Upon the filing of a petition the court shall immediately fix a time for hearing it which shall be at the earliest convenient date. At such hearing the court shall hear the matter de novo and may take such testimony as it deems necessary. Its proceedings shall be summary and informal and its determination as to whether an emergency such as is contemplated within the meaning and purpose of this chapter exists or not and whether the expenditure authorized by said order is excessive or not shall be final.
RCW 36.40.170