Fire hydrants of the standard of those now maintained by the City or other fire hydrants of equal efficiency shall be maintained by the City along its main pipelines at the monthly rental for each hydrant of $1.00. Fire hydrants are to be used when directed by the Fire Chief or his assistant, for the purpose of flushing lines by the city crew, or for other uses with specific authorization by the City Superintendent. Anyone using, misusing, or operating a city-maintained fire hydrant for any other reason shall be guilty of a gross misdemeanor and punishable by a fine of $500.00 for each offense.