As Roto Rooter was the company to put in the new leach field last year (just before we bought the house), there is a chance that this will all be under warranty. Even though that idea was suggested by the person I contacted, I realize that having this fixed for free is mostly wishful thinking on my part. Still, I would prefer to know for certain rather than go with another (although possibly less-expensive) company. We will find out more tomorrow.
I certainly hope that this will not be an annual stress.