I have done my own freeze test.
Back on 2006 I took the north route to Utah and NV Well when I stopped for the night in Wyoming the weatherman said "low tonight 19" I figured we'd be ok.
Woke up long about 3am, feeling a bit chilly, -6 on the outside temp display.
Busted a fitting less than 10 bucks to repair. (ICE MAKER line was full of air by the way).
Last winter hit 11 degrees, Could not flush toilet, (Pex froze) Connections were well heated but the line that crossed over from the water pump (Curb side) to Toilet (Driver's side) froze. And thawed.
NOTE: only the cold line froze so I flushed with a 2-quart measuring cup as a bucket and dumped hot water in the thing to flush it. (You can do that with a Sea-Land style).
Soon as the temps came up with the sun flow returned.. No damage, repair cost 0.00.