I drain mine and leave it in... There should plenty of room inside the HW tank for expansion from any small amount amount of left over water in it.
I am planning on installing a 120VAC low wattage Electric heater core in this spot pretty soon when I start playing with my Hydronic Heating System changes so this may change my winterizing methods. My hot water heater is presently propane gas only...
Roy and Carolyn
I claim Horse Creek Country in Southern Ill - Momabear is from North Texas
We live in King George VA
RETIRED DOD DOAF DON CONTRACTOR Electronics Tech 42YRS
"We're burning daylight" - John Wayne
2008 STARCRAFT 14RT OFF-ROAD POPUP with PD9260C and three 85AH 12VDC batteries
2010 F150 FX4 5.4 GAS with 3.73 gears - Super Cab - Towing Package - 2KW Honda EU2000i Gen
K9PHT (since 1957) 146.52Mhz
"We always have a PLAN B"