The Tenino Stone Company closed in 1918[2] and when quarry operations ended in the 1920s, the formation filled with spring water.

There are two proposed causes to the cavities filling with water - that workers in the quarry opened up a natural spring or that personnel turned the pumps off as they left the job in a labor protest.

[3] The area was closed and was deemed a no-trespassing zone, but the quarry became an unofficial pool in the community.

[5][6] Further renovations were undertaken into 2024 which included additional safety measures and access for disabled people; a large reopening of the facility was in June 2024 as part of the city's Tenino Family Fun Day event.

The large pool, used for swimming and diving is measured up to 80 feet (24.4 m) in depth and is deep enough to be considered an inland lake.