HeyBub wrote:
Stormin Mormon wrote:
Friend of mine, is acting as caretaker for a family member's
house. The power got shut off, and the house is cold inside.
Down to 37, last he checked. Four burneers on the stove for
an hour raises the temp two entire degrees.

Last night, we put RV antifreeze in the drain traps.
Toilets, sinks, showers. We considered the dishwasher. But
that hadn't run in six month or so, and probably the trap
dried out. Washing machine is in the cellar, and should stay
warmer.

For $3.97 that might be a lot cheaper than replacing a bunch
of broken pipes. I got to thinking. On the way home, I
bought myself a jug of antifreeze. Might never need it. But
it might be cheaper than replacing a bunch of pipes and such
if I need it here, or for a friend some day.

I don't understand. How can freezing of water in a p-trap present a
significant problem?

Water will still be in the supply lines, probably even if it is drained, and
can freeze. If the water was not shut off the house could be flooded when
the supply pipe splits.