Built-In Toilet and Porta Potti
Discussing portable toilet
systems for caravans and RV's including the best chemicals to use.
What are the different
types of toilet systems for a caravan / motorhome?
The Internal Cassette Type Toilet
consists of two parts: a permanently installed toilet
seat and a waste cassette tank that you can access and
from the outside hatch. To prepare the toilet for use, you simply
add the toilet fluid and water mix to the cassette waste tank.
The flush water tank also requires filling although
there are models that draw the flush water from the RV's
main water tank supply.
timing of emptying the toilet cassette varies due to the
capacity/size of the cassette and the amount of usage.
Toilet cassette sizes range from 17 litres to around 20
litres and can be quite heavy to lift when full of waste
so we recommend obtaining a toilet cassette with wheels
for easy transportation from your RV to the Dump-Ezy
black water waste dump.
various models, with either rotating or fixed toilet
bowls, blend in seamlessly with your bathroom, making
the best use of the limited space.
The Porta Potti
Want to take a porta
potti camping? Because these toilets
are compact, lightweight and easy to use, the porta
potti is often used to take camping, in caravans, motorhomes, boats and
camper trailers. The porta potti is simple to transport
and really can be placed anywhere. It is small
enough to pull out from under your caravan bed and
slides neatly away again when not in use.
potti consists of two sections. The upper section is a
combined flush water tank and toilet bowl with
detachable seat and cover. The lower section is the
waste holding tank. These two parts are easy to attach
and detach using a lever at the rear of the toilet. In
this way, the waste holding tank can be simply and
hygienically emptied and cleaned. Most porta
pottis are equipped with a level indicator. In this way
you are warned in good time that the waste holding tank
must be emptied.
empty my porta potti / toilet cassette in septic toilets
Australia advises "Both Aqua Kem Green and Premium Aqua
Kem Green can be disposed of into a septic system"
chemicals should I use for my porta potti / toilet ?
to consider when assessing many of the different
chemicals available for your caravan's toilet / porta
potti are -
the chemical chosen
suppress unpleasant smells;
promote the breakdown of solids and toilet paper;
protect moving parts and extend the life span of
your toilet / porta potti;
reduce formation of gas;
keep your waste tank hygienic and clean;
environmentally free standards ie: is it
Why should I choose formaldehyde free
toilet chemicals ?
What is formaldehyde ?
It is defined as ‘a chemical used in manufacturing
and chemical industries, and as a preservative by
anatomists, embalmers, and pathologists. Being exposed
to formaldehyde may increase the risk of developing
leukaemia and brain cancer.’
Formaldehyde is toxic to animals, plants and humans and
exposure may cause irritation to the eyes, throat and
nose and can cause lung and skin allergies. It is often
used as an active ingredient in toilet chemicals to
break down and sterilize the ‘black water’ or toilet
Toilet waste containing the formaldehyde chemical is
really only suitable for disposing of in sewerage
in the city where there is sufficient water and other
wastes to break down or dilute the formaldehyde. When
travelling in regional or remote areas it is not
suitable to dispose of in drop toilets, country town
septic toilets or even buried in the bush.
Some regional towns have CMCA/ KEA sponsored ‘dump’
points however if your toilet cassette or ‘black water’
waste contains formaldehyde it should not be disposed of
in those facilities as it can de-nature the waste
breakdown. There is also considerable cost for local
shire councils to remedy the problem as they often lack
the availability of sufficient water to dilute the waste
Some toilet products may also be formaldehyde free but
unsuitable for recirculating toilets and holding tank
What is a vacuum toilet ?
A vacuum toilet is a toilet system developed for
caravans and motor homes. It comprises a toilet
bowl from which extends a pipe to the cassette.
It operates similar to a toilet on an aircraft
so when you flush, the vacuum in the line sucks
the contents in the toilet bowl, using very
little water, to the tank.
One manufacturer, Dometic, supplies ceramic
toilet bowls with a vacuum toilet for caravan,
motorhomes and marine sailing and power craft.
The manufacturer claims the action of the vacuum
breaks the waste down so no chemicals are
required. They promote the benefits as odour
free, extremely low energy and water
consumption, as well as allowing greater design
flexibility due to the remote cassette
The vacuum pump requires power to operate and if
by chance your battery is flat it will not
One point to consider though would be not to
locate the remote cassette under your bed as the
pump runs for about 60 seconds to reset the
vacuum and this may be inconvenient, for the
sleeping partner, if it is used during the
Another of the Dometic models has a holding tank
system suitable for coaches and motorhomes.
These holding tanks are available, depending on
the manufacture of your vehicle, in 35, 60 and
90 litre capacity. Dumping is at the push of a
button with a small bore hose to a nearby
toilet is vented to the outside of the RV, has
no holding tank and does not use water in it's
operation. A 12V fan is the only power to the
unit and an agitator hand is attached for manual
use. The liquid waste (urine) and solid waste
('poo') are kept separated and it is necessary
to add compost material (such as pre-moistened
peat moss or coconut fibre) to the base of the
unit. After each solid waste addition the
compost material must be agitated 2-3
revolutions with the handle to mix the waste
into the compost. Published material indicates
about 80 uses for solids before emptying.
An 8 litre
sterile liquid (urine) waste canister can be
emptied every few days into any public toilet
names are 'Natures Head' and 'Air Head' and
Natures Head comes with a five year warranty.
Google their websites for full details on the
operation and installation of these composting
SOG Toilet Ventilator
The SOG toilet ventilation system is a 12V
fan kit system that can be connected to
toilet cassette holding tanks. There are 4 kit types - Type
A kit system is for the C2, C3 and C4 models. Type B for
C200, Type D for C400 and Type F for C250/C620
Installation instructions are included with the SOG kit and
it comes with a 2 year warranty.
The SOG toilet ventilation system comprises a
90 degree connecting elbow which is inserted into a 35mm
hole drilled into the elbow of the pour out spout of the
an exhaust hose that connects from the elbow of the pour out
spout to a 36mm hole in the cassette door where an air exit
hole is covered by a filter housing containing a carbon
filter. Replacement carbon filters are available and it is
recommended the carbon filter be changed once
are connected to the 12V caravan supply and once the blade
valve is opened the ventilator
The unit will stop
as soon as you close the blade valve. The power current
consumption is stated at 0.43 Watts and only uses this while
the toilet is in use.
Information available with the SOG toilet
ventilation system states no toilet chemicals are needed as
decomposition is optimum due to the increased oxygen flow.
There are no smells as the fresh air acts as a seal and
prevents smells from rising with the smell ventilated
outside the RV through the carbon filter. It states that you
can use normal commercial toilet paper and this is fully
decomposed and the toilet cassette can be emptied every 5
days (or when full).
To empty the toilet cassette the hose from
the connecting elbow
be removed and a stopper is provided to plug the elbow. If
removing the hose is difficult spray the stopper and plastic
parts with silicone spray.
SOG Toilet Ventilators are available from
Aussie Traveller, caravan accessory stores and online
caravan, motorhome & RV accessory stores.
See also our pages on
Sanitation Products/Toilet Chemicals and Home Made Portable