Leak could be anywhere there is a water line. We had a tiny leak on the supply line to hot water heater and didn't notice and did a lot of damage before we found out it was leaking. Also last time we used city water connection many years ago. Don't use city water connection anymore at all. We work off from self contained, your pump should sing to you when it's pushing water. If it sings an no water on, guess what? Pump is pushing water somewhere. From weak diaphragm in water pump to loose connection that only needs a turn to stop water leak.