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Waste Water and Other Nasties

As with water supplies we give little thought at home to the stuff that goes down the drain!  In our motorcaravans things are rather different since we don't have mains drainage and therefore need to dispose of motorhome waste quite frequently.  

Waste Tanks:  Good sized grey waste outlet (40mm German)The waste tank is often very different to the fresh water tank - often situated right at the back overhanging the rear axle where the designer’s intention is that you travel with it empty.  Waste tank capacity is usually less than that of the fresh water tank since some water from the latter is consumed or even used for toilet flushing.  Surprisingly grey waste disposal is often the more difficult problem since suitable grey waste disposal points are regrettably rare!  ‘Suitable’ here means situated so that you can drive a vehicle close to them in any weather and drop your grey waste under gravity alone.  This is also when you discover that designers using crude ” plastic taps buried under the vehicle are doing you no favours at all; they may be easy enough to demonstrate in the showroom but you try using them in wind and rain on a muddy Welsh hillside!  Our latest ‘van has a large easily accessible tap opening a 40 mm waste pipe, bliss! 

Campsites may provide excellent motorhome waste disposal points where you just drive onto a concrete hard-standing with built in waste gullies or rather difficult to access raised and guarded drains designed for pedestrian access.  Informal farm sites may ask you to dump grey waste "in the hedge" - or at least as close as you can get to it without getting stuck!  European 'aires' usually have good facilities for motorhomes.  In desperation in the UK many of us resort to dumping our grey waste down town road drains but I must warn you a) that this is technically illegal even though millions do it car-washing every weekend and b) that you really must not do this in rural and roadside locations where surface water often goes into the nearest ditch - then stream & river, where our waste can cause problems and damage wildlife.

Some motorcaravanners like to carry a small waste container to draw off some water occasionally because they feel it's not always convenient to move the 'van to a drain.  Deciding on things like this has more to do with available storage space and with individual perceptions of convenience rather than any real necessity!  Of course, if your outfit has no waste tank you'll need some kind of catch-it container anyway.  There are rigid portable waste containers but they take up space - if that is at a premium then the bag-like, roll-it-up-for-stowage kind is a better bet.  And there is always the humble bucket, it has its place even when you have a waste tank - for vehicle washing or perhaps for waste in freezing conditions.  Although a little awkward to store, do remember it is a storage container in itself; it's especially useful for storing hook-up cables that can be wound into place inside the bucket.

It would be nice, of course, if one could just plug in to main drains water as at home.  That has long been possible on many sites in North America and such facilities are now starting to appear on some of the more developed sites in Britain. Best known is the so-called 'Superpitch' system that can include fresh water, drains, electricity, telephone, tv and even sewers. 

Winter:  As with the fresh water issue, ask yourself 'do I want to use the motorcaravan in winter?'.  If so, then ideally you should buy a ‘van that has its tanks and plumbing contained within the heated interior.  External tanks and pipe-work runs can be protected against freezing by insulation, although that alone only delays the onset of ice formation.  Again individual life style comes into play - if you intend to camp in seriously sub-zero temperatures and will be out on the piste for hours then you need to fit a thermostatically controlled immersion heater in the tank(s).  There are units which operate on both 12 volts and mains power.  If on the other hand you mostly stay in the warm and admire the view through your double glazed windows then the heat that keeps you warm will often keep the water from freezing too.

When the waste tank might freeze you could leave its drain cock open and let water run straight through into a bucket and still be able to empty that when the purpose-made waste receivers would just imprison their frozen contents!  We sometimes experience problems with the exposed waste gate & tap freezing even when the rest of the motorhome is fairly warm so we're looking at improving insulation in that area.  If you don’t want to use your motorhome at all in Winter then you must drain down all water at the end of the season according to the makers instructions, remembering to include the waste tank.  Leaving drains open helps to keep the tanks fresh but do remember to use some gauze or mesh to keep out unwanted wildlife; the odd drain smell is nothing compared to dead rodents!!

Maintenance A generous waste tapMotor caravan waste water systems seldom benefit from the deep water-seal trap which features in domestic installations so unpleasant odours can sometimes drift up from the tank. The first defence is to leave the plugs in all drain fittings.  The second safeguard is to try to prevent the tank contents becoming malodorous.  You may find it helpful sometimes to add some cleaning agent like the new ‘Thetford Tank Freshener’ to the waste tank while out and about.  Just pour some down the various sinks and drains along with just a little fresh water.  On the road it will mix with your washing-up water and slosh around nicely doing its thing.  When you reach your destination drain the tank immediately before any sediment can settle out and flush with some clean water from your taps.  This process is particularly useful on the final run home after a trip to make sure the tank stays in good order.  You can of course add a little extra freshener to stand in the tank until your next trip too.  Strong household chemicals are not recommended since you may have to dispose of the tank contents somewhere where main drainage is not available - on a rural site for example. 

Rubbish:  No great problems here, just bundle it up into small plastic bags as often as you can and dispose of in rubbish bins.  Every site will have some, even small informal farm sites - though we were once asked to "take our rubbish home with us" by a very eccentric and very remote farmer who was in dispute with his council over collection!

Toilets:  A subject that often seems to be ignored despite its importance!  This section is written in a way that we hope is both frank and informative but polite.  We hope you find it useful even if you are of a delicate disposition!

