QUESTION
Water leakage from overhead tank or supply/distribution lines in house in Chennai,TN - Need help with this issue

Hi,

I live in a 12 apartment building in Chennai. We get water from 3 sources: Metrowater, a borewell and a rain-water harvested well. Water from all sources is pumped up through 3 different pumps to an overhead tank. This is partitioned into two: a smaller tank for Metrowater (3500 liters or thereabouts) and a larger tank for water from the other sources (7000 liters).

There is a provision by which water from the Metrowater tank - the smaller tank - flows into the larger tank once it reaches an optimal level. Distribution lines come down the full length of our 4 storey apartment, go underground and then come up, and at appropriate points there are supply lines to bathrooms and kitchen in each apartment. For the last week or so, we have not been able to retain water in the overhead tank - and we suspect a leak.

We conducted a simple experiment to find out if indeed there was one: we pumped up water, shut the wheel valve to the main distribution line, requested people not to open their taps, and filled the overhead tanks. With no water being distributed, yet the water level in the storage tank came down at the rate of about 12 cms per hour.

We are trying to contact our builder for a plumbing map - since the distribution line goes underneath and then comes up to branch off to each apartment, it is going to be difficult for us to check for leaks. We don't understand why the builder had to take the distribution lines underneath in the first place. And now we are looking for ways to identify the leak, and maybe relay the distribution lines, so that if there are leaks in the future we are aware of the same - that is we plan to realign the distribution lines, by making them run overground.

Please let us what would be a valid approach to addressing this problem.

by
18 February 2013