Can you provide information as to where you are located? These rates seem pretty low IMO, and you speak to location being an important variable, it would be helpful to know what region you're referencing.
I am in New England (USA). These rates are a reflection of what I've seen companies are willing to pay, not necessarily what I'll accept. For example, I have not found an effective way to get more than about $40/hr for Wordpress maintenance, so I have shifted to more backend and webapp work. Also, these rates are more of an average. Depending on the length, stability, and enjoyability of the project, I may be willing to work for more or less money.
Where do you find work?
Local tech meetups, friends, and family, and local tech meetups.