Go for H2O!
A good water filter is the best and maybe the only solution nowadays.
Just make sure the filter you choose removes the most spectrum of contaminants. Usually a professional filtration system worth investing in is a 5 to 7 stage water purifier system. Each stage will remove certain types of contaminants, and all stages combined should protect you from just about every contaminant. A reverse osmosis water filter with activated carbon pre-filters are what we believe to be the most thorough and cost effective way to purify drinking water.