On Feb 8, 9:52*pm, croy wrote:
I've searched a lot on the web, but can't find an
explanation as to the difference between white and gray PVC,
nor why the gray is for outdoor use only, nor whether either
are ok for drinking water applications. *Even the Dura
website was silent on this.

All this hullabaloo over two $15 nipples?

The brass nipples are the right part, right now. You can order them
online cheaper, but that delays the deployment of your filter. All to
save $20. If that much.

I would buy the nipples, grumble about the price, install them, get
over it, and enjoy the water filter.