I blow mine out add AF and blow it out again add AF to the drains…
People will argue this forever and never settle it… but be sure of one thing, no one that has recommended air only has also offered to guarantee their advice… and while we hear these same silly arguments every fall, every spring we read a lot of post about how to fix the cracked toilets and fix a leaking water line…
In the end it’s your decision, your RV, and your nickel… spent it wisely…
one more thing I have never seen a waterline installed in a RV that would completely drain to one end or the other, or to the low point drains… they always go over or around things leaving plenty of low spots in them…
