Caravan Grey Water Tanks; do you really need one?

Caravans have come a long way over the years, and a lot of them now come factory fitted with grey water tanks. What is a caravan grey water tank for for, and do you actually need one?

Australia is going through a fair bit of change when it comes to dealing with grey water from caravanning and camping, and its important that you do the right thing for the environment, other people and to avoid a nasty fine or being turned away from a camp site.

A Grey water tank allows you to comply with the fully self contained arrangement that some places are now asking for in order to camp there.

I say some, because the reality is the large majority of Australia does not require you to contain your grey water.

Caravan Grey Water Tank
Do you actually need a Caravan Grey Water Tank?

What is grey water?

In terms of camping, grey water is the water you consume that comes from doing your dishes, having a shower, washing clothes and washing your hands.

This means its usually got soap, food scraps, oil and other bits and pieces in it. It does not include anything that goes down your toilet; this is known as Black Water and is a whole different kettle of fish.

Cleaning the dishes
Grey water is any water generated that doesn’t go down the toilet

Storing grey water

As mentioned above, grey water tanks are becoming quite common, and popular on caravans and hybrids, and are generally 60 – 150 litres. Any water that goes down the sink or shower, ends up in the grey water tank, and then the idea is that you empty it prior to arriving at the next camp.

Often your grey water tank is no where near the capacity of your fresh water tanks, so there’s some juggling to be had, or you need to empty it mid way in a responsible way. Alternatively, you let it run out in a responsible way (if you are allowed to).

Grey water storage
Grey water tanks are becoming more common

Grey water changes to black water

Grey water is virtually harmless when it first leaves your sink, or washing machine, or shower. If it goes onto a piece of land in the sun, you’ve used environmentally friendly chemicals and it soaks away without upsetting anyone its probably the best way of dealing with it.

However, if you store it for more than 12 hours, it slowly turns to black water and this process is hugely accelerated with heat. If you are camping in the northern parts of Australia where it is warm, expect your grey water to turn to black water faster.

Whilst grey water straight from your dishes is probably not something you’d want to play with too much, its generally fairly clean, has no odour and when your kids jump in the puddle it creates when you let it go its not the end of the world.

Store it in some heat though, and when you release it the grey water will reek and you don’t want to go anywhere near it. This is because bugs and bacteria grow, and its turned into a form of black water.

Black water is not something you want to play with, which is where the collection and holding of grey water becomes an issue.

Grey water collection
Storing grey water makes it turn into black water. We never collect it, except for a night at Cossack earlier in the year as per the above photo

Why fit a caravan grey water tank?

Grey water tanks are fitted primarily to comply with the regulations of specific camp site regulations. Collection and disposal of grey water has been an international norm in motorhomes and campervans for many years, and its slowly rolling out in Australia.

That said, I honestly feel its a giant snowball that has occurred without people really thinking about it, because you now have dump points that are being filled with grey water that they were never designed for, and people making a far bigger deal about grey water than is actually necessary.

It seems like some councils have all copied each other and made grey water collection mandatory (in some areas, not the whole of Australia). That’s great, except you now have a huge number of people with 50 – 150 litres of grey water every couple of days that need places to dispose of it.

When they do the right thing and go to a toilet dump spot, and find that it is full because they are being hammered so much more, then what?

Is the dumping of well managed grey water as its created, in a suitable place better for the environment than having to empty toilet dump points far more often, and the environmental issues that go with it?

Dump points
Are dump points designed to take thousands of litres of grey water, along with the sewage?

Do you need a grey water tank?

In Western Australia, there are only a handful of places that require you to collect your grey water, and its most certainly not the national parks.

There are a couple of shires that have mandated it at a few sites, but in the hundreds of different camp sites we’ve been to all over WA, only one has required that we collect our grey water, and that was at Cossack (there was one more, but its since closed).

I simply took a 20L water container, and modified our sink outlet to go into it. The caretaker did come, and even checked and photographed the setup, but in my mind its all a bit of overkill.

If people got rid of their grey water in an environmentally sensible and respectful way there would be far less issues than containing it, carting it to a dump point and getting rid of it.

As we had an outdoor shower it meant we couldn’t use it for that night, but we were OK with that. If it were a longer stay, it’d be a bit more annoying.

In other states, its a different story, and grey water tanks are needed more often, but its almost exclusively in council provided RV stops. These are the free, or low cost options that some caravans and motorhomes stay at, because they are close to town, are cheap and easy to use.

These are often not the most amazing camp sites, and a huge majority of people do not use them.

There are no National Parks in Australia where you have to contain your grey water, and a major majority of paid camp sites do not require you to cart your grey water away either.

I know plenty of people travelling around this great land that don’t have tanks, and have only been turned away from a tiny, tiny number of camp sites.

Will that change in the future? Maybe. Is the environmental benefit of taking grey water to a toilet dump point any better? I’m not really sure, and I hope the rule changes and those who adopt them are sensible in their thoughts.

