Toronto Water Profile for Homebrew Beer

Modifying your water profile is one of the last hurdles for an advanced homebrewer.  Changing your water will not make a bad beer good.  It will make a great beer...fantastic.

Your city's water profile will affect your final beer.  You can manipulate how a beer is perceived by fine tuning your water's mineral profile.  For example: higher calcium and sulfate levels can make your hops and bitterness brighter and less will lend itself to a maltier beer.

To help me figure out the amount by weight of my water additions I use EZWaterCalculator.  There's also the popular Bru'n Water (more powerful but has a big learning curve).  Having tried both, I've found the numbers come out very close. 
 

Link: Toronto Water Quality Website