Basically been covered above but yeah we got a seperate "drinking water" tap installed by the plumber when he put the softener in. There is the slightly higher sodium content issue if you have small children although for adults apparently the amounts we are talking its not a massive issue. The main other aspect is the taste, I don't mind either way as I am originally from Scotland and used to very soft water but the missus literally can't drink the stuff so we needed a hard water tap for that alone. We use the hard water for general drinking but soft water in the kettle for teas & coffees which means you avoid those bits of scale you used to get floating in your coffee. Also means the mugs don't stain as easy for some reason. I'd definitely get a seperate hard water tap instead of just keeping your main kitchen tap on the hard supply though. If you do that every time you want to wash something up you will end up with the same old limescale marks, also on the draining rack etc. As another note, if you have an outside tap that should be on the hard supply for plant watering etc, plants don't like soft water apparently.