Didn't know about the water trick, guess even the porn industry has "special effects"It's not that simple. There's not been much in terms of studies in this regard. What you see in porn is usually pee (or just water pumped into the vagina). There seem to be women that do release urine when orgasming which is then considered squirting and can be quite a lot. On the other hand, I personally know a girl that does squirt regularly and it's only a small amount of fluid and that is quite certainly not urine, but only the secrete of the Skene's gland.
Personally think you might have better odds of finding a nun to date, (did that once didn't know til later ) But that seems a frequent occurrence also , much as the the common occurrence of having an all female drop dead gorgeous family of virgins who only want sex with their son/brother/nephew