PVC vs CPVC
The infrequent mention of the use of PVC, here, tends to make me
nervous. There is a special formulation of PVC called "CPVC" that is
always required for "potable water" applications. IMO, that's the only
kind we should consider for any extended contact with our tank water.
Unfortunately, the ANSI standards for CPVC have been deliberately
designed to make it a total non-fit with any ordinary PVC, so a plumber
can't cheat and substitute a PVC fitting that has noxious aromatics in
its formulation. You can't mix and match or adapt from one to the other
(without a machine shop).
It's also sometimes hard to find. I've been running two copies (in
CPVC) of the ancient tube-type UGFs, under 30 mesh sandblasting sand,
for a year or so with no ill effects. The 1/2" size is smaller than
PVC, and just perfect for UGF (USF?) applications. I like it.
Wright Huntley (408) 248-5905 Santa Clara, CA USA huntley at ix_netcom.com