A lot of these folks have motor homes - in fact they live in them. The Snowbirds don't have to worry about winterizing their coach because it's never going to sit in the freezing cold during the winter months. That's not true for many other motor home owners though.
If you live in a cold climate you need to properly winterize your coach to avoid having your plumbing explode in the cold. Nothing is going to ruin your cheery spring mood like have to spend thousands of dollars repairing your pipes before you take your first road trip next summer. Here's the recommended process for protecting your motor home plumbing.
1. Drain the water from the plumbing system and fill the plumbing with potable antifreeze.
On the undercarriage of your rig you'll find a low-point valve. You need to open it; this is where all the fresh water that could freeze and destroy your pipes will drain. It's going to be a little tough to get to.
After that valve is open, get into your coach and open all the sink and shower valves and flush the toilet (you don't want a frozen exploding throne do you?). Turn on all sink and shower faucets so those can drain too.
2. Install an anti-freeze installation kit.
All you have to do is insert the valve after you detach the inlet line from the water pressure pump. Any installation kit you buy should come with a graphic showing you the process.
You'll want to point the valve handle toward the transparent hose that comes with the kit, and you'll want to put that hose in a jug of potable anti-freeze. That takes care of getting anti-freeze into all your plumbing. Remember - you want potable anti-freeze (not the stuff for your car)!
3. Install a water-heater bypass set, which is a series of valves that keep the antifreeze from going into your water heater. This part may be a little complicated. You only have to do it once, so I recommend taking it to your local motor home mechanic and having him do it.
4. Drain any water out of the water heater; if any is left in there, it will freeze and burst the heater. That's another expensive repair!
You'll need to open the drain petcock on the heater, but you'll have to be firm because finger-operated valves have a tendency to get stuck after being heated and cooled off several times.
Open the relief valve on the heater so air can get in and push the water you're trying to drain out. Otherwise this one part of the process could take hours. Just don't forget to close the petcock and the valve after you're done draining the water heater. Those are little details you don't want to remember next spring when you're de-winterizing your motor home.
5. Now that you have your anti-freeze installation kit ready, get in the coach and turn on each sink and shower individually (both the cold and hot faucets) and run them until you're not seeing any more water, just the potable anti-freeze. Do the same thing with your shower and the shower wand so you know there isn't any fresh water left to burst your pipes or other plumbing fixtures.
You also want to let enough anti-freeze run so your sink traps and drains get covered with the anti-freeze. One final note: if you have a water filtration system make sure you disconnect it before running anti-freeze through the whole system. It will make your filters unusable.