Thanks for the response. Flushed the tank and replaced anode at the beginning of November. Been using it since then, and it just started tonight, or more properly, just heard it inside tonight. I switched form city water to the pump, and no cycling occurred, so probably no water leak.
Elliott & Vicky, and Sadie the GSD copilot
2014 36RE, Onan, Titan disc brakes, 17.5 inch Sailun H tires, lots of other options
2013 RAM 3500 CC, LB, DRW, Cummins, AISIN, 4x4