Do you have a basement floor drain? It would be deeper than that in your sewer line. My favorite sewer camera inspection ($150)/sewer repair expert is Shon Moore, cell phone: 608-9652. My favorite drain and sewer cleaning ($100) expert is Gary Brown 887-8000. Either of them can tell you what you have and advise you on decisions about whatever you might have or need.
After 4 drought years and now a wet year, sewers all over town have moved and broken. An inspection is a bargain compared to the mess a bad sewer can make for you.