I would think you would want the brewing water report, although it's probably worth getting a report on each, that way you know your starting point AND how well your filtration works.
If your filter ever craps out you'll also know if/how you need to treat the tap water.
Something is always fermenting
...."It's Bahl Hornin'"Primary:Brite Tank/Lagering:
Tart Cherry Cider, Belgian Tripel, AHA Summer Ale, Sonoma County Organic Cider, Maibock Bock, Ommegang Abbey Ale Clone, Belgian Golden Strong, Belgian Quad (Grand Reserve), Belgian Pale Ale, German Pils (split WLP830 & WLP838)Bottled:
Contentment (Trappist), Derangement (Belgian Dark Strong), Kranky (Kolsch v1.1), Wise One (Wit)On Deck:My Site: www.restlesscellars.com