Here is a great post from the USA  pickleball Refs

https://www.facebook.com/share/p/cd1VjoXwvjuJRHC5/?mibextid=oFDknk

Applying 6.C.6. gap requirements to OUT calls for serves. Are all the following numbered statements true? (Edit: both balls represent serves intended for the right service court. The server if visible would be at the top of the photo beyond the net).

6.C.6. "Players shall not call a ball “OUT” unless they can clearly see a SPACE between THE LINE and the ball as it hits THE GROUND". 

1] "The line" in rule 6C6 refers to the exact edge of the 2" lines that mark the boundaries between IN and OUT territory. 

2] For serves, the 6C6 "line" for three sides is the outer edge of the centerline, baseline, and sideline. The line itself is IN for those three sides.

3] For serves, the fourth 6C6 "line" is the rear edge of the NVZ line that abuts the service court. The line itself is OUT. 

4] "the ground" referred to in rule 6C6 for OUT calls is always in OUT territory, meaning for serves, the OUT territory outside the service court. 

5] "space" in 6C6 refers to a visible gap between the "the line" (the IN/OUT boundary) and the spot where the ball hits "the ground".

6] The white wire in the photo approximately locates 6C6 "the line", the IN/OUT boundary for serves.

7] Both balls in the photo are shown to be in OUT territory for serves.

8] The red pencils approximately show where a required 6C6 "space" gap might be seen for OUT serves falling near the centerline and on the NVZ line.

9] For short serves, the smallest 6C6 space gap will be located on the NVZ line.