Mmkay, so there's next to zero actual sulfur (sulfide) in Philly's water, so it's vanishingly unlikely that it's coming from the City's side. What can happen, however, is that your property has bacteria reproducing in the pipes or--more often--in the hot water heater. Some types of bacteria can convert the sulfate that's naturally in Philly's water into sulfide, which would give you a "fart" or "rotten egg" smell.

Another possibility is that you have a cross connection situation, where some genius accidentally connected a sewage pipe to a drinking water pipe. If you're not projectile vomiting a few hours after drinking your water, and if you don't have to strap yourself down on the toilet because you've turned into a diarrheal rocket, that's probably not your situation.

A third possibility is that the smell isn't coming from the water out of the tap, but from the drain. If your trap is dry, or if you have no trap, that's a distinct possibility.

Yours truly, a "Philly water nerd".