What should i buy to purify my water?

[sphelps]

Your needs will depend on the quality of your tap water. Here in Stoon I get a TDS of about 180ppm from the tap so I use a full 6 stage RO/DI to bring this down to the range of 0-4ppm. I've talked a few people down in BC who get a reading as low as 20-30ppm so they can usually just use a dual or triple stage (no ro or di) and get similar results as me.

RO units are very wasteful and I don't believe you should use one unless you need to.