Shivaratri traditionally marks the end of summer in the south. In the north they believe Holi is the marker. As summer breaks, one vehicle which will make more and more of an appearance will be the water tanker.
Shortage of water in the city utility lines means the demand for water from these private tankers shoot up. Drawing water generally from borewells, they scurry about in the narrow lanes, stopping a while and letting the water flow into sumps or with a motor, pumping it to overhead tanks.
Water sloshing about on the roads is also a common sight with these vehicles. Why is it so ? For one, water is quite a corrosive substance especially if it comes with high dissolved oxygen when pumped into these steel tankers. That is why on the insides a coat of EPI is applied. This prevents rusting and leaks. The EPI coating has to be done every year if a water tanker is to be in good shape and to prevent rust from appearing in the waters they supply.
Next is the vehicle itself. It is no joke to carry water in a vehicle. One litre of water weighs a kilogramme and carrying 6,000 litres of water casts a heavy burden on the vehicle, the tyres and the driver. Vents are therefore provided to take the pressure off when the tanker moves on around a curve, throwing the weight to one side. A little bit of water from these vent pipes will slosh around.
The most important reason for the leakage is of course the valve or valves which when connected to a hose pipe dispense the water. If not made by a reputed manufacturer and if not welded and attached properly, they can leak. Fortunately, many good valves are coming into the market and things should improve on this front.
Finally, the tanker operators can buy clamps with the large hose pipes they carry to transfer water to sumps. A clamp-based pipe can be locked together more easily and not just tied with a rubber strip, thus preventing leakage.
Design has an important role to play in all of these. As they say, God is in the details and when water becomes scarce and godlike, better to pay attention and prevent its waste. That would be water wisdom.
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