Winterizing your trailer is one of the most important service work you can do on your trailer. When it's done wrong, it can cost you thousands of dollars. Make sure you take it to a reputable dealer or Mobile Service Technician to be done right. There are many steps in the winterizing process if missed, can be costly. One of the main steps is making sure your Hot Water Tank is drained and turned to bypass so you are not filling up the tank with gallons of Anti-freeze. If you have a residential toilet on a seasonal site plumbed into septic or sewer system, you need to make sure you fill up the tank with anti-freeze as well. Washers will also need to be winterized. If you have a water filtration system, you'll need to take special care to make sure it's been properly winterized. If you don't have a good step by step system on how to winterize your trailer, I suggest you take it to your local and reputable dealer to have it done properly so you aren't paying for your mistakes. Most reputable dealers don't make money on winterizing as a way to retain or gain customers. So it's probably the best if you are in doubt how to winterize your trailer, take it in to your dealer or trusted Mobile Service Technician.