Guide to Water Treatment for Your Rig

Scott Heiman — 29 May 2017

We’ve all heard of the odd dead possum or cane toad in outback water tanks. And many of us know about the risks of water contamination from industrial and agricultural run-off. So it makes sense to ensure that we fill-up from clean water sources when we’re on the road. But how much care do we take of our rig’s on-board water storage tanks between trips?

Whether we use our rigs and associated gear often or just ‘once in a blue moon’, sediments, fungus, bacteria and algae can build up in our water tanks. Even with a new setup, industrial dust and other contaminated residue like pollen may have settled in the tank during installation. And if we’ve bought our rig second-hand, there’s simply no way to know what we may be inheriting. Any one of these scenarios has the potential to ruin a family holiday – and if we’re travelling in remote areas, the risks are compounded.

Relying on the chroline in ‘town water’ every now and again won’t cut it, as the concentrations are unlikely to kill the bacteria, and its volatility causes it to dissipate a day. So what can be done?


It’s easy to see why our routine maintenance regime should include flushing our main tanks, jerries and bladders at least once a year. And it’s easy to achieve too. Just disconnect the water filter (if you have one) and by-pass it so as not to clog up the filter as you take the next step… Now, turn on all your taps and shower outlets and let three-quarters of the water drain out of your tank. Leave the last quarter in the tank and go for a bumpy drive to stir up the remaining sediment. Then fill up the water tank before opening-up all the outlets again. This time, empty the tank entirely to flush out stale water leftover from your last trip. Meanwhile, clean out your water filter and replace the old medium with new.

Do the same with your jerries and bladders – giving them a good shake if you can.


The ‘clean and purge’ routine is a minimum requirement. But other measures are also available when you’re pursuing a clean water source. Some of these approaches involve getting in touch with our ‘inner scientist.

Many swear by the value of homemade cleaners using substances like white vinegar, bicarbonate of soda or a bleach solution.

So we thought we’d have a closer look:

Vinegar: This is a good cleaner but not a very effective sanitizer. A study by the Colorado State University lists it as effective only against salmonella at room temperature, and not effective against E. coli and a range of other water-borne nasties. The recommended ratio of vinegar to water varies from 5 to 25 per cent depending on what you read. With a 100L on-board water tank, 25L sounds like a lot of vinegar – to do half the job. So we reckon we’ll reserve this condiment for hot chips.

Bicarbonate of Soda: The same study showed that bicarbonate of soda (or sodium bicarbonate, an alkaline salt) is not an effective sanitizer at any temperature or time. It’s true that bicarb can help combat fungal growths and get rid of stinky smells. But it pays to beware. If your water tank has been previously treated with other additives or is otherwise contaminated, you may create additional salts that will make the water even less suitable to drink and which may also corrode your pump and fittings. We recommend leaving this option for wiping down your fridge.

Bleach: Bleach is well known for its sanitation and cleaning properties. Trouble is that it contains chlorine which can react with organic matter that’s already in your tank. This matters because the chemical reaction creates what’s called trihalomethanes, which studies indicate may be Carcinogenic. Bleach can also react with the metals in the dirty water to create salts and acidic water – and neither you, your travel party nor your rig’s plumbing will benefit from this. 

For these reasons, we’d generally steer clear of using bleach as a disinfectant – unless you’re absolutely sure that you know what you’re doing.


The Colorado study suggests that hydrogen peroxide could be better. This chemical is available as a liquid and works like a bleach and an anti-bacterial agent, without their nasty side-effects. Specifically, hydrogen peroxide won’t mix with organic sludge in our water tanks to form toxic compounds and is 100 per cent biodegradable. It has been used as an antiseptic since the 1920s as it kills bacteria by destroying their cell walls.

Hydrogen peroxide is found in water purifiers like the Biomagic WaterPure range. In these products, hydrogen peroxide is combined with silver ions to ‘soften’ water by removing other metals within it. Developed for industrial and domestic kitchens, BioMagic Tank Sanitizer is now available for use in RVs.


Your water tank has an air hose. When the water goes out, this air intake ensures that it’s replaced by air. Otherwise a vacuum gets created and the water stops flowing.

So here is a test. Get a clean wash cloth and attach it over the air intake with a rubber band before you next head out on the tracks. Chances are that it will soon get encrusted with dust and dirt. This is the same dust, pollen and exhaust residue, .etc, that gets drawn into your water tank as you travel. The image on the left shows the dust ingress gathered after just two weeks on the road. So... do you still think the water in your water tank is clean?

So what can you do? A simple in-line filter works great as a dust filter for your water supplies, which you can fit close to your tank’s hidden air inlet, as shown above.


Remember to have a designated (sole use) feeder hose for your camper. Dual purposing your home garden hose is not a good idea. Left lying around in the garden in the sun everyday, the hose will degrade and taint the water that runs through it.  And it’s likely that any water that’s been lying around in the 20 metre hose length in the sun will also taste rotten. So, save the garden hose for washing the rig and playing with the kids.

For drinking water, you can do a lot better. We like the Flat Out drink water hose. It’s a scaled-down fire hose with a food grade liner. Non-tainting and made from 100 per cent polyester, the hose squashes out the water as you reel it in – and it takes up a fraction of the space of a standard hose. Quality brass fittings prevent corrosion.


Water filters make a huge difference to the quality and taste of the water we use and there is a huge range available. We like the BioMagic 0.5 in-line filter which we use to filter water before it even enters our rig’s water tank. The filter is made of 100 per cent coconut carbon and silver ions. The coconut carbon (charcoal) filter removes the chemicals that cause nasty tastes and odours. It also removes a wide range of organic compounds and most disease-laden micro-organisms from the water. Meanwhile, the silver ion component reduces water hardness caused by traces of iron, manganese and other metals in the water. This means that the water simply looks better and tastes better.

Now, we’ll drink to that!

Ultimately, whatever our approach, we must remember ‘water is the stuff of life’. Just as tainted water goes foul in a teacup by the sink at home, so too will our tank’s supplies without our attention. And what’s more important than clean water on a trip?

So, isn’t it time you asked yourself – “When was the last time I purged and cleaned my rig’s water tank?”


guide water technical