Before you begin, gather all necessary tools and supplies. Close the bathtub drain stopper to prevent any screws or small parts from falling down the drain. Lay a thick rag or old towel in the bottom of the tub beneath the spout to protect the surface from scratches from dropped tools. This initial setup prevents costly mistakes and makes the job go smoothly.

To determine the correct removal procedure, you must first identify your spout type. Get down low and look closely at the underside of the spout, right where it meets the wall. If you see a small hole, you likely have a slip-on spout which is secured by a set screw inside that hole. You may need a flashlight to see it clearly. If there is absolutely no hole or screw on the top, bottom, or sides of the spout base, you have a thread-on (or screw-on) spout.

For a SLIP-ON spout, insert the correct tool (usually an Allen wrench or a small screwdriver) into the set screw hole you located. Turn the screw counter-clockwise a few turns to loosen it. You do not need to remove the screw completely. Once loose, firmly grip the spout and pull it straight off the copper pipe. It may require some wiggling and twisting. For a THREAD-ON spout, grip the entire spout with both hands and turn it counter-clockwise. If it's too tight, insert the handles of a pair of pliers or a screwdriver into the spout opening for leverage. For very stubborn spouts, wrap a rag around it, grip it with a pipe wrench, and turn counter-clockwise. The rag protects the spout's finish in case you need to return it.

With the old spout removed, you will see the pipe stub-out. Use a putty knife and a rag to meticulously clean any old plumber's putty, caulk, mineral deposits, or sealant from both the wall surface around the pipe and the pipe itself. For a thread-on installation, pay special attention to cleaning the pipe threads. A clean surface is essential for the new spout to seal correctly against the wall and prevent leaks.

Now, install the new spout. For a THREAD-ON spout, wrap the pipe's threads with 2-3 layers of Teflon tape in a clockwise direction (so it doesn't unravel as you tighten). Then, screw the new spout on by hand until it is snug and facing down. If it's not tight when facing down, give it another full turn. For a SLIP-ON spout, check if your new spout comes with a plastic adapter. If so, slide it onto the copper pipe first. Then, slide the new spout over the pipe until it sits flush against the wall. Ensure the set screw hole is facing down. Use your Allen wrench or screwdriver to tighten the set screw until it is snug. Do not overtighten, as this can dent the copper pipe.

To create a final waterproof barrier, apply a thin, neat bead of plumber's putty or tub & tile silicone caulk around the base of the spout where it meets the wall. This prevents water from splashing behind the spout and into the wall cavity. Once sealed, turn on the water and observe the spout. Check for leaks around the base. Pull the diverter to send water to the showerhead. Check that the diverter works correctly and that water is not leaking excessively from the spout. A small drip from the spout while the shower is on can be normal, but a steady stream indicates a faulty diverter inside the new spout.