Water being acidic is one of the major reasons for the rusting/corrosion of the GI pipe. GI is no longer the most suitable material for water. Plastics like PVS/HDPE/PP are the current materials for pipes. They are inert and do not corrode or rust. It is advisable to change from GI or mild steel, if it is also used, to one of these plastics.
Contributor: S S Ranganathan (https://www.indiawaterportal.org/users/ssranganathan)