In my jurisdiction, a waste drain vent pipe must terminate 6" above the roof (or another vertical surface if it's not sloped). Is this typically measured on the ridge side or the eave side? For a 4" vent (like mine), it would mean a difference of about 2.5" on my 7/12 roof.
It's measured on the high side (the nearest point or the shortest dimension).
Vent pipes shall terminate not less than 6 inches above the roof, measured from the highest point where the vent intersects the roof.