The cases in this jurisdiction have so treated it and so do we.See, e.g., State ex rel. Pac. Power Light Co. v. Department of Pub. Works, 143 Wn. 67, 82, 254 P. 839 (1927); State ex rel. Spokane v. Kuykendall, 119 Wn. 107, 116, 205 P. 3 (1922); State ex rel. Pac. Tel. Tel. Co. v. Department of Pub. Serv., 19 Wn.2d 200, 232, 142 P.2d 498 (1943). See also Attorney Gen. v. Department of Pub. Utils., 390 Mass. 208, 455 N.E.2d 414, 424-25 (1983); Cohen v. Pennsylvania Pub. Util. Comm'n, 90 Pa. Commw. 98, 494 A.2d 58, 62-63 (1985).
Neither the cases cited nor those we have found decide the precise questions raised by the appellants. The necessity of taking into consideration property used by a utility in the performance of its service wheresoever situated in order to fix a rate base was pointed out in State ex rel. Pacific Power Light Co. v. Department of Public Works, 143 Wn. 67, 254 P. 839, P.U.R. 1927C, 781. In that case, the value of a part of the property of the utility in the state of Oregon and of property in Washington were taken together in making up the rate base, and in affirming this procedure we said:
We have many cases holding that classification of property made in such proceedings will be upheld. Northern Pacific R. Co. v. King County, 93 Wn. 89, 160 P. 8; State ex rel. Pacific Power Light Co. v. Department of Public Works, 143 Wn. 67, 254 P. 839. But this is not a valuation proceeding.
" [6] Finally, it is contended by the appellant that the judgment should be reversed because the trial court made no findings of fact. As above stated, this was primarily a rate-making proceeding and, as such, came under Rem. Comp. Stat., § 10428, State ex rel. Pacific Power Light Co. v. Department of Public Works, 143 Wn. 67, 254 P. 839. Section 10428 provides, among other things, that, upon a hearing before the court to review an order of the department, the "court shall enter judgment either affirming or setting aside the order of the commission under review."