ORS § 224.020
Whenever the council of any city deems it necessary or expedient to construct a sewer partially within and partially without the city, or to construct a sewer outlet, or do any other work, acts or things without the city for proper disposal of sewerage and drainage, the city, through its council, may acquire by purchase, condemnation or otherwise, any property rights of way, easement and other rights without the city as may be needed or deemed essential for the construction of the sewer, sewer outlet, or other works. It may also provide for and do all things which may be necessary or deemed essential for proper construction of such sewer, sewer outlet, and for other works, acts and things which may be deemed necessary or essential for the proper disposal of sewerage and drainage from the city and adjacent territory.
ORS 224.020