Every winter, Rhino Rooter gets calls from homeowners in Belmont, Newton, Lexington, Cambridge and nearby communities dealing with frozen pipes, sewer backups, and water heater failures. In many cases, the problem didn’t start overnight. A drain may have been running slowly for weeks. A basement pipe may have been exposed to cold drafts. A water heater may have been making noise long before it stopped working. Then a stretch of freezing weather pushes the system past its brea