That sounds more like, Coopers always seem to be a cut above the rest. Old Family Brewery, they had their own water well when they were at Eastern Suburb Leabrook.
No idea where they source from now, maybe spring water (AKA Bore [bighmmm]) by Tanker or even D-Sal from a new Bore.
Brewery Water - Coopers - OsmofloQuote:
All water used by Coopers originates from aquifers beneath the brewery, reducing the demand on Adelaide's reticulated water supply. This underground water is clean but saline and is purified by reverse osmosis.

