chennai what if you could drink water coming out of your air conditioner every day residents of an apartment complex in velachery have done just that storing ac unit water in sumps and using it after testing it for potability in a private laboratory at guindy r viswanathan who came up with the idea researched online and found the water could be used for drinking he decided to send it for tests even if unpotable i thought why lose the water said the former deputy director of taramanibased central electrochemical research institute some of the objections including that water could be contaminated with lead were proven incorrect by the report the report from chennai mettex lab pvt limited stated that the sample of ac unit water was within the acceptable limits of drinking water specification as per is 105002012 with respect to colour odour turbidity total dissolved solids hardness alkalinity sulphate iron nitrate fluoride e coli and coliform viswanathan saideach of the 40 ac units in his complex viswanathan said worked for at least eight hours a day and led to collection of 23 litres of water an hour 960 litres a day and 345 lakh litres a year b j pandian who retired from water technology department of tamil nadu agriculture university said ac water could definitely be reused however whether it is potable for drinking should be checkedtamil nadu pollution control board engineers told toi they had not received any such sample and requested residents to get it checked with tamil nadu water supply and drainage board and metrowater before consuming them