Comment: Re:I think that's all college students (Score 1) 823
Agreed. Those that are self employed make between 80-200 per hour.
It's not difficult knowledge to obtain, it really just takes time to get licensed and understanding of basic rules and reasons why things are the way they are (mostly dealing with gravity, angles, how liquids flow, how many turns you need to have on a run of a pipe, etc).
There's some math required in calculating throughput (water flow/outflow) - which resembles network design or memory optimizations.
There's a lot of parallels between the two.
What sucks about the plumbing jobs is that you often have to go to questionable locales and houses and deal with other people shit. Literally.
No one calls a plumber when things are well (with exception of new construction jobs), so you get to charge a premium for it.