Wash. Rev. Code § 87.03.705
The jury, or the court if jury be waived, shall first determine whether the lower drainage system or systems when so improved will afford a sufficient drainage and outlet for both the drainage district and irrigation district, and if it finds that it will not, the finding shall terminate the proceedings so far as the connecting with the lower drainage district or districts is concerned and the costs shall be paid as in other suits: PROVIDED, That the irrigation district may maintain said suit for the purpose of acquiring the necessary rights-of-way from the lower drainage district or districts and the landowners in said lower district or districts that will not interfere with the operation and maintenance of the drainage system in the lower district or districts.
RCW 87.03.705