I got around to changing out the rod in my unit yesterday, it looked like brand new so now I have a spare, good more spare parts! Usually, after a year, they get pretty eaten up. I have never winterized or drained the system and always keep the unit full in storage, as before, it is our earthquake kit. The only reason I can think of is that I have used a cheapy filter to fill the tank or hook up to park water. The tank had the usual amount of sediment and I will break down and get the wand at CW to rinse it easier, it would make it about a 15 min job...........................