327D.86  When rates effective.
  All such rates not so suspended shall, on the expiration of thirty days from the time of filing the same with the department or of such less time as the said department may grant, go into effect and be the established and effective rates, subject to the power of the department after a hearing had upon its own motion or upon complaint, as herein provided, to alter or modify the same.
[C24, 27, 31, 35, 39, §8103; C46, 50, 54, 58, 62, 66, 71, 73, 75, §479.69; C77, 79, 81, §327D.86; 81 Acts, ch 22, §22]