I cannot find a rule that permits this, but here is my question....

At the high school level, are double hits allowed:
(a) on serve reception?
(b) on an attack (w/ signifigant downward force) by the opposing team?

Double hits are legal, as far as the rules are concerned iternationally and in Canada not sure about USVBA, on any 'first' contact only. On subsequent contacts they are not allowed. Thus legal on serve or ANY ball played over the net to your side(not just hard driven(beach rule)).

I am kind of looking for the ruling by the NFHS. Would it be the same? Double hits are allowed on first contact? And what about first contact off of a block deflection?

Just wondering.

SportsPlayByPlay

Same I would think, because most everybody takes their cues from the FIVB. First contact off a block is still a first contact(block is not counted as a contact).

double hits
 

Double hits are allowed in HS on any first ball over. Multiple contacts are allowed in HS on hard driven spikes and blocks. The same is true in USAV and NAGWS volleyball.

It was a new rule change this year. 2 hits allowed on first hit only, because of a hard serve or spike. It is in the NFHS book, look inthe front under rule changes and it will direct you to the proper changes.