A friend in San Diego bought a home 15 years ago with a view of Torrey Pines State Beach for about $1.9M (whitewater and top notch sunsets). The same exact model with no ocean view, built at the same time, in the same subdivision with a similar size lot, sold for about $950K.
I think this ratio of about 2:1 is common when the water view is high quality. If the property is literally waterfront, not just water view, I'd add another 50% to the listing price. Space along the water is much more limited than space that can merely see the water.
In terms of a CMA, you'd find an extremely similar home in the same neighborhood/area, not located on the water and the adjustment in sales price would be reflective of the waterfront value.