I need help! How do I seal a leak from my overhead tank filled with water with out throwing away or draining the tank? My tank is made from steel.

  • Why can't you drain the tank?
    – Steven
    Commented Apr 24, 2014 at 16:47
  • 1
    where is the leak and what is its form (a pinhole, rustout, seam leak, etc)?
    – bib
    Commented Apr 24, 2014 at 16:51

2 Answers 2


There is underwater epoxy adhesive available for emergency boat repair. You can use the reinforced PVC material used for inflatable boats as a patch material. The catch is the patch must be applied to the inside of the tank so water pressure holds it in place. Applying to the outside will not work because water will push through an outlet path before the adhesive cures.

How long can you hold your breath? If this is for human drinking water, you should disinfect the water after someone has been swimming in it, on top of sanitizing the person before entry.


Several approaches can be used. Which you choose depends on the specific situation.

  • Drive a screw directly into a pinhole leak. Or a wooden dowel. This should not be attempted if there is significant pressure present inside the vessel since expanding the hole for a good seal could rupture the tank.
  • Braze or tack weld sheet metal over a series of holes, fissure or crack on the outside. It would be better to do this on the inside for longevity.
  • Spread roofing leak repair goo over small defects inside the tank. This probably isn't suitable for drinking water, but most other water uses should be okay.

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