There are a few reasons that the majority of paid domestic workers located in Los Angeles come from Central America. One of the reasons is that Central American Immigrants are located closer in LA in american immigrant neighborhoods next to groups of middle class people, while other immigrants (mainly mexicans and such) live in different areas to the south and east of LA.
Another reason is that other immigrants now have a community set up in the United States (for example mexicans) that mutually assist each other of the same race, in getting jobs in different sectors like industry or information systems. This is because they have been immigrating longer and will generally have family for friend in the US that can help them. Central