The picture was taken at a garden shop in the touristy area of San Clemente. Of course. Because if you say "San Clemente" there are only two reactions possible: Baby Boomers will remember the Western White House of Richard Nixon (which is for sale, btw) (for $63 million, since you know you wanted to ask) or they'll know the town as a major surfing destination.
The sign at the base says "Sustainable Functional Art WillandJane.com" This shower is just one example of their work, so if you're interested, go to the website.
At the WillandJane site, you'll see a charming picture of some children enjoying a working shower/mosaic/surfboard like this. Their Gallery page shows other designs, using recycled surfboards, starfish and shells, and glass mosaic pieces.