I know this doesn't directly answer the OP's question but two years ago in the States I bought a PUR filter that snaps on to the faucet and a box of replacement filters (they last about three month each). That came out to be less than Us $75 ($25 for the unit and $48 for 6 additional filters) for clean water for almost two years ( a LOT less than we were spending buying bottled water every week!). We have been very pleased with the performance of the system as well as its ease of installation.