Motorhome toilets fall into two categories, chemical toilets and holding tanks.  Chemical toilets are the most common nowadays and in 'cassette' form looking just like an ordinary toilet often complete with electric flush too.  The cassette is the waste holding portion usually accessed through an outside door.  The main manufacturer is Thetford and these units are sometimes known as "Thetfords" or "Cassette Toilets". The term "Porta-potti" is a trade name of Thetford and may be applied to any of their products but is usually used to refer to the completely portable toilets used in older and in more compact modern campervans, a trio are illustrated left. They work on exactly the same principle as the cassette but the toilet, waste tank and flush water tank are all integrated into a single portable unit.  Somewhat confusingly the removable cassette is often called a holding tank by the makers. These are replaceable when they get too mucky to continue with - we regularly sell them from our on-line shop.

Cassette toilets and porta-pottis are made of quality plastic to save weight.  The human interface is made to look much like a conventional domestic toilet except that there is a shutter in place of a water trap.  For use the lower section is charged with a small amount of a toilet chemical, typically Aqua-Chem Green, plus about a litre of water, this may last up to four days but many of us prefer to empty more frequently.  Total capacity is typically 15-20 litres.  For emptying the bottom section is detachable / removable and can be carried sealed to a chemical disposal point or 'CDP' or toilet for emptying.  This waste is sometimes known as 'black waste'.  The modern 'green' chemicals are bio-degradable so they break down in the environment rather than polluting it. Note that they simply work as 'pong arresters' so beware of exceeding the four day limit especially in warm weather!  The raw chemical has a strong citrus type scent that some find pleasant and others dislike.  The older non-bio chemicals are now banned in many countries and on farm sites, they shouldn't be deposited in public toilets either.  Most were/are formaldehyde based and there is now evidence that this can be harmful to humans especially when the fumes are in a confined space.  I predict they will be banned throughout the EU eventually.  Flushing is by electric push-button or hand pump and the flush water may come from a separate tank or from the main water supply.  The latter is more convenient but the former offers an opportunity to put sweet smelling stuff in the flush water.

Holding tank toilettes may have a similar initial appearance but the waste products are stored in a larger semi-sealed tank of substantial capacity.  This is similar to those used on boats and they are sometimes actually marine toilets.  A few have removable tanks but most are fixed and the waste is disposed of by pumping out.  The up side is the relatively infrequent emptying and the absence of chemicals, while the down side is the need to handle sewer pipes dispensing raw sewage. 

There is a variant of the cassette that mimics this on a small scale.  The product is branded SOG and seals the cassette itself via a valve containing activated carbon to absorb smells.  A fan pulls air through this when the toilet is in use to prevent odours entering the motorhome.  All very green but emptying is not always very pleasant!  The new vacuum toilets from Thetford can have a removable holding tank which bigger than a standard cassette but small enough to lug about - just - if pump-out facilities aren't available.

In use there are some differences to home toilets.  First there is a debate about whether to open the flap before or after making a deposit and then there is the inherently less slippery surface of the plastic compared with porcelain.  The flap debate will continue but a number of solutions to the slip/stick issue have been found.  Some line the bowl with toilet paper, some say a wet bowl works better so do a pre-flush, while others spray on a quick application of a silicone based product like WD40 or silicone furniture polish!  Some concerns have been expressed over bunging up the toilet with too much paper and also about the long term effect of things like WD40; in the end you'll have to make up your own mind.  My favourite tip is the one that advises keeping a made-up solution of something like Fenwicks Top & Tail in a squirt bottle (like the ones used to mist house plants e.g.); after using the toilet simply set the bottle on squirt rather than spray and use to dislodge 'klingons' as required!

Cassette emptying is fairly straightforward if a bit heavy at times. Most campsites, and even farm fields have 'CDP's - Chemical-toilet Disposal Points. These can be anything from a hole in the ground to a sophisticated purpose built unit. The best allow you to stand upright while emptying and provide safe resting places for the tank and for the cap along with splash guarding and easy water rinsing. Regular sales of 'spare' caps are made to those who've lost one down a CDP!  Wild campers make extensive use of public toilets and may carry multiple cassettes, we carry a spare ourselves in an outside-only locker.  To empty most cassettes you remove the cap, swing out the spout, lift with the tank still level, then swiftly and deftly rotate and invert the tank while simultaneously poking the spout well down into any splash guarding - and at the same time pressing the vacuum release button on the tank!  It is actually not that difficult but beginners would be well advised to practice at home with a tank of clean water first!!

Two important tips for you: Get into the habit of closing the flap when your 'toilet' is done otherwise you'll finish up with a very smelly motorhome.  Get into the habit of opening the flap with the toilet lid down, this will avoid 'spitting'.  Spitting occurs when there are pressure changes, due perhaps to change in altitude or temperature and usually when a little water has collected on the flap; in these circumstances sudden release of the pressure when the flap is opened can cause spitting.  Chances are you'll only get hit by clean water but it really isn't the sort of experience you want - you'll only do it once!

Finally, water points are provided on site for cassette rinsing - and I shouldn't need to point it out but - never use these for water tank filling nor ever use the drinking water taps for toilet rinsing!!

See also our Aires page for foreign waste disposal info and also some appropriate foreign words.

With thanks to Motorhome Monthly for permission to use one of their articles as inspiration for this one (www.stoneleisure.com).


All material copyright Motorcaravanning.com and/or Neill & Dilys King 1999 - 2013 unless otherwise stated.