each year,era, model and size may be different.
most models have ducting from the furnace to at least SOME of the tanks...
and most plumbing is INSIDE the living cavity.
keep the inside warm and the pipes survive.
NONE of the external plumbing is insulated or heated.
drain, freshwater inlet, exterior shower and so on.
so in freezing temps it is best to FILL the fresh tank for use...
then disconnect all outside hoses
and stay warm inside with the furnace rather than space heaters...
(some smaller units might be ok with space heaters if WARM enough.
then use the hoses only as need to REfill fresh or drain holding tanks.
NOT ALL MODELS have ducted heating 2 the tanks.
for example your 23 doesn't.
it does have a 12v
heating element 4 each tank.
this is described in the owners manual as follows...
The furnace on Safari models except for the 22 ft. and 23 ft, models is ducted to provide heat to tanks and plumbing to prevent freezing.
The 22 ft. and 23 ft. models has 12-Volt heat pads installed with the fresh, gray, and black water tanks.
These pads are individually switched. This feature allows the saving of battery power in a dry camping situation.
To conserve battery power, RV antifreeze may be used to protect the gray and black tank.
Battery power will last about 3 hours using all three heat pads.