Sec. 561.13. Records for each plant and for territorial subdivisions

(a) Unless otherwise authorized or directed by the commission, each city, borough, village, or town and each water plant shall constitute a cost area and separate records shall be maintained of the book cost of water plant located therein. The term “plant” as here used means each source of supply, each pumping station (small booster stations may be grouped), each water treatment plant and the transmission and distribution system in each city, borough, village, town or such other operating area as the commission may require.

(b) Operating revenues shall be recorded so that the amount for each city, borough, village, town or other operating area required by the commission, may be readily determined.

(c) Records shall be currently maintained so that the utility will be prepared to show operating revenue deductions separately for each city, borough, village, town, or other operating area required by the commission, and for each water plant; provided that, with the approval of the commission two or more such territories which are contiguous and are operated as a unit, may be combined into an accounting division.

(d) Records shall be kept to show separately the accumulated provisions for depreciation applicable to property in each accounting division.