Welcome to the forum.
On the scale of 1 to 10 with 10 meaning glowing red & smoking, I'd call this a 1 that has little chance of growing up to become a 10.
I read your profile & since you are the AHJ, you can waive some requirements by special permission, provided you feel that equivalent safety is being provided.
I'll echo the sentiments in the above post, I'd rather have a water line below.
I'd also get word to the plumber to let him know that he should stay out of this space.
[This message has been edited by Tom (edited 09-17-2002).]
Few things are harder to put up with than the annoyance of a good example.