Have leak at joint where the city water comes into the house. Will silicone caulk work?

No on the caulk. That would patch the outside of the leak and it will not hold, especially since the surface is wet. Could you describe the fitting at or on the meter since I'm guesssing this is the site of the problem, right?

Please be more specific, Describe the fitting and the point it's leaking from. Thank you, Tom