Once installed, towel bars look like they are glued to the wall, but that's seldom the case. Almost all are connected to brackets that are screwed to wall studs or to anchors set into the wall. When you install these brackets, you have to drill holes for the screws or screw anchors, and in most cases, that's not very challenging. In fact, you might find that the most difficult part of the installation procedure is getting the towel rack level.
Look for a Stud
If you're installing your towel rack on drywall, it will be more secure if you can attach at least one of the mounting brackets to a stud. While you can locate studs by tapping on the wall and listening for a dull sound, it's more accurate to use a stud finder. If none of the studs are in the right places, don't worry; you can mount the brackets with screw anchors. Don't bother searching for studs if you're mounting the towel rack on tile -- screw anchors hold much more securely to tile than they do to drywall.
Mark the position of one of the towel rack holders on the wall, using a pencil. You can put the rack anywhere you like, but if you want to align it with other features in the bathroom, use a tape measure to measure its distance from the floor and to center it on the wall.
Unpack the towel rack, and assemble the rod and the holders on either end. Set the rack against the wall with one of the holders centered on the mark and put a level on the rod. Adjust the holder on the other end to make the rod level, then draw outlines of both holders on the wall, using a pencil.
Remove the mounting bracket from inside of one of the holders and put it against the wall inside the outline you drew. Check the bracket to make sure the proper end is facing up, and then mark the positions of the screw holes. Repeat with the other bracket.
If you're installing the rack on tile, lay masking tape on the wall and redraw the outlines of the holder; mark the positions of the screw holes on the tape. The tape prevents the drill bit from wandering when you drill the holes for the screw anchors.
Drill a hole on each mark with an appropriate bit. If you're using wall anchors, the diameter of the bit should be the same as that of the anchor to ensure a tight fit. A 1/4- or 3/8-inch bit usually works. If you're drilling through tile, use a masonry bit.
When drilling through tile, run the drill at half speed and immerse the bit in water frequently to prevent it from overheating.
Position a mounting bracket over each set of holes, and drive a screw through each hole and into one of the anchors with a Phillips screwdriver. Make sure the brackets are tight -- if one bracket is loose, the towel rack will wobble.
Assemble the towel rack and place the holders over the brackets. Tighten the set screw on the underside of each bracket with a flat-head screwdriver or a hex wrench.