Originally constructed in the 1920s, the Neptune Pool was designed and enlarged twice by William Randolph Hearst and the architect Julia Morgan into the pool that is seen on tour today. The Neptune Pool, built above ground, is line with marble and serpentine tiles. The ensemble consists of modern and ancient Roman architectural elements, Baroque and Art Deco sculptures, and decorative marble handrails. The Neptune Pool was drained for renovation and repair of the plumbing and concrete shell as well as conservation of the Art Deco sculptures. The photo below shows what the Neptune Pool looked like during a restoration project which was completed in 2008. Additional restoration on the Neptune Pool is currently in progress.
The Neptune Pool as it appears under the current restoration project.
The final version of the pool as it stands at the Castle today is 104 feet long, 58 feet wide and 95 feet wide at the alcove. It is 3.5 feet deep at the west end, 10 feet at the drains, and holds 345,000 gallons of water. Other notable aspects of the Neptune Pool include the oil-burning heating system, the Vermont marble that lines the basin, gutters, and alcove, and four Italian relief sculptures on the sides of the colonnades.