Presumably you’re doing this for a larf.
The problem stems from using a conversion rate based on a planet which is 70% covered by water, in the wealthiest country, which has ample supplies of fresh water, and where water supply is treated as a service and not a ‘product’.
Slightly more accurate comparisons would be obtained by pricing water delivered to the middle of the Australian outback, or the center of the Sahara. Or the cost of setting up a desalination plant on a small island with a smallish population and amortizing out the cost of the potable water it produces over 20 years.
Fairly more accurate would be the cost of a unit of water on the moon, or more likely, on an asteroid in the belt.
Your base comparison doesn’t involve water that was purified and bottled on an extraterrestrial planet, lifted into orbit, flown across 10 systems by a freighter, and sold in a space station - fighting off pirates every step of the way!.