Back in 2001, a few months after buying a first home and moving in, a problem arose when we had a disposal installed in the sink in the 1950s-era kitchen. Within a few weeks, the sink started backing up, and we called a plumber to investigate. It turned out a pipe in the basement was blocked. After working for a while, the plumber called me downstairs. He had disconnected the pipe at a joint, or maybe he had even sawed it in half, I can’t remember. Anyway, he showed me the in