Service tax

 Services provided to the Government or local authority by way of erection, construction, maintenance, repair, alteration, renovation or restoration of - pipeline, conduit or plant for (i) drinking water supply (ii) water treatment  (iii)sewerage treatment or disposal;then exempts from taxable services  from the whole of the service tax leviable thereon under section 66 B of the said Finance Act,

otherwise not

Water is an article and cannot be subjected to ST. If at all in future itmaybe included in VAT/ CST. In fact the Tribunal has examined this in case of apartment owners and observed that electricty and water are goods not liable for ST.