We just uploaded a chapter from an old book published back in 1788, in London, called The Lady's Complete Guide, which is a big cookbook, but also has a great chapter on brewing beer. Here's a clip on the selection of the proper water:
Of Water proper for Brewing. To speak in general terms, the best water for brewing is river water; such as is soft, and has partook of the air and the sun; for this easily insinuates itself into the malt and extracts it virtues."
Please stop into The Reading Room and click on The Beer Historian - cheers.