Install a Pedestal Sink in Six Steps
Many people today want to update a bathroom, and one great way to do that is to install a pedestal sink in place of the old one. Here's the basics of how to install a pedestal sink thanks to DoItYourself.com:

Step 1: Prep the rough plumbing


Shut off the main water supply and empty the hot and cold lines into a bucket. At the sink location, place a bucket under the copper supply lines and, with a compact tubing cutter, cut them both off about 2 inches from the wall. Tighten the cutter slightly after each turn around the tube to prevent distortion of the soft copper.

Determine the distance from the center of the basin's drain to the wall. (On new sinks, this dimension is provided with the instructions.) Measure out from the wall and label this distance on the PVC waste pipe. Grip the P-trap, fitted with its elbow, alongside the pipe, with the trap's vertical end centered on the mark. Now mark the pipe where the PVC shoulder joins the elbow. Using a hacksaw, slice the waste pipe at this mark. To help guarantee a square cut, hold the saw parallel to the wall and do not apply downward pressure.

Step 2: Solder the supply lines


Carefully ream the inside edges of the copper supply lines with a pocketknife or the triangular blade on a tubing cutter. Doing this removes the burr left by the tubing cutter. Buff the ends of the supply lines with sandpaper until the copper is shiny. Coat generously with flux. Buff and flux the inside of the angle stops and slip them, with their escutcheons, over the supply lines. Light the propane torch and apply its bright blue inner flame to the stop, at the point where the supply line ends.

With your free hand, hold the tip of a length of lead-free solder against the copper tubing where it joins the stop, on the side opposite the flame. When the tip of the solder begins to melt, turn off the torch and run the solder around the joint. After it cools slightly, wipe with a damp cloth to smooth the exposed solder and remove any flux, which corrodes copper.

Step 3: Install a pop-up drain


Roll a wad of plumber's putty into a three-quarter-inch-wide sausage and wrap it around the pop-up drain, underneath its flange. Wipe the basin's drain hole clean and drop the pop-up drain into the drain. On the underside of the basin, push a gasket and washer onto the drain. Thread the nut onto the drain and tighten by hand. Using a wrench or water-pump pliers, complete tightening with a quarter-turn. Arrange the pedestal on the floor so it lines up with the PVC waste pipe and its center is about the same distance from the wall as the center of the basin's drain (see step 1).

Put the basin on the pedestal and against the wall. Adjust the pedestal placement and level the basin side-to-side.  Place a mark on the wall through each of the mounting holes at the back of the basin. This marking shows where to drill later for the lag screws that restrain the basin to the wall.

Step 4: Attach the trap


Holding the pedestal and basin together, move them away from the wall. Have an assistant hold the sink steady so it doesn't tip over. Test-fit the P-trap and elbow assembly to the PVC waste pipe, and gauge the distance from the floor to the top of the trap's open vertical end. Measure the same distance up from the floor on the tailpiece of the pop-up waste assembly.

Take off the elbow and place the P-trap's slip-nut and washer over the pop-up waste's tailpiece. Cover the P-trap's threads with plumber's tape or pipe dope and slide the trap up to the mark you just made on the tailpiece. Thread the nut on to the trap by hand. Tighten the nut with a wrench or water-pump pliers, taking care not to damage the chrome finish. Drill into the wall at the lag screw points marked in step 3.

Step 5: Mount the faucet, hook up the drain


Place O-rings (if provided) or rings of plumber's putty under the flanges of the faucet's valves and spout, and insert them into their appropriate holes on the basin deck. Slide a gasket and thread a nut underneath of each of the fittings. Tighten the nuts by hand, then finish tightening with a basin wrench. Gently move the sink back against the wall.  Arrange the mounting holes in the back of the basin to line up with the holes in the wall. Stick in the lag screws with their fender washers through the mounting holes and tighten with a socket wrench while checking for level.  Slide on the PVC waste pipe's cover and escutcheon, leaving the plastic visible.

Try fitting the elbow onto the waste pipe. If the elbow's slip nut threads onto the P-trap, go on to the next step. If not, there is still some room for adjustment vertically (by loosening the P-trap's nut on the pop-up tailpiece) and horizontally (by trimming the PVC waste pipe). When the elbow's nut threads easily onto the P-trap, mark where the end of the elbow comes in contact with the waste pipe. Prepare the mating PVC surfaces with PVC cleaner, then cover them with welding solvent. Keeping the elbow parallel to the P-trap's mouth, promptly slide the elbow onto the pipe as far as the mark. The weld sets, permanently, within three to five minutes.

Step 6: Make final connections


Put a washer between the elbow and trap, dope the threads, and tighten the nut by hand. Complete tightening with water-pump pliers. Measure the distance between one angle stop and its faucet valve, add an additional inch, and cut a chromed supply tube to the right length with a tubing cutter. Slide two compression nuts and a ferrule over the cut end. First, tighten one nut to the stop with a wrench, then bend (but don't kink) the supply tube a little # first to the side, then up # so its acorn head fits into the valve's outlet.

Secure the head to the valve with the second nut. Repeat the step with the other angle stop and faucet. With the lift rod in the up, or open, position, attach the pop-up stopper to the actuator arm, then fasten the arm to the lift rod with the screw provided. Slide the escutcheon and cover over the PVC waste pipe to conceal it.  Be sure the faucet valves are closed, then turn main water supply back on. Take off the spout's aerator and filter. Stand to one side and partly open one faucet valve. Let the water run for a moment to clear air and any debris. Do the same with the other valve. With the faucet turned off, check for leaks at all supply connections between the wall and the faucet's valves. Reconnect the aerator and filter.

Whew!  Now admire and enjoy your new pedestal sink for years to come!