You would have transformer losses at 575 that you don't have at 208. On the other hand, I have heard that some electric companies adjust the rate to account for transformer losses if you take a higher-voltage feed.
On the other, other hand (I have lots of hands), the I^2R losses for distribution will be lower at 575.
However, in the final analysis, the choice of voltage isn't going to have any effect at all on your water bill.
[This message has been edited by SolarPowered (edited 04-06-2005).]