What does being eco-friendly have to do with overhead water tanks? While our immediate response may be ‘nothing’, it's time to rethink the answer, says architect SATHYA PRAKASH VARANASHI
Today, most tanks are made from synthetic plastics with high embodied energy, produce much waste in production, cannot be cleaned easily and heat up the water during the summer afternoon just when we need cool water. The traditional brick water tanks have solid concrete roof with all the strength and security of concrete which is not required for water tanks. Often tanks are so small that frequent pumping up become a necessity or they are too large with stagnant water. In many such ways, we are not getting the best from overhead tanks.
For a small family of four, we do not need more than two days’ supply of approximately 1,500 litres atop the house. The water consumption per person per day is around 150 to 200 litres, so in case of large storage capacity, daily replacement will be small, leaving the old water in the tank. Instead of the RCC roof top, we can have a metal sheet lid framed in M.S. angles that can be lifted up like a car bonnet. This drastically reduces the cost, makes the job simple. Most people do not periodically clean the tank, for it’s a cumbersome procedure, so the lid concept eases it out.
If the tank is placed in the corner of the building, we get two edge supports and can save on structural cost with a diagonal beam. To get the water pressure for solar water heaters, we need a minimum height of 6 ft., which can be further raised to get 7 ft. underneath the tank. By a small extension of the tank slab, we can actually get a small room underneath for storage, stay, study, wash, pressure pumps or as may be needed. On the cost front, this room would come at a nominal extra cost, but contribute to varied activities on the terrace.
Taking fewer large diameter pipes and then branching them off into multiple taps instead of taking a separate outlet pipe for every tap is another measure to save on plumbing. Replacing G.I. pipes by the new generation pipes has decreased the need for repairs. Being a manufactured and marketed product, the PVC tanks have surged ahead of traditional brick tanks in popularity, though they come with numerous problems. The only possible problem with brick tanks is seepage due to bad workmanship, which can be mitigated by some attention. Plastering the inside with chicken mesh eliminates the seepage, while anti-fungus paint keeps it clean. Water in a brick tank stays cool and is any day healthier.