The most common toilet problem here is a quiet one — a toilet running continuously and adding to a bill nobody has questioned.
Old flanges in old houses
In pre-war homes the closet flange is often cast iron and has corroded, so the toilet rocks and the wax seal fails. Water then goes into the subfloor rather than the bowl. On original hardwood or tile, this is worth attending to immediately rather than living with a wobble.
Builder-grade fixtures in newer builds
Post-1996 housing went in with entry-level fittings that are now failing on a similar schedule. If yours is original and needing repeated parts, replacement is usually better value than a third repair.
Rental turnover
For tenanted property, replacing an ageing toilet between tenants costs a fraction of an emergency call with an occupant in place and water on the floor.
Rocking, leaking or sweating
A toilet that moves has already failed at the seal. Condensation on the tank in Lowcountry humidity is normal, but persistent water at the base is not.