Ron,
The water source is discussed in the book
Candelariaand Its Neighbors: Columbus, Metallic City, Belleville, Marietta, Sodaville and Coaldale by Hugh A. Shamberger. This is one of a series of self-published books on Nevada mining camps -- it was published back in 1978.
When the Northern Belle Mill and Mining began constructing its 20 stamp mill in 1873-4 it found water about six miles northeast of Belleville. This was on the southern slope of Excelsior Mountains. This spring was called Belleville Spring and was at 6,400 feet elevation (compared with 5,160 feet for the mill). A pipeline of 6-3/4 miles of wrought-iron pipe was installed.
A few years ago Dave Peterson, George Sapp and I scouted out the location the photographer used to take the view from above the upper mill. We continued up the slope and found the remnants of a reservoir.
This woould have been the supply for Belleville while the mills operated. Later after the mills and town went away the railroad hauled in water for its water tank and the depot from Basalt.
Basalt did not have water; but, the railroad accessed the pipeline built from the White Mountains to Candelaria to fill its water tank and the various tank cars used to move water down the grade to Belleville. At Belleville the railroad had a siding on the hillside above the elevation of its water water tank and a pipeline connected the two.
Brian Norden