Motorhome grey water tank cleaning: 6 simple steps

New to motorhome greywater tank cleaning? There’s no need to stress! Your tank can be sparkling clean in just 6 easy steps.

The grey water tank on a motorhome collects all the wastewater from the sinks and showers (but not the toilet - this waste is collected in the black water tank). It’s important to clean your motorhome’s grey water tank frequently to prevent foul smells and clogs that can cause the wastewater to backup.

Follow along with the motorhome greywater tank cleaning instructions below and you’ll be muck-free in no time. Plus, we’ve thrown in a few handy motorhome tips for beginners that will help you prevent problems with your grey water tank in the future.

Motorhome greywater tank cleaning: 6 simple steps

1. Choose a cleaning product

You can only use certain products to clean your motorhome's grey water tank. Some products such as bleach are too corrosive and may cause permanent damage to the tank. Whilst the cleaning products listed below are widely used by motorhome owners around the world, always read the owner manual for your specific model of motorhome and double-check which cleaning products are suggested for the grey water tank.

Products that people regularly use for cleaning their motorhome grey water tank include:

• Special detergents: Many camping stores sell detergent that is specifically designed for cleaning grey water tanks. Refer to the instructions on the bottle for mixing measurements.

• Dishwashing liquid: Many motorhome owners use a simple solution of dishwashing liquid and warm water when cleaning their grey water tank. Mix 1 cup of dishwashing liquid with at least half a tank of water.

• Napisan: Some people use Napisan as another affordable and easy product for cleaning their motorhome grey water tank. Mix 2 tablespoons of Napisan for every 10 litres of water.

• Vinegar or lemon juice with bicarb soda: Others use vinegar or lemon juice as a highly affordable and acidic cleaning solution. Simply mix one cup of vinegar or lemon juice with one cup of bicarbonate or baking soda for every 100L of water.

2. Add the cleaning product to your grey water tank

Fill your motorhome's grey water tank to be ½ to ¾ full of clean water. Then add the appropriate mixture of your chosen cleaning product.

3. Take a long drive in your motorhome

Once your tank is loaded with the water and cleaning solution, it’s time to take your motorhome for a drive (at least 1 hour). As you drive around, the solution will slosh around in the grey water tank and wash away the grime and muck that’s stuck on the walls and sensors.

Once you’ve finished driving, try to allow the cleaning solution to sit in the grey water tank for 24-48 hours. This will allow it to further erode any buildup before draining the tank.

4. Drain the grey water tank

Drain your grey water tank as you usually would at a dump station. Learn about the rules for dumping waste in New Zealand with our motorhome camping guide. And use these waste disposal resources from Tourism Industry Aotearoa for help finding a dump station near you.

Connect one end of your sewer hose to the dump station hole and connect the other end to the valve on your grey water tank. Then open the grey water tank valve and the cleaning solution should flow out. If it does not flow out easily, please see this easy DIY solution to clearing a clog in your grey water tank.

It’s best to empty your grey water tank after emptying your black tank, as the greywater will wash out any black tank residue left in the sewer hose.

5. Rinse the grey water tank

Once the grey water tank has fully drained, it’s best to rinse the inside of the tank with clean water to wash out any remaining residue. This will help to prevent foul smells.

Whilst you can try to rinse out your grey water tank with a simple garden hose, this can get messy and you may not reach all corners of the tank. Instead, you might prefer to attach a flush valve to your grey water tank valve. Then attach your garden hose and sewerage hose to the flush valve. The flush valve will shoot water all around the tank and you’ll be able to see the water run clean when the tank is fully clean.

Alternatively, your motorhome's grey water tank might already have a tank rinser installed. Similar to a flush valve, attach your garden hose and sewerage hose and wait for the water to run clear.

6. Add treatment to the grey water tank

Although your motorhome's grey water tank is now clean, it’s always best to add a treatment afterwards. This will help to prevent foul odours and clogging.

Greywater tank treatment products come in both liquid form and drop-in tablet form. Follow the instructions on the packet and use an appropriate amount for the size of your tank.

How to prevent motorhome grey water tank problems

Experiencing clogging and/or foul smells in your grey water tank? To avoid these issues, all you have to do is follow some simple tips and tricks:

• Install sink strainers in the sinks and shower in your motorhome. This will prevent food waste and hair from entering and clogging your grey water tank.

• Scrape the waste off your dishes into a bin before washing them in the sink.

• Try to use the bathroom and kitchen facilities provided at the campsite as much as possible.

• Always empty the grey water tank entirely, particularly when storing your motorhome away for a long time.

Hire a motorhome in New Zealand

Now that you know the ins and outs of motorhome greywater tank cleaning, you’re one step closer to being ready to hit the road. Still, need to find the perfect motorhome for your adventure? Check out your options for motorhome hire on the North Island and South Island today!

Camplify enables holidaymakers to quickly search through privately-owned rentals. Simply enter your pickup location, adjust the optional filters (such as toilet and shower) and within seconds, you will find the perfect motorhome for your holiday around New Zealand!

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