What changes are made as time goes on will be fascinating to see; its a lot of work for people to contain their grey water and dispose of it correctly in national parks, and other remote camping areas.

This is especially the case when you are camping, and don’t have access to a caravan or camper trailer with in built tanks.

Its important that you read the signage properly too, as self contained does not necessarily mean you aren’t allowed to let grey water out, onto the floor.

In summary, no, you do not need a grey water tank, but if you have one it can open up a small minority of camp sites. If you plan on doing lots of shire run overnight rest stops, then it might be more important to you.

Fitting a grey water tank isn’t free, and it comes with other costs, so like everything in life, weigh it up for yourself.

Fitting a caravan grey water tank

Like water tanks, its not too hard to install a grey water tank on your camper trailer or caravan. It’s a fairly uncomplicated DIY project, providing you take your time and do it well.

Carefully consider its position and size

When you install a grey water tank, there will be times when it will be full, and very heavy. This can hugely affect your weight distribution, and dramatically increase or decrease the tow ball mass, which can be a big problem.

Second to this is that if you take the van off road, it can be subject to getting hit, which is another major issue. The last thing you want to happen is to come down a rock step and have the grey water tank get ripped off, potentially damaging other gear under your trailer. 

The size of the grey water tank is hugely important too; if you have 300L of fresh water, and a 50L grey water tank, its going to cause you some issues along the way. That’s not to say you need the same capacity as your drinking water, but you need a way of dealing with the difference.

Tow ball weight
If you move water around too much your tow ball weight can change hugely

Grey water tank mounting

Water is heavy. Even if you go for a 40L tank (which is on the smaller size for a grey water tank), that’s at least 40kg of weight bouncing around, and if it comes off and hits another vehicle, its going to be a serious accident.

Not only do the straps need to be well and truly suitable to take the weight, but where you attach it to does as well. This means using proper bolts (not screws) and ensuring the structure will take the weight. Ideally you tuck it out of the way, support it well and it never moves.

Grey water tank mounting
Caravans are easy to attach grey water tanks to

Protect the grey water tank

If you do much gravel driving, you’ll find that parts of the trailer can be hugely subject to gravel rash. If its a plastic tank generally they are super thick and will take this for years without any damage.

However, if its going to cop a flogging you may need to look at a light weight guard, and installing some protection for the pipework too.

If it gets hit and breaks its not as serious as losing your water tanks, but its still an inconvenience.

Grey water tank guard
A guard around the tank is a good idea

Consider a bypass

I would seriously consider fitting a bypass to the tank, so when you don’t need to use it, you can close a couple of ball valves and let the grey water run out onto the floor (where allowed) or into a designated drain. The less you use your grey water tank the better, as they are smelly things!

Check your weights

Lastly, make sure that any changes you make keep  you well within the weight spectrum. Its so easy for people to be overweight today, especially with vans that only come with 400kg of payload, or that are incorrectly labelled on their nameplate.

When you install a grey water tank, you are going to be moving weights, which will upset your tow ball weight and change things as you consume water.

If your water tanks are up the front, and your grey water tank is down the back, you will be losing tow ball weight at a rapid rate by reducing the weight in front of the axles, and increasing it at the rear.

Make sure the drain empties everything

If you have a choice in where the drain is, and how its going to sit, make sure the drain allows every last drop out of the grey water tank. This will reduce the chance of it smelling, and means you can keep it empty, and ready to go at all times.

Can you use a portable grey water tank?

A lot of people don’t want a fixed grey water tank, and they opt to purchase or build a portable grey water tank. These are available off the shelf with wheels so you can walk them around, or you can easily build your own.

The issue with portable tanks is stopping them from overflowing, and their limited capacity. 

When you have several hundred litres of fresh water on board and only a 20 – 40 litre portable grey water tank its easy to fill it up and have no way of disposing it.

How to stop your grey water tank smelling

Grey water that is released straight onto the ground is generally fairly clean, and non toxic. I mean, you wouldn’t want to drink it, but if it was to come in contact with your skin its not going to do you any harm.

However, once its been stored for some time it becomes hazardous, and will get quite a smell.

My folks have a grey water tank in their caravan and it absolutely reeks, even after being cleaned. The drain is not located right at the bottom of the tank, which means you can never fully empty it.

Beyond this, they have no bypass, so even in a caravan park where you should be just draining straight from your shower and sink into their drain, it still has to go through the grey water tank.

How to clean your grey water tank

Grey water tanks can smell pretty bad (like as bad a sewage!), and you need to clean them out from time to time.

There’s a lot of chemicals that people will recommend, or you can buy dedicated tank cleaner and put it down the drain with the tank closed, and some water inside.

A drive around ensures that the tank gets a good sloshing around, and then you can drain it all out.

Where can you empty grey water?

Grey water tanks can be emptied at designated grey water dump points in caravan parks (usually drains near where you camp, or a larger, designated grey water dump point), along with toilet dump points if its been sitting for some time.

