Take home online classes about plumbing from an accredited college such as Penn Foster Career School or Ashworth College. These courses show you about pipe assembly, water heating systems and water-based appliances such as refrigerators and dishwashers. A Plumber Career Diploma should take no more than two years.
Read books about plumbing to improve your knowledge. This is especially helpful if you choose not to take online plumbing courses. Look for books that feature color pictures and graphs that point out the different tools, pipes, parts and assemblies you'll be working with.
Visit how-to websites to learn different techniques. Look for videos on plumbing subjects that are hard to learn from words or pictures, including how to solder pipe, how to install a sump pump or how to join PVC piping. These websites are especially helpful when you have a specific question or concern that a general book on plumbing can't answer.
Gain instruction from people you know that are good at plumbing. Much like serving an apprenticeship, you can learn various plumbing techniques from experienced friends and family members. Write down a list of questions or concerns you have and bring these concepts up to your friend. It's often easier to see how a ballcock assembly is removed from a toilet in person than reading a description in a book.
Perform plumbing tasks at home to gain a thorough understanding of the topic. A 2009 study by Purdue University found that students learn technical subjects better when they take a hands-on approach. Perform simple home plumbing repairs when needed. If a pipe is leaking under the kitchen sink, tackle this repair yourself to test your knowledge. The more you practice, the better you'll become.