As used in ORS 543.650 to 543.685, unless the context requires otherwise:
(1) “District” means any one of the following:
(a) A domestic water supply district organized under ORS chapter 264.
(b) An irrigation district organized under ORS chapter 545.
(c) A drainage district organized under ORS chapter 547.
(d) A water improvement district organized under ORS chapter 552.
(e) A water control district organized under ORS chapter 553.
(2) “Principal Act” means the statutes, other than ORS 543.650 to 543.685, which describe the powers of a district, including, but not limited to, the statutes under which a district is proposed or is operating.
(3) “Water system” means any structure or facility constructed by persons and used by a district to achieve the district’s purpose under the district’s principal Act whether or not such structure or facility is owned by the district.