I just completed laying irrigation piping (black poly) and by and large it seems solid. I do however have issues with the take-offs from my house's hose bibs, where I have metal risers going into the ground to meet the poly underneath. The "risers" at the start of the system at the sides of the house are stainless steel nipples.
But no matter how much I tighten (with a pipe wrench) and use plumber's tape, the NTP threaded connections between stainless steel nipples and brass reducers (hose-bib end) seems to want to leak. This raises the question, is it a known problem when coupling SS and brass? That their NTP threading isn't exact enough of a match to maintain a dry connection?
I used SS nipples because they were half the price of brass. Was that a mistake?