Swimming Pool Water Blue

What Makes Swimming Pool Water Blue?

Contrary to popular assumption, water does not get its blue color from the sky. Any water, including swimming pool water, will always be blue because of the nature of both light and water, and how the two interact.

Sky Blue

DEEP BLUE

Water molecules absorb the colors on the red end of the light spectrum quickly, but the blue end of the spectrum travels further through water before being absorbed. Clean water always appears blue, and deeper water appears more deeply blue as more of the other colors of the spectrum are absorbed.