Click and hold the "Rectangular Marquee" button to reveal the selection menu. Select the "Elliptical Marquee" tool, then click and drag to form the area where the ripple will appear. Rounder ellipse selections will result in ripples as viewed from above, while flatter ellipses simulate ripples from a distance.
Press Ctrl+J (on Windows) or Command+J (on Mac) twice, depending on which system you use. This creates two new copied layers of the ellipse section(s). Click the icon shaped like an eyeball next to the top ripple layer to hide it.
Select the bottom ripple copy layer, then hold Ctrl (on Windows) or Command (on Mac) and click on the layer's preview thumbnail in the "Layers" pane. This re-selects the ripple area.
Click the "Filter" menu in the top menu bar, then hover over the "Distort" submenu. Select "ZigZag" in the second submenu that appears.
Choose each option in the "Style" menu to see which looks best with the shape and size of the ripples in your photo. The categories "Around Center," "Out from Center" and "Pond Ripples" all create slightly different effects and fit each photo differently.
Set the "Amount" slider bar between 60 and 70, and the "Ridges" between 10 and 12. Press Ctrl (or Command)+D to deselect the ripple. Click on the top ripple layer, then press the eyeball icon to make it visible again.
Reselect the "Filter" menu, then "Distort," then "Zigzag." Set the "Style" at "Out from Center," then set the "Amount" to 100 and the "Ridges" to 4 or 5. Click OK.
Press Ctrl (or Command)+D to deselect the ripple layer. Click and hold the Ellipse Marquee tool in the menu, then select the Rectangular Marquee. Click and drag the selection rectangle until it covers the middle 50 percent of the ripple.
Press Shift+Ctrl (or Command)+ I to invert the selection, then press Ctrl (or Command)+ D to delete the outside of the ripple. Your ripple should appear to have wide waves in the middle, and thin waves on the outside.
Click "Layer" on the top menu, then select "Merge Down" to merge the two ripple layers into one. Double click the layer's label to rename, if desired.