My mom is a janitor and has been for several years at a school cleaning up after others.
an unsung hero job
Absolutely, my mom often came home covered in dirt and she always took a shower first thing!  She always talked about the unpleasant things she had to do.
sounds like a tough job but also can be rewarding
The average pay in 2010 was about 10.68 an hour and my mom made about  15 an hour which is good pay for sure.  
not bad but still underpaid for the amount of work you have to do
True, its not very much but statics show in 2010 that salaries should go up 11 percent per year which is more than most other industries.
so it increases more than average  that is interesting, i would thought it would be more stagnant