How to Replace a Toilet Flange: Step-by-Step

Why the flange matters

The toilet flange is the fitting that connects your toilet to the drain line. It anchors the toilet to the floor and provides a surface for the wax ring or rubber gasket to seal against. If the flange cracks, rusts, or sinks below the finished floor, it can cause leaks, odors, and a wobbly toilet.

You can learn more about the flange's role in toilet flange basics. Knowing the difference between PVC and cast iron flanges will help you choose a replacement that matches your drain pipe.

Signs your flange needs replacing

Not every leak or wobble is a flange problem, but a broken flange has a few telltale signs:

Water pooling around the base of the toilet, especially after flushing.

A persistent sewer smell even after you replace the wax ring.

The toilet rocks slightly even when the floor bolts are tight.

Cracked or missing pieces of the flange visible around the drain opening.

If your flange is simply too low, you might not need a full replacement. Read about toilet flange recessed below floor and flange extenders before you start cutting.

Tools and materials

For most flange replacements, you'll need a few basic hand tools: an adjustable wrench or pliers, a screwdriver or socket set for the floor bolts, a putty knife or scraper to remove the old wax ring, and a rag or sponge for cleanup.

You'll also need the new flange itself. Flanges come in several materials, and the right choice depends on your drain pipe. You will also need a new wax ring or rubber gasket; see toilet wax ring vs rubber gasket to decide which is better for your situation.

Step-by-step: Removing the old flange

Start by turning off the water supply and flushing the toilet to empty the tank and bowl. Disconnect the supply line, then remove the floor bolts and lift the toilet straight up to avoid cracking the base. Set it aside on a drop cloth.

Scrape away the old wax ring from the flange and the toilet horn. Remove any old bolts and screws. If the flange is screwed to the subfloor, use a screwdriver or drill to back them out. For a cast iron flange that is leaded or screwed into the pipe, you may need to cut it with a close-quarter saw. Work carefully to avoid damaging the drain pipe itself.

Once the flange is free, inspect the drain pipe. If the pipe is cracked or has a broken hub, you may need to cut back to a clean section. That is a more involved repair, and you may want a professional. If the pipe is sound, you're ready to install the new flange.

Step-by-step: Installing the new flange

Clean the area around the drain pipe so the new flange can seat flat against the subfloor. Most flanges have a hub that slides over the pipe or inside it. Follow the manufacturer's instructions for your flange type, but in general you want the flange to sit so the top edge is flush with the finished floor or just slightly above it.

Secure the flange to the subfloor with the screws provided. If the subfloor is concrete, you'll likely need to use a flange with a concrete anchor kit or set the screws in masonry anchors. The goal is a rigid, non-moving base for the toilet.

If the flange ends up too high or too low, you can address that later. Once the flange is secure, install a new wax ring or rubber gasket onto the flange, then carefully lower the toilet over the bolts. Press down gently to seat the wax, then tighten the nuts evenly. Reconnect the supply line, turn on the water, and test for leaks.

If you're already lifting the toilet, consider upgrading to a high-efficiency 1.28 GPF model to save water. Review our toilet installation guide for the full process if you decide to replace the toilet as well.

When to call a professional

A flange replacement is a doable DIY project for many homeowners, but there are exceptions. If the drain pipe is corroded, if the subfloor is rotted, or if you discover that the flange is not centered under the toilet's outlet, you may need a plumber or a flooring repair.

Also, if the toilet itself is old and inefficient, you might consider replacing it while the area is exposed. A WaterSense labeled model uses less water and performs well. If you're already lifting the toilet, upgrading to a more efficient model could save water without sacrificing performance.

What to pick for your use

Questions

How do I know if my toilet flange is broken?

Common signs include a wobbly toilet, water pooling at the base, sewer odors, or visible cracks around the drain opening. If you see these symptoms after ruling out a wax ring leak, the flange itself is likely the culprit.

Can I replace a toilet flange without removing the toilet?

No. The toilet must be lifted to access the flange. You cannot properly remove the old flange or install a new one while the toilet is in place.

Should I use a wax ring or a rubber gasket with a new flange?

Both work. A rubber gasket is reusable and easier to seat correctly, but you must clean the mating surfaces well. A wax ring is more forgiving of slight flange height variations. See the comparison of wax rings and rubber gaskets for a detailed breakdown.

What if the new flange sits too low or too high?

If the flange is recessed below the finished floor, you can use a flange extender. If it sits higher than the floor, the toilet may rock; you may need to set the flange deeper. Follow the guidance on fixing flange height issues for each scenario.

Can I use the old floor bolts?

It is best to replace them. Old bolts can corrode or strip over time. New bolts are inexpensive and ensure a secure hold. Brass and stainless steel bolts offer different levels of corrosion resistance, so choose based on your environment.