I have a 1.5 HP two tank compressor that I have to drain daily.

What is the most efficient trap to capture the water oil mixture as I drain it?

  • Single plug underneath? If so, I drain my single-tank into a disposable aluminum pie tin (i reuse it, just keep a shop rag on it) after unplugging power, dropping the pressure down to about 20-30 psi internal using my blowgun attachment and letting it sit for a bit, then pour the condensate into an old compressor oil bottle to be dropped off for disposal. If necessary, you can probably fit a temporary plastic hose to act as a drain line if the plug is higher/in an awkward position. Just my 2 cents. – Jacob S Jul 16 '13 at 16:54
  • Two plugs actually, one for each tank. Thanks for the info. Why don't you drop the internal pressure all the way to zero? – l3win Jul 17 '13 at 18:28
  • Having air movement helps to force the condensate out. Fun experiment -- fill two cups with ice water and allow to form condensate. Hold one and blow compressed air over it -- then check which of the two cups has more water stuck to the outside. :-) In essence, the air movement helps smaller drops overcome friction -- but all in all, it is a personal preference. Lowering the pressure just decreases the amount of blowing around the water does in the tin. – Jacob S Jul 17 '13 at 18:59

You don't fully open the drain. If you do, the air pressure will create a vortex and stop it from draining. Crack it open until it spits and starts coughing up air, then cut it back some until all it's doing is gurgling.

Repeat until you can't get it to gurgle anymore.

Pipe it with some flexible copper to a nearby drain for simplicity.


There are automatic drain valves for compressors that screw in at the bottom of the tank and periodically let small amounts of water and air out. You could screw hose on their exit port and route it to some container (just make sure that water needs to flow down, not up)

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