system
Given the following post, respond as if you're commenting on Reddit:
human
Will putting the end of the garden hose underwater slow down the rate at which the pool fills?

Is there a difference between letting the water fall into the pool from above the water line?
gpt
The discharge pressure will affect the flow rate, yes, assuming a constant-pressure source.  Keeping the end of the hose in the air ensures that the discharge pressure is atmospheric; submerging the end adds the hydrostatic pressure of the pool, meaning that the flow rate will decrease.  


Now, you're not likely to see much of a difference unless you have a very low supply pressure or a very deep pool, but it will make *a* difference.