Water filtration does not lower your footprint.
What comes out of the filter is approx 1/3 the water that went in, so it actually increases your water consumption substantially.
IMO however, we cannot rely on our municipalites to provide clean water, whether that be defined as chemical or pathogen free, so in my mind it's justifiable.
The Silicon Valley, where I live, has the highest rate of pet cancer in the country. I've lost two cats to cancer in the last few years, and neither was old.
Pure water has no taste. What you're tasting is dissolved solids. The only question is, which ones?