Toilet is Loose
If your toilet rocks even a little, it could be due to a damaged flange. Before removing the toilet from the floor, check all connections and bolts to ensure they are tight. Neglecting to secure a loose toilet could damage a flange that may not need to be replaced.
The toilet is Leaking at the Base
In most cases, it is the wax ring that needs replacing if your toilet leaks at the bottom. But to be sure, remove the toilet to inspect both the flange and wax ring. Never attempt to “seal” the toilet leak with some kind of sealing material that prevents water from leaking. While the water may no longer be leaking onto your floor, it is leaking somewhere and that somewhere is underneath the floor.
Don’t Know When and If the Flange Has Ever Been Replaced
Proactively avoiding expensive home or commercial building repairs means replacing questionable plumbing components. If the previous owner says they never had any problems with the toilet, chances are the toilet flange and wax ring are old and nearing their end life.
Your Bathroom Smells Like a Sewer
Rotten egg or sulfuric odors in your bathroom without leakage at the base of your toilet could mean the flange is broken just enough to let sewer line odors to infiltrate your bathroom. If not replaced, a cracked flange will eventually allow water to leak from the bottom of the toilet.