your cassette. Unfortunately you may see other motorcaravanners / motorhome owners not exercising the same level of hygiene standards. At some basic aires there may be only one tap. Some people use disinfectant wipes to clean the tap and handle before using it.

Once the cassette is emptied you should add a couple of litres of clean water into it with the new charge of toilet fluid before fitting back into the motorhome.

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