I live in a two story home. When we use upstairs shower and flush upstairs toilet the toilet downstairs overflows. Need help!! What would the problem be.
Thank you,
Lisa B.

Hey Lisa,
You have a blockage downstream from the downstairs toilet.
The solution would be to rent a sewer machine and snake the drain line.
This can be done a number of ways.
1) Pull the toilet and snake from there.
2)Snake from the roof vent that services the downstairs toilet.
3) If there's a stack with a cleanout you can snake from that.
Good luck, Tom