Eleven million litres, 38 per cent losses, and 240 tankers a day
Ward 14 of a municipal corporation has 1.2 lakh residents. At the design norm of 135 litres per capita per day the ward needs about 16 MLD, but it receives 11 MLD, delivered from a reservoir 22 km away on alternate days for about 45 minutes, at a pressure that reaches only ground-floor taps in the higher lanes. Non-revenue water is estimated at 38 per cent: 12 per cent leakage and 26 per cent unmetered or unmetered-flat connections. About 9,000 households buy tanker water in summer at Rs 800 per 5,000 litres, and 240 tanker trips enter the ward on a peak day. The ward sits over a semi-critical aquifer whose water table fell 6 m between 2015 and 2023. The corporation proposes a new dam 40 km away: Rs 380 crore, five years, 12 MLD. Its engineers also offer a distribution rehabilitation package: Rs 45 crore, two years, bringing non-revenue water down to 18 per cent.
1. Which package should be sanctioned first? Show the arithmetic and state the assumptions it rests on.
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Start with what the ward actually consumes. At 38 per cent non-revenue water, 11 MLD put into the network yields about 6.8 MLD of billed water. At 18 per cent, the same 11 MLD yields about 9.0 MLD - a gain of 2.2 MLD for Rs 45 crore, or roughly Rs 20 crore per MLD, in two years. The dam delivers 12 MLD for Rs 380 crore, about Rs 32 crore per MLD, in five years, and adds pumping and treatment costs on top.
So rehabilitation is cheaper per unit, faster, and reduces energy and burst frequency; it is the no-regret move and should be sanctioned first. But it does not close the gap. Nine MLD at 135 LPCD serves about 67,000 people against a population of 1.2 lakh; even at a realistic 100 LPCD it serves about 90,000. So the honest answer is sequencing, not substitution: rehabilitate now, with a decision gate for the dam at year two.
Assumptions to test before committing: the 38 per cent figure is an estimate, not an audit, and may be wrong in either direction; the dam's firm yield in a low-rainfall year and whether its catchment is already allocated to irrigation; and whether the 135 LPCD norm is the right target in a semi-critical aquifer area.
2. Analyse the equity and health burden of tanker dependence, and propose one intervention that could show results within twelve months.
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Tanker water at Rs 800 per 5,000 litres is Rs 160 per kilolitre. Municipal supply is typically an order of magnitude cheaper, so the poorest households pay the most per litre for the worst quality. A household buying 150 litres a day through a 150-day summer spends roughly Rs 3,600-4,000, which is a large share of a casual worker's seasonal income - and households that cannot pay it do not buy less water, they buy from the cheapest informal source or store what they get in open drums. Intermittent supply plus open storage is the standard route to faecal contamination, and the burden of queueing and hauling falls mainly on women and girls. Those at the tail end and on higher lanes, who already get the least pressure, pay the most.
One intervention with a twelve-month result: convert one hydraulic zone to continuous, metered supply, with household meters and public standposts at the tail end, and regulate tankers in the same zone with metered delivery and a notified rate. Continuous supply removes the need for open storage and makes leakage visible, and metering gives the corporation its first real consumption data - the audit it needs anyway. Verify with zone-level NRW, hours of supply, tail-end pressure, tanker trips and a household water-quality sample set before and after.
3. What performance measure would you hold the corporation to over three years, and why not litres per capita per day?
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Litres per capita per day is a design norm and a useful planning target, but as a performance measure it is easily gamed: it counts water put into the network, not water delivered to a tap. A corporation can raise the LPCD figure by pumping longer while the tail end stays dry, and the residents respond by buying tankers - the number looks better while the service gets worse.
I would report a small dashboard with one headline: non-revenue water as a percentage, from a metered audit, not an estimate. Around it: hours of supply per day and the pressure at the farthest point, share of households with a metered connection, tanker trips per day in summer as a proxy for failure, cost per kilolitre delivered, and the number of days in the year when the ward's supply fell below a stated minimum. Each should be published monthly by zone, because averages across a city hide exactly the tail-end failure that matters.
Three years is about the right horizon: one year to install meters and fix the audit, one to bring NRW down, one to show continuity holding through a summer, which is when the system is actually tested.