Water stress and the expenditure in zoning violated areas of Chennai: An empirical investigation

India as the largest user of groundwater in the world faces the risk of resources depletion and degradation. The study focuses on groundwater degradation and drinking water expenditure in 45 locations of 15 Zoning Violated Areas (ZVAs) in Chennai. We collected 45 groundwater samples in each pre- and post-monsoon seasons for testing heavy metals concentration levels and compared them with the World Health Organization (WHO)/the Bureau of Indian Standards (BIS) drinking water standards. We surveyed 797 households in the 14 ZVAs and statistically analysed drinking water expenditure. Scientific analysis reveals that Cadmium and Nickel are 15 and 7 times higher than the WHO/BIS standards in Nagalkeni of Pammal area. The analysis also shows that higher levels of concentrations of Lead, Nickel, Chromium and Cadmium in the groundwater in 25, 13, 3 and 1 locations respectively. Survey analysis indicates that 3,21,102 households have incurred an aggregate expenditure of $52.72 million per year on drinking water. The analysis shows that each of the economically weaker, lowermiddle and upper middle-income groups spend, on average, 11.64, 4.72 and 2.55 per cent of their daily income, respectively on drinking water. The study also informs that Pammal is the most vulnerable area in groundwater contamination and households in Ambattur area has incurred highest expenditure on drinking water. The regression analysis of the data reveals that variables, such as metro water, income and family size are statistically significant in explaining the water expenditure. The Computable General Equilibrium model for Chennai estimates shows that the increase in water resources , economic growth under the assumption that all the households will , economically weaker sections will not, contribute to investments for drinking water resources. The study proposes a household-right-to-know legislation, adequate metro water supply and an incentive-structured compatible land-use regulation to achieve sustainable use of groundwater resources.