As well as reducing the temp of the cabin air, a/c removes water vapour from the air. It's the humidity that can make a hot day unbearable. The water you are seeing is a sign that there is more water in the air and the a/c is doing its job by removing it and dumping it overboard.
Tony

mine has been pissing out the bottom the last couple of days. on my c is comes out at the back of the engine bay

coz its working alot harder

my air con drips when I turn it on in the summer. Nothing to worry about

if u use ur ac alot rember to get it re gassed as it will work alot better and if left can be fatal as it can giv off poisinous gasses.

they all do this.

i think youve answered your own question. i rekon its the condensed water that comes off the air con unit cos its soo cold.
mine drips sometimes but only on a sweltering day,if ive been usin it all day (hope im right cos otherwise mines fooked too!)

My mum has a toyota avensis with air conditioning.

It is leaking water from underneath somewhere near the gearbox but the header tank for the coolant system is not looking to be going down.

I'm not an expert on air conditioning in cars but could it simply be the condensation from the air con and not a leak at all?