• Find or create small lake with lilypads.

• Get one water bucket.

• Make sure you are not on top of the lilypad. You can stay build 1-2 blocks pillar up and stay on it.

• Right click with the Water Blucket on top of the lilypad.

• The Water appears for 1 Second and Disappears.

• The bucket is Empty now. Right click with the Empty Bucket somewere on the ground and see it's not a glitch and the water appears again, the water removed total.

• The bug works too on the side on lilypads;

(I don't know, I don't tested the bug with dispensers placing water, so I can't tell this will work / not work with dispensers)