This ca. 1890 structure was the spring house for the Clarendon House Hotel. Details can be found at the attached link to the 1976 historical survey of Clarendon. This structure is the map #10 entry.
The cover photo is from 2006 town records. The photo at the bottom was taken by Rick Bersaw in 2017.
Photos from the 1976 Clarendon History book are below. The first one is from 1910.
A YouTube featuring the Spring House can be found here. It was made by Phil Mandolare in 2019.