Said It Here

How to tell if an old toilet flange needs replacing when retiling

When retiling a bathroom, homeowners often uncover old plumbing and struggle to know whether existing cast iron flanges and pipes are safe to reuse or need replacement. Without clear guidance on evaluating their condition, it is difficult to know how to safely proceed with installing new wax rings and bolts.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    scraping off old wax ring detritus
  2. 2
    asking online recommendations for how to proceed with installation
  3. 3
    Leaving old non-leaking pipes alone
  4. 4
    Cleaning off oxidation manually

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/Plumbing2 people · September 2026

“Are these pipes ok? Do they need to be replaced?”source ↗

“The pipes going up the wall to the water heater are not affixed to anything. Do they need support?”source ↗

Srm5918milo · r/Plumbing · 2 upvotes

“As above. Retiling the bathroom, and I was prepping to install the new wax ring. Recommendations as to how to proceed?”source ↗

“If it's fine enough (i.e. won't fail), how do I proceed with installing the new bolts?”source ↗

Ok-Caregiver-2826 · r/Plumbing

Where this came up

People with this problem also raised