Originally Posted by Sethticlees

I found a leak under my glove box once. Actually, water was getting in around the windshields lower splashguard (also known as the cowl cover/ or grill). Anyway, I had to remove the wiper arms and then remove the cowl cover.
To find the leak I poured a tiny bit of water down the windshield and checked under my glove box for the puddle. Immediately, I noticed a stream of water trickling down from around the kick panels and traced the source to a retaining clip located in the top of the cowl.

I guess the retaining clips hold the cowl cover into place or something. One was loose and had lost its sticky contact underneath so water was able to leak past the clip down into the car then drip on all the coolant/HAVAC lines and finally puddle on the floor under my glove box.

Check around the cowl cover for a possible leak would be my suggestion.