Water supply slope

[Airjordanbl23]

This may be an odd question. I known that drain pipes are supposed to be sloped a certain amount. What about water supply pipes? Should water supply pipes be level across the system or sloped one way or the other?

 

[Sarg]

First answer is ...... if you have a need to drain your system to prevent freezing the answer would be Yes.... It would help.
If not ... then NO.