milk type jugs degrade. old 2 liters are better.
tap water is just fine. water does not go bad.
I got my Berkey water system from Farris and I get my replacement filters from them also. Small shop and Bob will talk your ear off if you have the time, but I shop there as much as I can to support a local business. IMHO Berkeys are the only way to go for water filtration.
If water went bad, life on this planet would not exist.
"There are no finger prints under water."
then maybe water went good?