CLSA-backed Earth Water Group, a specialised water treatment company, is planning to raise Rs 6.5 billion-Rs 8.5 billion through an IPO. The company is expected to file the draft red herring prospectus soon. Promoters may dilute a 15-20 per cent stake through the proposed share sale although the terms and conditions are yet to be finalised. The Earth Water Group has appointed domestic investment bankers IIFL and ICICI Securities for the IPO, while AZB & Partners and J. Sagar Associates are the legal advisers. This will be probably the first such IPO in the water treatment segment since VA Tech Wabag’s debut on the exchanges in 2010-11.