Drain in basement floor backs up
So, I have a very old home (over 100 years) and just recently the drain in the basement floor has begun to back up. The washing machine is the only thing draining into this line, from what I was told by the house inspector. I ran my 20' hand snake down into it and pulled up all manner of interesting things, but I can still see standing water in the pipe. What would be the best course of action in this situation? Call a plumber? Are there any chemicals that would help?
I will be doing my laundry at a friends for awhile, it seems. Any help with this problem would be greatly appreciated!