Should you travel with water tanks full or empty?

Article by RV Daily

Out of all the issues that caravanners argue over, the question of full or empty water tanks while travelling is one I’ve never fully understood. As far as I’m concerned, if I needed water at my next camping destination, I’d fill my tanks. Otherwise, I’d travel with them empty. But some people have very strong opinions on both sides of the fence. So, this month, we take an in-depth look at the question and discuss the pro and cons of travelling with your water tanks empty or full.

REASONS FOR HAVING THE WATER TANKS FULL

Stability in windy conditions

Having your water tanks full puts a lot of weight down low in the caravan, lowering the centre of gravity and, supposedly, increasing stability. This is particularly noticeable when driving in windy conditions. Some sections of the Bruce and Pacific highways (in the east) are prone to substantial crosswinds and are notorious for caravan rollovers. Whether or not these are all caused by the wind is debatable however, having additional weigh down low will make the caravan less susceptible to severe crosswinds.

Good quality water supply

Water quality varies across the country. Some places are blessed with great tasting and clean water straight out of the taps whereas other places don’t. The reasons for poor quality water are varied but among the usual suspects are a bore water supply, old water pipes or drought conditions. By travelling with your water tanks full, you’ll always have a supply of good drinking water available.

Keeps your options open

If you’re the sort of traveller that doesn’t like to plan your trips too much, you may want to give yourself the option of stopping overnight at a free camp rather than keep driving on to the next caravan park. Free camping without water is no fun so having a supply on board at all times means you can pull up for the night anywhere you like and have a shower if you so desire.

TRAVELLING WITH THE WATER TANKS EMPTY

Less weight means better fuel economy

There’s no escaping the fact that carrying more water means you’re towing a greater weight and, the more weight your tow vehicle has to pull, the more fuel it will use. All tow vehicles are different, but I have noticed our Toyota LandCruiser 200 Series will use an additional one litre of fuel per 100km for every 100 litres of water we have onboard. It doesn’t sound like a lot, but over time and distance, with a possible 270 litres of water on board, we certainly notice the difference at the fuel bowser.

Less wear and tear in the tow vehicle

The more weight the tow vehicle has to pull, the harder it has to work and that results in greater wear and tear. You may find you will need to do more frequent oil changes when towing especially with the constant need to pull the extra weight of full water tanks. Transmissions also work harder with the additional weight and they may require more frequent servicing as a result.

Less wear and tear on the van’s suspension

The vast majority of caravans have fairly basic leaf spring suspension. The constant movement in the springs develops friction between the leaves, which causes them to wear out over time. Adding to their workload by keeping your water tanks full means these springs work harder and can wear out much quicker.

Less cargo capacity for other items

Most tandem-axle caravans will have a cargo capacity of anywhere between 400kg and 600kg. If you have two 90-litre water tanks and you fill them up every time you hit the road, there’s 180kg of cargo gone, and you haven’t stored a single personal item inside the van as yet. The situation could be worse with single axle caravans.

Instability issues

I often hear caravanners saying that their vans are unstable when the water tanks are empty, therefore they always travel with the water tanks full. They will sometimes get this advice from the caravan manufacturer. A well-designed caravan should be stable regardless of how much water it is carrying.

If you find that your caravan is unstable with empty water tanks, regardless of the prevailing weather conditions, you probably need to look at how other items are stored in it to ensure you haven’t incorrectly distributed the load. Either that or your caravan has a serious design flaw and needs to be checked by a qualified caravan repairer.

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Comments 6

  1. I hear this “extra stability” theory espoused all the time. I would like to see the actual science on this. Adding 180kg to a 2.5 to 3.3 ton van, will shift the centre of gravity and centre of pressure of the van a minimal amount.
    I have been towing vans for 38 years, 21 to 23 ft reasonably heavy vans, and believe that if you have your tow vehicle, hitch, WDH and van set up and loaded correctly, whether the tanks are full or empty makes little difference.
    There may be a greater impact on vans of lesser weight, but they usually don’t carry as much water, owing to lighter payload restrictions.
    Incorrect loading of caravans, poor setup of the hitch and miss match of the van and vehicle, are the prime causes of most mishaps.

  2. In my opinion I believe water tanks should empty when travelling. More weight from water will cause everything to work harder from tow vehicle (fuel / service intervals ) to caravan suspensions working harder regardless of whether they are rocker roller or independent suspensions. Shock absorbers should be fitted to all vans as standard. Water tanks in our caravans do not have baffles in side them to minimize the risk of water being thrown about in the tank. If the water tank is always full or nearly full (two 90 litre tank equals to 180kg of moving weight) which in itself can cause or make the van even harder to control if it should begin to sway. A half empty tank will cause water to travels from one side of the tank to the other. I have spoken to a number of fellow travelers who claim that their caravans tanks have baffles in them ?????? . Yes anti-sway control in the van will assist to mitigate the problem this item should also be a Standard Requirement. Caravans builders should be better regulated to meet a certain level of safety standards just as the vehicles we drive meet ADR standards in Australia.

  3. last year I got cut off by fires for 3 days with no access to water. I was then cut off on the Nullabor for 5 days with no access to water., A month later I was cut off by flood waters after a cyclone up north for 7 days.
    Travelling with full tanks is a no brainer.

  4. I have a 21 ft van tare 2118kg ball weight 110kg and loaded as well as possible ball goes up to 120kg loaded with water goes up to 160 kg and is a far more stable van to pull. so will always fill when traveling, extra 1l liter per 100 a small price to pay

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