>>13784 I don't think I would have a water filter one - they tend to just need cartridges or salt refills or the time, and that's a bit of a hassle. Our house came with a "water softener" and we're always having to buy the salt blocks - not convinced by it.
I would have one of these boiling water taps though, they seem a lot more useful (and economical); instant tea at any time without having to fill/wait for a kettle.
>>13784 Depends on what you want to take out and what your tapwater is like to begin with.
A combined carbon and particulate filter can improve the taste, it can take out some nitrates and nitrites which get into tap water as agricultural run-offs into groundwater. They take chlorine out of the water which is meant to be better for your health (but can't take out chloramine as easily, and water companies are highly secretive about what they add in to water so it's hard to find out if you have chlorine or chloramine.)
The other problem with carbon filters is that it's essentially impossible to tell when they're used up, and if you use them for too long they can actually start leeching more chemicals back out into the water.
Water softeners are useful if you live in a hard water area and your kettle scales up very quickly, but it you use soft water for drinking you should think about calcium + magnesium supplements to replace what you would have if you were drinking hard water.
If you're not sure just get a Britta filter and use that for a while.
The disadvantage for most that they do very little meaningful effect for their money. Anything it is removing was quite harmless and nominal anyway. Unless you are in a hard water area and you have a softener fitted (which is best done further back to protect things like the boiler washing machine ect) but then you wouldn't need a different tap.
Unless of course you are going down the path of sticking a full reverse osmosis unit under your sink. Which is a much more expensive bit of kit but would remove nearly all dissolved material in the water, and put it at a level of purity that you could theoretically wash things to spotless in it without any detergent because of its abrasive properties by letting it just soak in it. (It is what they use for those window cleaning pole systems). It is safe to drink but I can't say I've ever seen much point in the difference.
A meth cook who is seriously invested in the absolute purity of his product no less. With most cooks you're lucky if they bother scraping the coating off the pseudoephedrine tablets never mind worrying about finding even distilled water for their various solvent solutions.