It’s bad practice to let the grey water out onto the road as you drive out of a camp, or to dump it anywhere near water sources. If its more than 12 hours old, you should be taking it to a black water dump site (a normal dump point).

Black water to the dump point
All black water needs to go to designated dump points

Let it out if you are allowed

If you are allowed, and you are using environmentally friendly chemicals, I firmly believe you are better off releasing your fresh grey water in a slow, respectful and careful manner than storing it and putting it into a caravan dump point.

I’m sure I’ll get disagreements about this, but I don’t feel we are at the level where everyone can be containing grey water and disposing of it at a dump site.

The infrastructure and logistics just don’t add up, and the cost (environmentally and financially) of processing the extra grey water created from camping is never considered.

Some dump points have signs saying no grey water allowed, and then you have the logistical issues where the drain of your grey water tank is often not higher than the lip of the dump point meaning it wont flow out under gravity even if you wanted it to.

That said, you should try and use biodegradable detergents, clean your dishes properly before washing them (removal of food scraps)and let the water out somewhere that its going to drain away without upsetting others.

Don’t be the fool who does two loads of washing and leaves 40L of soap and water on the floor in the middle of a big campground where it takes days to drain away.

What do we do?

We don’t have a grey water tank, and have no plans to fit one at this point in time. I mentioned above that we’ve only had one instance where we needed a tank, and we just knocked a portable grey water tank up in a couple of minutes.

We carry a couple of different grey water hoses which allows us to get rid of it in a smart way, and we are responsible with our grey water. I don’t think you need to go any further than this.

It does however, mean that we can’t camp in spots that require a grey water tank, and if it has to be fully collected, we can’t shower as we have no way of containing the water from our outdoor shower. This is one of the disadvantages of a normal camping shower set up.

Dump point in Dampier
We don’t camp where you aren’t allowed to dispose of your grey water, and just use the dump points for our toilet

What do you do with your grey water? Do you have a grey water tank? Has it restricted you at all when travelling Australia? Should we consider fitting a grey water tank?

Sharing is caring!

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *


  1. Hey Wombat,

    Yep, too many people do the wrong thing with grey water tanks, and when its been accumulating for a few days its pretty feral.

    A bit of consideration for those using the area after you goes a long way

    All the best

  2. A number of times I’ve seen wobble box owners empty there grey water tank on site the morning of departure whilst they pack up. With total disregard of the next camper, they disgustingly leave a big wet patch of putrid black water, often with vege scraps, oil, etc; Too many caravaners have the “I’m alright, fck u” attitude.

  3. Hey Matt,

    Yep, it is ludicrous, and I hate the fact that its catching on. That said, I’m pleased after 4 months on the road full time we’ve only been asked to contain our grey water once, and we could have easily gone elsewhere if needed.

    All the best

  4. Intelligent, sound information. Thank you.
    Strange how you are fine to pump secondary treated (septic) water onto your lawns and gardens, after being treated with harmful chemicals, also in local parks and ovals, but not bath and sink water!!
    Strange ideas out there I tell you.

  5. Hey Lex,

    Welcome back to the world of caravanning! You can always fit one at a later date if things keep going the way they are, but a bit of common sense works just fine for now!

    All the best

  6. Thanks Aaron for the 0n-point comments there. I am getting back into caravaning after a long break. Never had grey water tanks previously. I’ve been looking at it as I heard had there was a bit of a push for it. I think I will opt for keeping a small container just in case I have to collect the grey. Like you, I believe common sense, courtesey and a little forethought will address the issue appropriately (Pitty some of our local councils and government agencies don’t use it).

    Regards and safe travels,

  7. Hey Edward,

    Yep, it doesn’t have to be complicated. If everyone had common sense like this it would be simple!

    All the best

  8. Thanks Bronek,

    Grey water can be easily managed in a helpful and beneficial way to all!

    All the best

  9. Edward Vanderende says:

    Greet stuff!!! I can’t see what all fusser is all about, just use biodegradable soap and washing up detergent and don’t use shower a couple days. Usely there river around and usely it hot anyway , but I think I get a ported grey water tank just to make people happy. And I have,t got a tank on my caravan and travelling a lot and never had problem . Best regards Ed

  10. Bronislaw Gaca says:

    Thank you Aaron for a good, very informative article about the gray water tank, as well as many of your articles. Like you, I traveled without a caravan and there was no major problem with gray water. Now I have a caravan without a gray water container. The question arose whether you need to install a gray water tank or not? Your article helped me a lot. Luckily for me, I have had no problems so far and even some camping sites encouraged me to release running gray water under freshly planted trees or on developing grass (Barn Hill) For me it is logical and appropriate, gray water released immediately does not cause any negative effects on vegetation. Some gardeners even encourage to watering plants with gray water. I hold off installing the gray water tank until …
    Thanks Bronek