I am doing loads of driving at the moment and fill it up quite a lot. I doubt you have a leak. Given the evil spray and salt I need to to use the windscreen washer stuff a lot.

Not sure about the Rain X comments as its completely useless for dirty spray.

 

I recently had the washer pump replaced as it had a leak. Was quite a slow leak but noticed pool of water by driver's front wing when car was parked on a slope with the front lower than the back. On the level it seemd to be held somewhere in the chassis.

 

As an 04 owner have you had the fix done by Honda so that your washers only do the headlights when they are actually on? This mod should be done for free if you complain to your dealer and they also slap an amendment page in your manual.

It has reduced my screen wash consumption significantly but will obviously differing depending on when you drive. The other benefit is reducing the potential for a soaking in the summer with the top down as I find doing the windscreen more controllable.