The dos and don’ts with the grey water controversy

ByMarty LedwichAugust 10, 2020
The dos and don’ts with the grey water controversy

Just because it goes down the sink doesn’t mean it’s harmless. There are ways you can be a water-wise camper and not be in a grey area! Here are the dos and don’ts with grey water.

I have a confession to make. I’ve never really understood what the big deal was with grey water. As far as I was concerned, any water that gets soaked into our parched earth has got to be better than tossing it down the drain. But for many caravanners, that’s the last place grey water should end up.

It just seems whenever the subject of grey water is raised online or around a campfire, it turns into a real battle, such is the level of emotions the subject seems to arouse. I just couldn’t understand it.

Then we started living full time in our caravan and I started to notice a few things. Smells from drains, grey water from other nearby campers, and it compelled me to look into the grey water issue a bit further. As a result, I’ve had a rethink into my attitude and it’s about time all of us did the same.

What is grey water?

Grey water is essentially any domestic wastewater that doesn’t originate from a toilet. That includes wastewater from washing machines, kitchen sinks, bathroom sinks and showers. Waste that originates from a toilet is called black water. In a domestic or household environment, it is possible, and often desirable, to divert grey water onto our gardens and lawns. Depending on how your household plumbing is arranged, you can select exactly what wastewater source to divert. In a caravan or motorhome, that is not generally possible.

Flushing through your grey water system

Why is it a problem?

Probably the biggest issue with grey water is that it doesn’t stay grey for very long. Whether you have a grey water tank or not, any grey water that is stored or remains in the plumbing of your RV, will turn to black water within 12 to 24 hours. Maybe even quicker in the heat of the Australian summer. This is due to the growth of bacteria that starts off in medium concentrations but multiplies rapidly in the warm and confined conditions.

Read next: The unpleasant truth: Grey water, it’s not black and white

Other organic material such as dead skin, hair and food scraps, add their own bacteria and act as food at the same time. This material can get trapped in the bends and crevices of the plumbing causing noxious smells to develop and, depending on where your grey water hose runs off, can make life for your neighbours quite unpleasant. There may also be some chemicals in your grey water, such as soaps and cleaning products, that may be harmful to the environment.

grey water tank under a Roadstar caravan

Storing grey water

Many campsites require RVs to be fully self-contained. That normally means the ability to store grey water until such time as you leave the area. To store grey water, you will need a tank of some description. Most modern caravans and motorhomes are being equipped with inbuilt grey water tanks that are integrated into the plumbing. Many function by diverting the flow from the grey water outlet into the tank via a manually operated valve.

Alternatively, many owners choose to retro fit a tray water tank to their RVs while others use an external portable grey water tank. Some are nothing more than a large plastic bottle that collects grey water flow from the outlet while others are purpose designed and have trolley wheels allowing the wastewater to be easily transported to a disposal site.

If you’re using an external or portable grey water tank, it is worth checking to see if the design conforms with the definition of self-contained for the particular campsite you’re intending to visit. Many only allow integrated grey water tanks.

Disposing of grey water

This is where the issue becomes somewhat contentious as the rules may vary depending on where you are or even the conditions that exist at the time. Whatever you do, it’s illegal to dump grey water onto the road as you drive. In any sense, it’s a terrible look for RVers to display to the general public, but your load, liquid or solid, legally stays inside your vehicle. If what you’re dropping is now black water anyway, it’s going to end up in a waterway somewhere, and the EPA doesn’t approve. You may argue that it’s diluted but you’re splitting hairs and displaying your attitude to the topic. Don’t drop it anywhere but a drain or where directed to on private land.

A caravn park drain blocked with leaves

At Caravan parks

As a rule, most caravan parks will provide a grey water drain where visitors can direct their grey water using their outlet hoses. Some are purpose-built drains into which the grey water hose outlet is inserted. Others may be no more than an open drain in which the grey water hose outlet just sits.

You will also find many caravan parks do not provide a grey water disposal system and, instead, they may simply request you to direct grey water onto the grass or garden surrounding your site. We find it is a good idea to check with the park reception as to how they want their guests to dispose of grey water. If they are in drought, they may prefer your grey water to flow onto their gardens rather than down the drain.

At free camps

It would be extremely rare for free camping areas to provide any disposal systems for grey water. Unless they are signposted otherwise, grey water can be allowed to run onto the ground. In these cases, you need to be very considerate of other campers in your vicinity and place the grey water hose outlet in such a position that it doesn’t affect anyone else around you. (You should apply the same courtesy everywhere really.)

Using an RV dump point

Stored grey water

If you have a grey water tank and it is full, you’re going to need to dispose of the contents. As we saw earlier, stored grey water doesn’t stay grey for long and it is best considered and handled as if it was black water. That means storing it until you reach a public dump point. That is the best way to dispose of stored grey water.

A caravan park needs safe water practices


There’s no way we can magically convert our grey water into clean drinking water, but we can make it less offensive and better for the environment.

  • Choose septic-friendly products such as soaps, detergents and washing powders
  • Keep your grey water systems clean
    • Pour vinegar and baking soda down drains to clean them
    • Flush grey water hoses after each use
    • Use commercial grey water tank cleaners regularly
  • Filter out all solid matter and dispose of it with your regular rubbish
  • Don’t use your RV shower as a toilet
  • Dry-wipe plates and eating utensils with paper towels before washing-up

So now you know the dos and don’t with grey water, you can travel safe in the knowledge that you’re doing the right thing!