I searched a lot but could not find a duplicating issue. So I created a new one.
Background
In 1.12 and earlier versions, it was "harder" to swim up a water stream that was flowing down. It took longer than a stream of source blocks. Downward speed was also faster in falling water.
The bug
In 1.13, now the player sink/swim up speed in downward flowing water is the same as in source blocks. The falling property of the water has no effect. This also affects mobs.
Attachments
Comments 4
After doing some tests in 1.15.1: There is a slight difference in speed, but it's a lot less noticeable.
These are tests of 25 blocks. Numbers are the time in ticks measured with commands.
| Source Blocks | Falling Water |
|---|---|---|
Swimming up | 107 | 130 |
Swimming down | 83 | 74 |
Floating up | 154 | 230 |
Floating down | 958 | 291 |
From these results it is clear that the difference between source blocks and falling water is obvious when you are floating in the water, but almost not noticeable when you are swimming.
Can confirm.