Thanks for all the replys. In South Africa (at least in my location) water borne diseases aren't really a problem. But, i suppose that the problemsthat one expeiences are the ones that aren't anticipated.

The only water purification pills that I can get hold of are chlorine pills packaged in strips ('cards'), so a useful number of pills is rather bulky. But I think that they are worth the space.

Thanks for the advice.