I know this might be bigger than what you are looking for, but if you are particular about the water you drink also, my family purchased a Reverse Osmosis filter for our tap. It's great! I love it and use it with my bettas.
One thing about reverse osmosis...it is great because it really does remove everything out of the water, but its not so great because it removes EVERYTHING out of the water. The water is completely stripped of any minerals that are beneficial. But! If you want just water, Reverse Osmosis is a good way to go.