What a closet flange does and why it fails
A closet flange is the ring that sits where your toilet connects to the drain line below the floor. On PVC pipe, it bolts to the floor and seals the gap between the toilet base and the opening in your subfloor. The flange itself wears out — the wax ring compresses, the bolts corrode, or the plastic cracks from weight or age — and when it does, water leaks into the subfloor and rots the wood underneath.
Replacing it is a straightforward job if you have basic tools and do not mind working around a toilet. The hardest part is usually getting the old flange out cleanly without damaging the PVC pipe below it. If the pipe is damaged during removal, you will need to cut it shorter and use a repair coupling, which adds a step but is still manageable.
Key Takeaways
- Turn off the water, empty the tank, and unbolt the toilet from the floor before you start.
- Scrape out the old wax ring and flange bolts, then remove the flange itself by cutting it away or unbolting it if it is screwed down.
- Inspect the PVC pipe for cracks or damage; if it is damaged, cut it back and install a repair coupling before fitting the new flange.
- Slide the new flange onto the pipe, level it so the bolt holes are parallel to the wall, and find it with the fasteners that come with it.
- Set a new wax ring on the flange, lower the toilet back down, and bolt it to the floor before reconnecting the water supply.
Tools and materials you will need
Gather these before you start: a wrench or adjustable wrench, a putty knife or scraper, a hacksaw or PVC cutter, a level, a flashlight, and a bucket. You will also need a new closet flange (make sure it matches your pipe diameter — usually 3 or 4 inches), a new wax ring, new closet bolts if the old ones are corroded, and possibly a repair coupling if the pipe is damaged.
If the old flange is glued to the pipe, you may need a reciprocating saw or a fine-toothed handsaw to cut it away. If it is bolted down, a socket wrench will speed the job. Have a rag or old towel on hand to catch water that drains from the trap when you remove the toilet.
Removing the toilet and old flange
Turn off the water supply at the shutoff valve behind or below the toilet. Flush to empty the tank, then use a sponge or wet/dry vacuum to remove any remaining water from the bowl and tank. Disconnect the water line from the fill valve by turning the compression nut counterclockwise by hand or with a wrench.
Unbolt the toilet from the floor by removing the nuts on the closet bolts — usually two bolts, one on each side near the back. Rock the toilet gently side to side to break the seal of the old wax ring, then lift it straight up and set it on its side on a towel or in a bathtub. Water will spill, so be ready.
Once the toilet is out, scrape away the old wax ring with a putty knife. Get it down to bare floor and flange. If the flange is bolted down from above, remove those bolts now. If it is glued to the PVC pipe, you will need to cut it away.
Cutting out the old flange and inspecting the pipe
If the flange is glued to the PVC, use a hacksaw or reciprocating saw to cut through the flange ring just above the pipe. Make the cut as close to the top of the pipe as you can without gouging the pipe itself. Once the ring is cut, you can pry it away with a screwdriver or putty knife and pull out any remaining bolts or fasteners.
Shine a flashlight down into the pipe and look for cracks, splits, or damage to the walls. If the pipe is intact and smooth, you are ready to fit the new flange. If there are cracks or if the pipe is damaged where the old flange was cut, you will need to cut the pipe back to sound material and install a repair coupling.
To use a repair coupling, measure how much pipe you need to remove, then use a hacksaw to cut the PVC straight across. Dry-fit the repair coupling (also called a slip coupling) over the cut end, then measure down from the top of the pipe to mark where the new flange will sit. The flange should rest on the floor or subfloor, not float above it.
Installing the new flange on intact pipe
Slide the new flange onto the PVC pipe. It should fit snugly; if it is too loose, the flange will rock when you bolt the toilet down. Most new flanges come with a rubber gasket or are designed to sit directly on the pipe. Check the instructions that come with your flange.
Use a level to make sure the flange is sitting flat and the bolt holes are parallel to the wall behind the toilet. If the flange is tilted, the toilet will rock and the wax ring will not seal. Rotate the flange so the bolt holes point toward the wall, not toward the center of the room.
find the flange to the floor or subfloor using the fasteners provided — usually stainless steel screws or bolts. Drill pilot holes first if you are screwing into hardwood or concrete. Do not overtighten; you only need enough pressure to hold the flange in place. If the flange has a set screw that tightens onto the pipe, snug it down by hand, then give it a quarter turn with a wrench.
Setting the wax ring and reinstalling the toilet
Place a new wax ring on top of the flange, centered over the opening. Press it down gently so it sticks to the flange. Some wax rings have a plastic horn that points down into the pipe; others are flat. Either type works, but make sure the ring is seated all the way around.
Carefully lower the toilet back onto the flange, aligning the bolt holes with the closet bolts sticking up from the flange. Press down evenly and firmly until the toilet base sits flat on the floor. You should feel the wax ring compress slightly. Do not rock the toilet back and forth once it is down — this breaks the seal.
Thread the nuts onto the closet bolts and tighten them by hand first, then with a wrench. Tighten in a cross pattern — one side, then the opposite side — to keep the toilet level. Tighten until the nuts are snug, but do not over-tighten or you will crack the porcelain. The toilet should not move when you push on it.
Reconnecting water and testing for leaks
Reconnect the water line to the fill valve and turn the shutoff valve back on. Let the tank fill, then flush a few times to make sure water flows normally. Watch under the toilet from below (or have someone else look) to check for leaks around the base where the flange meets the floor.
If water drips from the bolts or around the edge of the base, the wax ring may not have sealed properly. This usually means the flange was not level or the toilet was rocked after it was set. You will need to remove the toilet, scrape away the old wax ring, and try again with a new one. If the leak is coming from inside the bowl or from the tank, the problem is with the fill valve or flush valve, not the flange.
Let the toilet sit for 24 hours before using it heavily. Check again the next day for any signs of water under the floor or around the base. If everything is dry, the job is done.
Frequently Asked Questions
What if the PVC pipe is cracked when I remove the old flange?
Cut the pipe back to solid material using a hacksaw, then install a slip coupling (repair coupling) over the cut end. Slide the new flange onto the pipe above the coupling. The coupling lets you join two pieces of PVC without needing to glue them, which is faster and does not require you to wait for adhesive to cure.
Can I reuse the old wax ring?
No. Wax rings compress and harden over time and will not seal properly a second time. Always use a new wax ring when you reinstall the toilet. They cost a few dollars and are the most common source of leaks when people try to save money.
How do I know if my flange is the right size?
Measure the outside diameter of the PVC pipe — it is usually 3 or 4 inches. The flange must fit that pipe size. Bring a photo or the old flange to the hardware store if you are unsure. Flanges are not one-size-fits-all, and using the wrong size will cause leaks.
What if the flange is stuck to the pipe with PVC cement?
Use a hacksaw to cut through the flange ring just above the pipe, then pry away the pieces. Do not try to unglue it — PVC cement creates a permanent bond. Cutting is faster and cleaner than trying to dissolve the joint.
Do I need to caulk around the base of the toilet after reinstalling it?
Caulking is optional but recommended. Use a silicone caulk (not acrylic) around the base where the toilet meets the floor, leaving a small gap at the back so water can drain if a leak occurs. This keeps debris and moisture from getting under the toilet base.