As Karnataka continues its legal battle over the Cauvery, the states capital -- almost entirely dependent on the river -- wastes half the water it receives, according to an IndiaSpend analysis of water-use data.
The only Indian city that wastes water at a greater rate is Kolkata. And the situation in Bengaluru will only worsen.
Every Bangalorean -- 8.5 million people live in India's third-most populous city -- should get 150 litres of water per day. But what she gets is 65 litres, the equivalent of four flushes of a toilet. Water is supplied, on average, thrice a week.
Over the next nine years, the city's water demand is predicted to be three times more than supply.
Its population density 13 times higher than Karnataka's average, Bengaluru consumes 50 per cent of Cauvery water reserved for domestic use in Karnataka. As much as 49 per cent of this water supplied is what is called "non-revenue water" or "unaccounted for water" -- i.e., water lost in distribution -- according to the Bengaluru Water Supply and Sewerage Board (BWSSB) data.
"Inequitable supply to different parts of the city -- ranging from one-third to three times the average per capita daily supply -- makes this worse," Krishna Raj, associate professor at the Institute for Social and Economic Change (ISEC), Bengaluru, and author of a 2013 paper on the city's water supply system, told IndiaSpend.
Bengaluru's water loss is the second-highest among Indian metros: Kolkata leads at 50 per cent. The wastage figure for Mumbai is 18 per cent, New Delhi, 26 per cent and Chennai, 20 per cent. Across the world, cities lose only about 15 to 20 per cent of their supply, said the ISEC study, which pegged Bengaluru's losses at 48 per cent three years ago.
Former BWSSB chairman, T.M. Vijaybhaskar, admitted to a loss of about 46 per cent water at a conference in February 2016. "Of 1,400 MLD (million litres per day) of water pumped to the city, 600 MLD goes to waste," he said.
The ISEC paper attributed the wastage to two types of distributional losses: First, damages and leakages in the water supply system and, second, unauthorised water connections.
"Water leakages largely take place at distribution mains, service pipes and stand posts and together account for 88.5 per cent of water spillover, the rest being low leakages at main valve, meter joint stop valve, ferrule, air valve and others," the paper said. "This huge loss is directly attributed to the water seepage at various stages of supply."
Of the 270 thousand million cubic ft (TMC) of Cauvery water allotted to Karnataka by the Cauvery Water Disputes Tribunal, Raj estimated that, roughly, about 80 per cent is used for agriculture and industry (down from over 90 per cent in 2007). This leaves about 20 per cent for rural and urban domestic use, of which Bengaluru records the highest demand.
The city receives about 19 TMC of Cauvery water. Recently, the Karnataka State Urban Development Department provisionally raised supply by an additional 10 TMC to meet the needs of 110 villages added to the metropolitan area in 2007. A formal proposal to raise the city's water supply to 30 TMC from the Cauvery basin has been forwarded to the central government.
Sourced from a distance of 100 km, up to a height of 540 m, the BWSSB spends nearly 60 per cent of its budget in pumping water to the Bengaluru metropolitan region. With groundwater reserves overexploited and polluted, and its other two ageing reservoirs -- the 120-year-old Heseraghatta and 83-year-old Thippegondanahalli of Cauvery's Arkavathi tributary -- unreliable, Bengaluru is almost entirely dependent on the disputed river.
The large water losses, which ISEC has recorded for the last five years at least, offset any efforts to augment water supply through various stages of Cauvery river water supply projects. Thus, efforts to enhance per capita water availability to 150 litres per capita per day (LPCD) to meet World Health Organisation (WHO) and Central Public Health and Environmental Organisation (CPEEHO) standards remain unfulfilled.
"After Stage IV Phase II of the Cauvery Water Supply Scheme (CWSS) was commissioned recently, Bengaluru now receives 1,350 MLD of water daily," said Raj. "For the city's population of 8.5 million (Census 2011), this quantity officially raises per capita water availability to 158.82 litres, which is more than sufficient to meet the WHO and CPEEHO standards."
If unaddressed, the situation is only likely to worsen. In nine years, the city's demand (currently 1,575 MLD) is estimated to rise by 71 per cent, while the supply (currently 1,350 MLD) will rise only by a third, thereby tripling the demand-supply gap, according to the ISEC study of water demand and availability.
By 2031, Bengaluru's water supply will reach its optimum level (2,070 MLD) and stay there while the city's water demands rise further in the decades thereafter, widening the shortfall progressively, showed BWSSB data.
"Whenever the demand for water exceeds supply, urban water utilities quickly design water supply strategies, giving little importance to demand control or management. Failure of water supply authorities to incorporate demand-side factors in their policies leads to 'system-collapse' or 'institutional failure'," the 2013 paper said.
"As per the Cauvery Water Disputes Tribunal award, Karnataka receives lesser water per sq km -- 1 TMC of water is distributed over 134 sq km here, whereas in Tamil Nadu, it is supplied to 116 sq km," Raj said. "Add to this, there is inefficiency and inequity in Bengaluru's supply which must be addressed."