I agree to some extent, because the only water that would or could escape would be that in the lines & flowing to the lowest point.
On the other hand, you may not discover a small leak for sometime under those conditions.
You would however become aware of a possible leak much sooner if the pump switch was on constantly because the pump would continually cycle, alerting you that there is a problem.
I'm an expert in only one field....I believe it's somewhere in Kansas.
2000 / 22' SKYLINE NOMAD LITE
1998 DODGE DAKOTA / 5.2L= 8mpg.
2006 POLARIS ATV
1500/1200 Watt Champion generator
Yada Wireless Back Up Camera
1998 Dyna Wide Glide
USMC 68-74