Yes. Compressed air leaves moisture behind in the tank. DEWALT says the DWFP55126 drain valve should be used to drain condensation at the end of each use.
Why water appears in a machine that only pumps air
Air contains water vapor. Compressing and cooling that air causes some moisture to condense inside the tank. Humid weather and long run times can create more water.
Why leaving it there matters
DEWALT warns that water can corrode and weaken the air tank, creating a rupture hazard. This is not cosmetic rust on the outside. The concern is the pressure vessel itself.
A simple end-of-use routine
- Turn the compressor off and unplug it.
- Reduce regulated outlet pressure.
- Disconnect the air tool.
- Place a container where the drain will discharge.
- Bleed tank pressure according to the manual.
- Open the drain and let condensation out.
- Close the drain before the next use.
Follow the exact sequence and residual-pressure guidance in your own manual. Condensate can contain rust or oil residue and may stain surfaces.
If the tank itself leaks
Do not weld, drill or patch a pressure tank. DEWALT’s troubleshooting guidance says a defective tank must be replaced rather than repaired.