The three most common styles of RV Toilets are:

  • Portable Toilets
  • Cassette Toilets
  • Holding Tank Toilets

Portable Toilets: These are the the cheapest option and great for small campers with limited space as they can be stored away under a bed or in a cupboard when not in use. Portable toilets have two separate water tanks – one  for waste and one for flush water – and the tanks can be separated to lighten the unit when the toilet needs to be emptied.  All portable toilets have a built in pump for flushing and most have built in tank level indicators.


Thetford Porta Potti Excellence.

Thetford Porta Potti Excellence.


Prices for portable toilets can vary from $70.00 to $300.00 , the “Thetford Porta Potti Excellence” (pictured above) costs around $270.00, has an electric flush and is powered by a couple of AA batteries.  The seat on the Thetford Porta Potti Excellence is a little higher than most making it more comfortable.

Cassette Style Toilets:  These are common in larger camper vans , motorhomes and buses and need to be fixed to a wall.  Cassette toilets have a built in holding tank that fits neatly under the bowl, this tank is called the “Cassette”  and can be removed through an access door usually supplied with the toilet.  The toilet is usually mounted against an exterior wall of the RV then the access hole is cut into the wall of the RV and the cassette can be removed from the outside for emptying.

Cassette toilets come in a few different styles and options, some have a built in flush water tank which allows you to carry more water, and with the extra flush water tank you  have the option of adding deodorizing chemicals to the flush water.  Other models plumb directly to the RV water pump and use water from the main fresh water tank for flushing.


Thetford c200 Cassette toilet with swivel bowl.

The Thetford C200 Cassette Toilet with a swivel bowl has a large footprint area because the Waste Tank is built in to the base.


Some models of Cassette Toilets use a hand pump for flushing while others use a 12 volt pump wired into the RV electrics.   Some Cassette toilets have plastic bowls while others have a ceramic bowl and some have bowls that swivel 180 degrees like the one pictured above.

When I installed this Cassette Toilet in my Camper Van I didn’t want to cut two more holes in the body work, so I built a short wall at the rear of the Camper Van using plywood  and Fibreglass and then I mounted the toilet to this wall.  The exterior walls in a van are never straight but the Toilet and access doors are designed to fit against straight walls.  Because of this I decided that building a short straight wall would do a neater job.  In the photo below you can see the cassette door (with the waste cassette partially pulled out) and a small door above it – this  is the filler for the flush water tank.  This model RV toilet has it’s own 7 litre flush tank.


Thetford Cassette Toilet

Removing the Cassette from a Thetford Cassette toilet


Cassette toilets are super easy to empty and can be emptied into campground toilets or highway rest stops and there is no need to carry around the Stinky Slinky hose with Cassette toilets. Some of the larger 19 litre tanks have a slide out handle and wheels like most roller travel luggage have.  Thetford cassette toilets come with a handy set of templates to use when installing their toilets to make sure that you cut all the holes in the correct places.  When you install a Cassette toilet with its own flush water tank there is absolutely no plumbing necessary.


Holding Tank Toilets:  These are generally used in larger RV’s and are popular in North America.  The holding Tank is usually mounted under the floor of the RV and can be any size.  Most use a 3” drain outlet then 3” ABS plumbing fittings with a shutoff valve.  The inlet to the Holding tank varies in size depending on the type of toilet used.


Dometic gravity flush toilet

Dometic gravity flush toilet


  • Gravity flush- these toilets must be installed directly over the waste holding tank as the bowl empties directly into the holding tank.  This type of toilet has been around for years and is reliable and simple.  The Gravity flush toilet uses a smaller footprint in the bathroom than a Cassette toilet and you can use a larger waste holding tank, however you need room under the floor for the large waste tank.  This can be challenging with a campervan, so is best suited for larger RV’s.


  • Vacuum flush- these toilets also use a holding tank although the holding tank can be mounted away from the toilet.  Waste is pulled from the bowl through a vacuum vessel and a macerating vacuum pump, then pumped to the holding tank.  The pump on a set up like this needs to have a 12 volt power source.  After the toilet has been flushed the vacuum pump has to run for a few seconds to build up the vacuum for the next flush.


  •  Macerating flush- these toilets also use a holding tank and motorized blades to break down the waste into a semi liquid state helping it to flow better, this allows the toilet and the holding tank to be positioned apart from each other.  Draining the tank is easier because the waste can flow better.