As a fueler I can say that we do a check before we start our daily fuellings, and then we check the fuel for water after every fuelling sometimes it's checked whilst fuelling..
On the water front we were tasked to De-fuel a 330 (a few years back). Before we can do this we require a water free sample before starting, on this defuel almost 4 220 ltr drums were filled before we got our clean sample
The only time you find water in fuel is in A/C tanks, and in some cases enough fuel can give poor FQI readings.
Can't say that I've ever seen an engineer do a daily check
Fuel Boy