The plumber has been and gone and I now have a new toilet. The old one was clogged, did not flush well. A masked friend attempted to use an auger but was unsuccessful. The roof stack vents were mentioned as a possible source of the drainage problem and time was spent calling several plumbers, all of whom were busy.
After receiving a recommendation from another plumber, I contacted a 24 hour plumbing concern and was given a slot for later afternoon. A gentleman showed and his assessment was that the roof stacks were not contributing to the problem and that the clog could be resolved with the use of a six foot auger but that the situation was likely to recur because of basic flaws in design.
One was that there was no provision for water to move in the bottom of the bowl via jets. The only water came down from the top and in a low flow bowl, the waste wasn't moving quickly from the bowl through the opening to the outside pipes. Known as a trap way, this can clog easily if the design or the flush meant to clear it are poor.
Though there are standards for the size of the trap way, mine was narrow rather than round, making it more difficult to clear or to insert an auger if necessary.
Two readers did not understand the concern with the roof or what it had to do with inside plumbing. Your stacks are built up into the wall and come out at your rooftop, called vents. If these clog, the drains into your home can be effected and one way this problem manifests is slow drainage of toilets, tubs or sinks. This was the first thing the plumber checked upon entering my flat because I had reported the toilet clearing very slowly. When my sinks and shower cleared without incident, he and I knew the source of the clog was inside rather than at roof level.
I ultimately decided to pull both the toilet and the aging hot water heater. When the toilet came out, roots were discovered in the floor where the flange is located. Those were cleared, but the p trap and tank also contained plant matter so over the almost nine years I've had that toilet it hosted a small ecosystem. From what I read, that isn't uncommon, especially in places like Florida.
After some issues with the height of the toilet, I now have a new Kohler which is comfortable to use and I can report that the hot water is great. The plumber was polite, cleaned up after the job and wore a mask without being asked to do so.