I was in downtown SF and also had the same experience in San Mateo. The water dispensed at the airport is also pretty vile, after a transatlantic flight when the chlorine had time to disperse it actually smells like swamp water.
I don't know then...everyone I've ever discussed it with has praised SF water. I'm really sensitive to the taste & smell of chlorine and minerals too. I don't know what could be responsible for the difference that you experienced.
