We full time and are going to be leaving the RV for a week for a vacation. It is in the Carolinas and the temps have been around 40 during the day and mid 20s at night. Propane has been lasting 4-5 days max before we have to switch tanks (30lb). We do have tank heaters, and it is 2021 solitude with the insulating layer underneath, but it is not skirted in the location we are right now. With this, and a heated water hose we have had no issues whatsoever, but it is forecasted to get slightly colder this coming week (low of 19).
Things we have read say that pipes can burst and you should winterize, etc.... but how can the pipes burst if we turn the water off and all tanks are drained? Also, how do you “winterize” if you are living in the RV full time? Any help is appreciated.
As you learned, there can still be water in sections of the plumbing, that could cause problems when it freezes. Expanding ice inside things (like a water pump) can crack fittings/housings/etc. In main lines, expanding ice with no outlet can compress the air in the lines to such an extent that they burst.
Safest is to drain everything, then winterize with antifreeze. It is quick to do, cheap, and doesn't take all that much (2-3 gal). You do not need to add any to any of the tanks, just drain them (Empty tanks have lots of room for water to expand in to!). Just get it in all the plumbing - low point drains, toilet line, laundry (if equipped), outside showers, etc. Read how to bypass your water heater - it just needs to be drained, and does not need antifreeze. Pour a cup or two into each of the waste drains (sinks, shower, laundry). Leave all drains/taps open.
On your return, reconnect and put some water in you water tank, run the pump, and flush all the lines. Since you're only flushing out a couple of gallons, it won't take much water. RV Antifreeze is safe to put down the sewer line. It is non-toxic, so while you want to get it out, any tiny bit missed will do no harm. Reset the by-pass on the water heater and fill it up.
Sanitizing is always good to do, but
not needed for getting the antifreeze out. The first time you do this, it may take 45 min. for you to winterize as you learn. 15 min. to get back to normal on your return. The next time, you will be twice as fast. Will cost about $15 or less, cheaper than running heat while you are gone, which you won't need to run at all.
Many use compressed air to blow out the lines, which works too - but it takes the same amount of time, and you need a compressor with a decent amount of capacity (no 12v tire inflator). For just once-in-a-while, antifreeze is the way to go. You'll be surprised at how "not a big deal" it ends up being.
