The idea of using water from Naples for pizza dough is not a new one. That is what Naples 45 in NYC did at one time. Later it commissioned someone to replicate the chemical composition of water from Naples rather than importing it. I don't know if Naples 45 is still doing that or whether it has switched to municipal NYC water.
Technically, it is possible for the water to affect the dough and the finished product. The two main factors are degree of hardness (hard or soft) and the pH. Chlorine is also a factor. There are ways chemically for adjusting for hardness and pH, and for chlorine you can just leave a container of water out in the open overnight to allow most of the chlorine to dissipate. Not too long ago, when I was making some DiFara clone doughs, I decided to use my local city water, just as Dom DeMarco does in using NYC water in making his doughs. Not knowing what was in my water, I went online and looked at the cityís most recent water quality report. From that report, I saw that the hardness numbers were within the acceptable ranges but the pH was higher than the optimum (it was around 7.6). I could have used some chemical to correct the pH but instead I simply followed Tom Lehmannís recommendation and increased the amount of yeast by a small amount. I canít say that I could tell a big difference since I rarely use tap water in making my doughs. I have tried just about all forms of water at one time or another, including imported carbonated water, and havenít been able to tell a difference in the results. Theoretically, any water should work if it is potable (drinkable).
You might find this King Arthur mini-tutorial on water of interest, including the reference to the effects of chlorine on starters: http://web.archive.org/web/20051027064252/http://www.kingarthurflour.com/stuff/contentmgr/files/4a1eb4311b0be08b2b590b39ac3f2c77/download/KAF-04-009+Water.pdf.
Not too long ago, just out of curiosity, I decided to take a look at the numbers for NY Cityís water. As with just about all water quality reports these days, the NYC water quality report is available online. For those who are interested, it can be downloaded at http://www.nyc.gov/html/dep/html/drinking_water/wsstate.shtml.
For more information on Naples water, you can also read the exchanges that pizzanapoletana (Marco) and I had on that topic, starting at Reply 34 at http://www.pizzamaking.com/forum/index.php/topic,1378.msg13898.html#msg13898.
EDIT (3/15/13): For a replacement article by King Arthur on water, see http://www.kingarthurflour.com/professional/water.html