[OkayPhysicist]

The water analogy works because circuits are linear systems. Pretty much all linear systems can be modeled that way, if you're willing to contort things the right way.

[sobriquet9]

Water analogy works well even with non-linear components like diodes (think one-way valve) and transistors (think valve controlled by water pressure from separate tube).

[magicalhippo]

Works other way too. For me the explanation of a hydraulic ram pump[1] clicked when I realized it's essentially just like a boost converter[2].

[1]: https://en.wikipedia.org/wiki/Hydraulic_ram

[2]: https://en.wikipedia.org/wiki/Boost_converter