Begin by shutting off the water supply to the toilet. The shutoff valve, also known as an angle stop, is typically located on the wall or floor behind the toilet. Turn the handle clockwise until it is fully closed. Next, flush the toilet and hold the handle down to drain as much water as possible from the tank and bowl. Use a sponge or a wet/dry vacuum to remove any remaining water from both the tank and the bowl to prevent spills during toilet removal.

With the water off, use an adjustable wrench to disconnect the water supply line from the fill valve on the underside of the toilet tank. Have a small towel ready for any drips. Next, pry off the plastic caps covering the closet bolts at the base of the toilet. Use the adjustable wrench or a socket set to remove the nuts from the closet bolts. The toilet is now free from the floor. Straddle the bowl, get a firm grip, and gently rock it side-to-side to break the wax seal underneath. Lift the toilet straight up and move it to a pre-prepared area, such as on old towels or cardboard, to avoid scratching the floor or making a mess.

Once the toilet is gone, you will see the old wax ring and the toilet flange. The first priority is to plug the drain pipe with a large rag or old towel. This will block sewer gases and prevent anything from falling in. Next, put on disposable gloves and use a putty knife to scrape all the old wax off the flange and the surrounding floor. Clean the area thoroughly so you can clearly see the flange, the fasteners holding it to the floor, and its connection to the drain pipe. Identify whether the flange is PVC (usually white or black), ABS (black), or cast iron (dull, dark gray metal).

Locate the screws that secure the flange to the subfloor. Using a drill with a driver bit or a screwdriver, attempt to remove these screws. If the screws are old and rusted, they may strip or break. If a screw head strips, you may need to use a screw extractor bit. If the screws are completely seized, a good option is to use an oscillating multi-tool or a reciprocating saw with a metal-cutting blade to carefully cut the screws flush with the floor, between the flange and the subfloor. Once all fasteners are removed, the flange should be loose from the floor but still attached to the drain pipe.

A PVC or ABS flange is solvent-welded (glued) to the drain pipe, so it must be cut out. The safest and most professional method is to use a special drill bit called an inside pipe cutter or flange cutter. Attach the bit to your drill. Carefully lower the cutter into the flange until the cutting edge is positioned just below the bottom of the flange hub, inside the drain pipe. Ensure it is level. Start the drill slowly and apply steady, even pressure, allowing the cutter to slice through the pipe from the inside out. Once the cut is complete, the flange will be free from the drain pipe and can be lifted away. Be extremely careful not to cut too low, as this will shorten the drain pipe and complicate the new installation.

Removing a cast iron flange is a significantly more demanding task. Ensure you are wearing heavy-duty gloves and safety glasses. These flanges are often sealed into a larger pipe hub with lead and oakum, or they are part of the pipe itself. The most common removal method is to carefully break it. Place the tip of a cold chisel on the top ring of the flange, away from the central hub. Strike the end of the chisel firmly with a small sledgehammer or heavy machinist's hammer. Reposition the chisel and strike again, working your way around the ring until it cracks and breaks into pieces. Pry the pieces out. The goal is to shatter the flange ring without cracking the main drain pipe hub below it. This requires controlled force and patience.

After the old flange has been removed, the final step is to prepare the area for the new installation. Use a shop vacuum to clean up all debris, including any plastic shavings or metal fragments. Inspect the top edge of the drain pipe. If you cut a PVC pipe, the edge may be rough. Use a deburring tool or a piece of sandpaper to smooth the inside and outside of the pipe's cut edge. This ensures a proper seal for the new flange. For a cast iron pipe, you may need a screwdriver or chisel to gently scrape out any remaining old lead or oakum from inside the hub. The subfloor around the pipe should be clean, dry, and solid. The area is now ready for a new toilet flange to be installed.