monitoring RV water tanks

In Australia, those of us who live in big cities and towns tend to take fresh water for granted. Unless, of course, there is a serious drought happening, at which time we all pay a bit more attention. And it’s a bit the same with our RVs. No matter whether we’re buying a caravan, a camper trailer, or a motorhome, we expect it to come fitted with water tanks to supply us on the road. And most of us don’t give it any more thought than that.


But there are actually a few different types of water tanks and it pays work out in advance what type best suits your needs. The most common variety is made from high density polyethylene and has a capacity in the range of 80-90L. Most on-road caravans and motorhomes would come with this type; usually one tank for RVs without a bathroom, and two tanks for those with a shower and toilet.

Some rigs, particularly those designed for remote travel, will come fitted with extra caravan water tanks as standard. Although economic to buy, polyethylene tanks have the disadvantage of being vulnerable to stone and rock damage and, therefore require either ply timber or galvanised sheet protection.

It is for this reason that many specialist offroad caravan and camper trailer manufacturers fit their own custom-made, roto-moulded water tanks. In addition to the extra strength that roto-moulding offers, it also means that the caravan water tanks can be specifically designed to fit perfectly under the chassis. And then a few RV manufacturers use aluminium water tanks instead.

All water tanks can be used for storing grey or fresh water, however, grey water tanks as standard are still quite a rarity in the caravan and camper trailer market, while nearly all motorhomes and fifth wheelers have them fitted at manufacture.


With weight being a prime consideration for most RVers, it’s worth remembering that every litre of water you carry takes a kilogram off your allowable payload. For example, a caravan with two full 90L water tanks will lose 180kg, or nearly half, of its 400kg payload.


Water is a precious commodity, particularly if you’re travelling in outback Australia, and it’s imperative to know just how much water you have on board your RV at any time (especially if you don’t travel with full tanks because of weight or sway issues). Water tank monitoring has not always been an exact science, with lots of room for error, but a new product by BMPRO aims to take the guesswork out of it.

The BMPRO Dipper digital water level indicator is designed to be used with both fresh and grey water tanks, and can be used in conjunction with BMPRO’s Trek and Drifter battery monitors. It is also compatible with other monitors, and while it can be fitted to any new RV during manufacture, it is also an easy retro-installation into existing plastic and metal tanks. All you need is is a 22mm hole in the side of the tank. In contrast, some van manufacturers still use a series of water sensors plugged in with silicon.

The Dipper comes in three different cable lengths – 2.5m, 5m & 7.5m – all fitted with a five pin waterproof connector, so no extra wiring through the RV is necessary. The Dipper is designed to be very accurate, making assessing water tank levels, the need to fill-up, and payload calculations easier than ever for RVers.

Do you suspect your caravan monitoring system gives you incorrect water tank reading? – Your water tanks may need some attention. Check our tech tips on how to clean, empty and maintain water tanks.

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