I can’t think of any other way to determine if a water pump is ON/OFF other than using a current sensor like ACS712. I would then not only have a power consumption but also how much time it works during the day.
Probably there’s an easier way?
There are several different alternatives.
Vibration sensor
Pressure sensor (depending if the system hold pressure)
Rotation sensor (could be as simple as an eye pointed at a shaft with a piece of reflective tape)
A simple device (adapted for voltage) that is only powered when pump is running; easiest would be a relay with an aux contact.
If there is any indicating lights, then a photosensor to sense the light on therefore running.
Need more details to give you more options, but a current sensor is far from your only option. What is the purpose of the water pump; is it commanded via something else; what voltage; do you control it manual or automatically?
It is controlled automatically by a two-buoy on the main and underground water tank and it pumps water from an underground tank when needed.
Something like this:
Or this (it’s in Spanish)
The buoy circuit runs on 24Vac, but what triggered the need of knowing when the pump was working or not and for how long, was the fact that a couple of months ago, the previous pump failed and remained on for a long period of time, and finally died.
I want to be alerted before that happens again and eventually turn it off remotely.
I have a pressure (depth) sensor which when there is a rapid drop implies the motor; I have a pressure sensor in the pipe and I am about to put in a Shelly EM plus clamp that will tell when the motor is drawing power AND control the contactor for the pump. I was going to use Shelly 2PM Pro but realised that my 4.1 Amp motor actually has a start current of at least 16A. Too much for a Shelly. There will be automation to turn off pump of it running over a certain time period AND the tank goes below a certain level. I might also turn the motor off if the depth sensor goes offline
To be honest, I don’t want to make changes to something that works 
I just want to add an extra layer of security to it. Knowing if the pump is working for X amount of time (I know it takes 10 min at most to fill up the upper tank) will be sufficient to cover my need.
I implemented something similar to this to determine the water level:
Easier way: