Signs the flange is the problem
Check these before you replace the toilet
- The toilet rocks even after you tighten the closet bolts.
- Water or a stain appears around the base after flushing.
- A sewer smell comes from the bathroom floor and the bowl is dry.
- The floor around the toilet feels soft or spongy underfoot.
- The ring is cracked, rusted through or the bolt slots have snapped.
A leak at the base can also come from a worn wax ring or a loose bolt. The only way to tell is to lift the toilet and look at the flange itself. If the floor is soft, stop using the toilet and call, because the subfloor may need repair before any flange is set.
Where the flange belongs
The flange should sit on top of the finished floor surface, not below it. When tile or new flooring goes in after the flange was set, the ring can end up low, and the wax ring then cannot seal. The usual fix is a spacer or an extension ring, or a flange reset at the correct height.
The center of the drain opening is usually about 12 inches from the finished wall, which is the standard rough-in for most toilets. Check the box for your toilet, because a 10 inch or 14 inch model needs a different spot.
| What you see | Likely cause | Typical repair |
|---|---|---|
| Toilet rocks | Loose flange or low flange | Anchor the flange to the subfloor, add a spacer |
| Cracked or broken ring | Age or overtightened bolts | Repair ring or replace flange |
| Leak at the base | Failed wax ring or low flange | Reset the toilet with a new seal at the right height |
| Rotted subfloor | Long-term slow leak | Cut out and rebuild the subfloor, then set a new flange |
| Flange higher than floor | Floor installed over it | Set the toilet with a taller seal or trim the flange per the manual |
Materials, and why they matter
Flanges come in PVC, ABS, cast iron and brass, and stainless repair rings exist for flanges with broken bolt slots. The ring has to match the drain pipe material and size, typically a 3 inch or 4 inch connection. Gluing the wrong plastic to the wrong pipe is a failure that shows up months later.
A repair ring is a legitimate fix when the pipe below is sound and the flange is only cracked. A new flange cut into the drain is the better answer when the pipe itself is damaged, which is where a camera or a look from the crawlspace helps.
What a toilet flange change means for permits
North Carolina uses the 2024 North Carolina Plumbing Code, which became mandatory on July 1, 2025 and is based on the 2021 International Plumbing Code with state amendments.
The Town of Morrisville says a plumbing permit is required for installation, extension, relocation or replacement of a plumbing system, while minor fixture repairs that do not disrupt water supply, waste or vent may be exempt. Resetting a toilet on a sound flange is a fixture matter. Cutting out drain pipe or moving the toilet is not, so call the Inspections Department at 919-463-6190 before work like that.
Source: Town of Morrisville Residential Inspections page and NC Office of State Fire Marshal code effective date, checked October 2026.
How we reset or replace a flange
- 01
Shut off and drain
We close the toilet supply, flush, and sponge out the bowl and tank so nothing spills on the floor.
- 02
Lift and inspect
We remove the toilet and the old wax, then check the ring, bolt slots, pipe and subfloor.
- 03
Repair or replace
A repair ring covers a cracked flange on sound pipe. A cut-in flange is used when the pipe is damaged.
- 04
Secure to the subfloor
We use corrosion-resistant screws into solid wood, never into soft or rotted material.
- 05
Set with a new seal
A fresh wax ring or a rubber seal goes on, the toilet is lowered straight down, and we test for rocking and leaks.
Do it yourself, or call?
Resetting a toilet on a good flange is a reasonable weekend job. Replacing a flange that is attached to a cast iron or buried line is not, because the cut and the connection must be watertight and set at the right depth.
If the work reveals a damaged drain below the floor, that moves into plumbing installation and repair territory. A sewer smell after the reset can also point to a venting problem, and we cover the fixture side under toilet repair.
Bolts, torque and the small details
Tighten the closet bolts evenly and stop when the toilet feels snug. Porcelain cracks if it is overtightened. Check the toilet is level in both directions before you cap the bolts.
A plastic bolt cap that sits proud of the porcelain can tell you the bolt is too long, and a hacksaw cut with a clean edge fixes it. A flange with one bolt slot snapped can still hold with a repair ring, but only when the other slots are sound.
Choosing the right flange for the job
A plain PVC flange is fine for a clean cut-in on plastic drain pipe. A cast iron or brass flange suits a cast iron stack but is heavier and harder to cut. A stainless repair ring is the right call when the flange has cracked but the pipe is solid.
Offset flanges exist for a toilet that needs to shift an inch or two, but they restrict flow slightly and are a last resort. If the toilet is in the wrong place, a plumber can explain whether a shift or a true relocation is the honest answer.
Why the wax ring gets blamed
Most flange problems get blamed on the wax ring because that is the part people see. A new ring will fail again if the flange is low, loose or tilted. Resetting with the same flange condition just repeats the leak.
That is why we inspect the flange before we replace the seal. If you are on the Durham side of the county line, see our Durham plumbing page for how dispatch works there.
Call (919) 944-7281 and we can lift the toilet, check the flange and tell you what the repair involves.
Questions about this topic
It should sit on top of the finished floor. A flange below the floor surface will not hold the wax ring seal, and a spacer or reset is the fix.
A repair ring can sit over a cracked flange when the pipe is sound. If the pipe is damaged, a new flange has to be connected to the drain properly.
The flange is probably loose, low or broken. Tightening harder cracks the porcelain, so lift the toilet and look.
Minor fixture repairs may be exempt, but cutting into the drain is different. Ask the Town of Morrisville Inspections Department at 919-463-6190.
A soft or spongy feel around the base, a dark stain or a musty smell usually means yes. Stop using the toilet and have it checked.
A repair ring on sound pipe is often quick. Subfloor work or a cut-in flange takes longer, and we explain which applies after we lift the toilet.