How do I empty a bucket in Vintage Story?

Ctrl + right-click will empty the bucket.

This needs to be done against a normal block in the world (not a barrel, and not empty air).

• If the bucket contains something other than water (e.g. tannin), the contents will be destroyed and you'll have an empty bucket.
• If the bucket contains less than 10 litres of water, the water will be destroyed and you'll have an empty bucket.
• If the bucket contains 10 litres of water, a water source block will be created in the world and you'll have an empty bucket. Make sure you do this in a place where the resulting flood won't cause problems.

I haven't found a simple way to empty a full water bucket without creating a water source block, but here are a few ways you can deal with it:

• Place another block (e.g. soil) in the water source block to destroy it.
• Empty the bucket into an existing water source block. This won't create a new source block.
• Partially empty the bucket into an empty barrel (Ctrl + right-click over the barrel to empty 1 litre at a time). Then empty the rest of the bucket into the ground, fill from the barrel, and empty into the ground.