Our Guide To Caravan SOG Toilet Systems

Our Guide To Caravan SOG Toilet Systems

Is there anything more convenient than having a toilet onboard your caravan? You can enjoy the privacy of your own toilet without worrying about public toilets or portable set-ups. There’s just one downside: the smell.

That’s where a SOG toilet system comes in.

The SOG Toilet Ventilation System makes life on the road easier by promoting the natural breakdown of waste through ventilation and stopping smells from escaping from the toilet waste tank. So there’s no need to worry about carrying nasty chemical additives on your travels.

Let’s take a look at how a SOG toilet system works, the pros and cons, and essential things you need to know.


What Is A SOG Toilet System?

The SOG Toilet Ventilation System is designed to reduce odours coming from the holding tank by ventilating air outside with a fast and powerful ventilator. This means you don’t have to worry about smells escaping from your caravan bathroom.

Most ventilation systems offered by toilet manufacturers as an optional extra only provide ventilation of the waste holding tank. But a SOG system removes odours by suction directly where they first occur – in the toilet bowl.

When you open the lid to use the toilet, this activates the SOG fan. The fan draws clean air into the toilet pan, through the cassette and out to the SOG filter.

Air going into the cassette produces negative pressure and acts as a seal, preventing the gases and smells from rising out of the tank and into your caravan, meaning smells cannot escape. Also, because there is more oxygen in the waste tank, it is easier for waste to break down without the need for chemicals.

The SOG toilet system has a low 12v draw – just 0.43 watts and only consumes power when in use. The fan is powered by the same power source as the flush pump and is activated when you open the flap in the toilet bowl. Then, when you close the flap, the fan turns off, so no unnecessary power is used.


What Are The Pros And Cons?

The biggest benefit of the SOG toilet system is that it stops smells escaping from your waste tank and toilet. With toilets in caravans, instead of the waste being flushed away and replaced by clean fresh water, like at home, the waste sits festering under the seat in the sealed container. As the contents of the toilet decompose and give off gas, your toilet becomes a hotbed of foul smells every time you open the toilet lid.

Of course, you can use chemicals to hide the odour but even the toilet chemicals have a smell that can infiltrate your van.

Toilet chemicals are almost all bad for the environment (there are a few exceptions that we sell at Caravan RV Camping) and over time, the cost can really add up. Plus, they take up valuable space in your van.

The SOG system avoids all of this by simply removing the smell by natural ventilation.


  • 100% chemical free – no need to buy chemicals when travelling

  • 100% odour free

  • Low power consumptions – just 0.43 watts

  • Any supermarket branded toilet paper can be used because you are not relying on chemicals to break it down

  • Great for off-gridders and tiny homes

  • SOG adapters are designed to suit all 12v caravan toilets, including Thetford and Dometic cassette toilets,and even some permanent black tanks

  • Low running costs as you don’t need chemicals or special toilet paper

  • Emptying the tank is easier as the contents are more decomposed

  • Made using innovative German engineering


  • You need to replace the filter once a year (but the Roof model is maintenance free!)

  • You need to install the system – but it is a simple DIY job



What Caravan Toilets Is A SOG Toilet System Compatible With?

SOG adapters are designed to suit all 12v caravan toilets, including Thetford and Dometic cassette toilets, and even some permanent black tanks.

Choose from standard side, roof or floor venting models designed to match your existing cassette toilet.

Use this diagram to find the right match for your toilet:


Still have questions? Give one of our friendly team members a call on 1800 787 278!

DISCLAIMER* Please note, this advice is general in nature and we strongly recommend consulting the product manual and where relevant, a professional installer.

Comments (6)

SOG System

We installed the SOG a couple of months ago, so far it’s everything they say about it. Easy to install and no smells, even on really hot days. We no longer need chemicals, all we put in our toilet is our waste. Very happy with this system.
By: Andrew on

www.caravanrvcamping.com.au Response
Hi Andrew, fantastic feedback. Thanks for taking the time to reach out

What keeps the sewerage from sloshing up the vent

What keeps the sewerage from sloshing up the vent? previously you have stated that this would not be a problem however this has happened twice since fitting the sog to our C200 toilet, the Tank. it's a problem that I'm totally unable to resolve.
By: Lyndon Cook on

www.caravanrvcamping.com.au Response
Hi Lyndon, it is recommended to empty the cassette prior to travelling. If this is not feasible then we would recommend disconnecting the hose in transit and using a pressure valve/plug. Once you have arrived you connect the system back up.

What keeps the sewerage from sloshing up the vent

What stops the liquid from sloshing up the SOG vent-pipe and blocking the vent opening/filter or even running down the outside of the cassette door? There doesn't seem to be any baffle or valve. We have all seen how much a cupboard contents can move around if a cupboard door is left unsecured.
By: Rod Mott on

www.caravanrvcamping.com.au Response
Hi Rod, as they are fitted to the top of the tank and the hose is directed up, it prevents any backflow up the pipe. This won't be a problem

Roof model is maintenance free!

Can you explain why the roof model doesn't need the filter replaced please.
By: Keith Lewis on

www.caravanrvcamping.com.au Response
Hi Keith, the filter on the side wall installation is to help prevent smells coming directly out and sometimes in to the outdoor living area. The roof vent pushes smells up and away from your van so the filter is not needed

Cassette with flushing hold tank

Is there a SOG with a flush hold tank?
By: Vivian Warke on

www.caravanrvcamping.com.au Response
Hi Vivian, the SOG systems are based on the model of toilet you have. These are specifically designs to suit the type of cassette you have. The Flush Tanks doesn't require a SOG as it is fresh water

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