Colorado Div. of Water Resources records (Dam ID = 060225) indicate that the lake was built by Adolf Waneka in 1865 to hold water coming out of a nearby spring. This was corroborated by Clancy Waneka, who in 1989 told the Lafayette News that "Sometime in the 1860s (Adolf Waneka) scooped out a small reservoir that held about 13-acre-feet and this was recorded and is a matter of record in the State Engineer's office." Adolf gave his interest in the lake to his son, Henry “Boye” Waneka, who then sold to William, Frank and Guy Harmon in 1897. Northern Colorado Power Company documents from 1906 and reservoir records at the Colorado Div. of Water Resources both show that the original name of Waneka Lake was “Henry Waneka No. 1 Reservoir.” Northern Power expanded the lake, which was later called Plant Lake, in 1906 to store 28 million cu. ft. ( m3) of water for its steam generators. Mary Miller and the power company split 50/50 the rights to the additional water stored. When town founder Mary Miller owned the lake, it was known as the Millar and Harmon Reservoir.