One of our outdoor drains seems to be clogged, so I called a plumber to see if they would look at it. He asked me where the drain goes, and I have no idea, all I know is I don't see it emptying anywhere else on the property. He said I need to get a sewer company to look at this.

I may sound dumb, but what is a sewer company? And does anyone have recommendations?

TIA!