Water left in lines to freeze can cause extensive and expensive repairs and winterizing is a simple undertaking. This annual task is a good time to check systems and take one last look before buttoning up for the winter.  Regardless of whether you choose to do this job yourself or have an RV service center do this, it still must be done annually in most parts of North America.

There are 2 basic approaches to winterizing. The first involves removing water from the system using gravity to drain or using air to blow out systems and then filling traps and low points with antifreeze to prevent any remaining water from freezing. The second method assumes that you cannot empty lines and so are going to replace standing water with antifreeze.  Most Airstream owners opt for the first method explained below. Be sure to check your owners manual as system designs and appliance specs differ from model to model.
 
Begin by taking a trip to the dump station and emptying and flushing  your waste tanks.
Once parked for the season, level your Airstream and ensure that your hot water heater and water pump are off.

Many Airstreams have a low drain point valve that is below everything else.

• Drain and flush your fresh water tank and hot water tank.
• Open the hot and cold taps and uncap/open the low point drain line/s.
  
• Once empty, recap or close valve and close taps.
  
• Some owners choose to leave the low point drains and taps open to allow condensation to evaporate, but be aware that doing so may allow bugs and dirt to enter lines.
  

If you do not have low point drains you will need to blow out your lines using compressed air or replace all water with antifreeze (see owners manual).

• Attach compressor adapter to the city water inlet and make sure that pressure stays around or below 60 psi.
• Open each tap sequentially and allow water to drain, don’t forget the sprayers and showers.
• Hold open the flusher on your toilet to allow valve to drain.
• Drain any water filter canisters you may have and reinstall empty canister- add new filters in the spring.
• Any appliance that holds water will also need to be drained - consult your manual for instructions (washing machine, dishwasher, ice maker, etc).
• Open your hot water drain plug and let it empty. Some water will remain in the tank until spring when it’s flushed, but as there is expansion room in the tank, it should do no harm.
• Replace all drain plugs and close taps.
  

Add antifreeze:  Purchase antifreeze labeled for RV’s as non-toxic only!  Anti freeze comes unflavored or in flavors. As it may leave a residual taste in lines even with thorough flushing, choose unflavored or a flavor like. The mint flavor lingers a loooong time.  Add a cup of antifreeze to each drain trap and to the toilet (do not flush)!

In the spring you will need to flush your system and sanitize your fresh water system for the season.

• Hook up city water and close the low point drain, leaving taps and water heater plug open. Thoroughly flush system for several minutes.
  
• Turn off city water and put drain plug back into hot water heater and flush again.
  
• Close taps and check for water leaks.
• Treat your fresh water tank to sanitize using commercially available products or a diluted bleach solution (1/4 cup household bleach for 15 gals of tank capacity), draining via trailer taps, repeating and draining until water is odorless and tasteless.
  
• Flush system one final time and then install an new filter cartridge. Refill water tanks and go camping.