Here's another question and answer with Desert Tile & Grout Care. The question today is, "How can I tell if my grout has been properly sealed, or if it is time for new sealing?"
The answer is, put a few drops of water in the grout joint. If the grout joint has been sealed, the water will bead on the surface. If it soaks into the grout, it requires sealing.
Desert Tile and Grout Care
2917 E. Park Avenue
Gilbert, Arizona 85234
Office: 480-288-4475
Website: http://www.deserttileandgrout.com