“Don’t assume that every Mr. Fix-it advertising his services in the local Pennysaver or on Craigslist is a licensed plumber,” says one New York plumber. There is no national standard for issuing licenses. Some plumbers are licensed by the state, others by the counties they work in. Check with your local city hall or chamber of commerce. They should be able to direct you to the appropriate source for a list of licensed plumbers in your area.
Let's start with the easiest possible project: Installing a new shower head is as simple as it gets. Typically, all you have to do is unscrew the old shower head from the shower arm (the pipe coming out of the wall), clean off the threads on the shower arm and wrap a bit of Teflon tape around it, then screw on the new shower head. It's really that simple (and if you don't believe me, check out the video above from Dummies.com). Do read the installation instructions on the shower head you buy, though. Some are designed not to require Teflon tape and can actually leak if you use it.
Alejandro is the best, most versatile plumber I have ever used. When I needed a new toilet installed in a guest bedroom, he also did a great job replacing the the damaged tile work around the base of the old toilet. When I had new countertops installed in my kitchen, he came up with a creative solution to a problem I had with the old gas line running to my stove-top. He is not expensive, a nice guy and a true professional. Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license