Bob: I used to work for the water dept. Have them come out and disconnect the line at your side on the meter. See if they have the recommended amount of pressure. If not, maybe the line from the meter to the main needs reamed out. This should be a freebie. Otherwise it could be galvanized pipe clogging with age. Be sure you do not have a galvanized line connected to a copper line. This creates a problem in time also. Seen a lot of strange things in a situation like yours...