After clearing out the overflow pipe, I still had a problem because water has started dripping in places not directly over the drain pan.

I "extended" the coverage with sheet metal, but the water is still dripping from somewhere that I can not yet see. I looked inside the condenser housing (which is directly above the pan) and saw that water is standing there.

Is there supposed to be a drain hole somewhere on the bottom of this sheet metal housing? (Water backing up in there might be getting deep enough to flow into the much larger distribution box where the ducts connect.)

1 Answer 1


A drip pan backing up is very common. Look for the drain, there is probably some growth of moss / mildew and dust growing in the drain. Don’t use vinegar to clean it vinegar will Dissolve the galvanized coating over multiple uses and is hard on the coils. The drain is usually on the outside edge and I always tilt the pan so that is the low point.

  • I had forgotten that the drip pan that I "solved" was actually just a back-up system. I found the drain in the condenser housing- on the opposite side from the drip pan overflow drain. You said not to use vinegar, so what should I use? I have some generic bleach for laundry. The active ingredient is sodium hypochlorite 6%. Can I use that, diluted? How often should I treat it to avoid a repeat problem? Aug 9, 2020 at 23:46
  • Bleach would be better than vinegar it should not take much , remember that is in your air return so even a small amount may have your house smelling strong. There are some tablets that will do the same with no smell “pan tablets” 1 every month during cooling season I think they may last longer on some systems but I am usually only using them about 3 months a year. You can get them online or big box stores , I just wanted to give a heads up on the bleach I put a couple cups in years ago and my house smelled like a swimming pool for a week.
    – Ed Beal
    Aug 10, 2020 at 0:49

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