Here's what I did but I am super anal about water in the system since I use it to paint.
I put a ball valve at the bottom of the tank with clear tubing so you can see what comes out. I drain the tank every other day. Have a dehumidifier in the room too. In the summer, it can suck up a gallon of water every two-threesdays which seems shocking in a second story, closed room. How all that water gets in is beyond me.
First time I drained the tank after first few months of use, at least 2 gallons of rusty water came out. After that I put the ball valve in.
Even with that protocol, you'd be surprised how much water can get into the system.
Second pic is the line that goes up from the compressor into the ceiling and down to the Rapid Air system. In the summer I can open that valve midday and get a decent spray of water.
Then the filtration system. I take the first water trap off every day and let the canister and filter dry out. Even doing that, I have to revive the desiccant once a month.
It is amazing how much water gets into a system. My compressor, 80 gallon tank, runs at least 20 times a day for short periods each time to refill the system.
