air line water
You could do what i did when i had the same thing at a bodyshop that i owned. I took and old drive shaft[the bigger the better]put a petcock on one end for a drain. Then ran my air line in at the center of shaft. Next i took my air off a fitting that i'd put at the top of shaft.Worked great no more water in my paint jobs. I still used a water fillter after my home made water tap. The idea is water is heavyer than air. So when it enters open space in drive shaft it'll fall to bottom of shaft and clean air goes to top of shaft.After a hot summer day you would'nt believe how much water would come out of that drive shaft.