I live in the pacific northwest where it rains a lot and humidity is high during the winter. I drain the entire system every month, did it yesterday in fact. Each drop on your pipe should have a valve too to evacuate the moisture, hopefully any hard piping has slope on it so it can be drained too. A long time friend had his under the floor of his residence, it had been there for 30 years, the compressor started cycling more frequently, so he went under there to see what was going on. The 30 gallon tank was full of water, he never drained it. Petcock was corroded shut. He got a quick lesson that water weighs 8 pounds per gallon when he hauled it out of the crawlspace. On a good note, since it was full of water, it didnt have much volume of compressed air if it let go. Plumbers fill the waste plumbing with water and use very little air to test because if a pipe let go, compressed air and plastic pipe can be shrapnel city.
1953 Chevrolet 3100261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY GalleryVideo of the 261 running1964 GMC 1000305 Big Block V6, sm420, the next cab off restoration
