Hi, in our 1910 house, it seems the toilet waste is backing up into the washing machine drainage sink. The machine is in the basement and the two toilets are on the upper floor. one on the first, one on the second, no new construction has happened. The machine does not back up on its own. It has happened twice in the past three weeks. Any help on what could be happening? Thanks so much

Sounds like you have a partial blockage downstream from the washer. Snake the drain line from the sinks roof vent. If you have "S" traps then send the snake down into the drain through the open trap. Good luck, Tom

Indeed, you need to call plumber to snake your drains.

Thanks, calling the plumber now.

Just a follow up, called the plumber, he snaked it and there was a small tree root growing in the pipe. Old pipes approx. 1910, but the snaking should hold off the replacements of pipes. Thanks for your help!

just a follow up, called the plumber, he snaked it and there was a small tree root growing in the pipe. Old pipes approx. 1910, but the snaking should hold off the replacements of pipes. thx for your help!
Hey Ginger, Thanks for the update. Here's a little something that will help with the roots. For immediate relief and to kill the existing roots and prevent further growth you can purchase RootX or Robics Foaming Root Killer that contain Dichlobrnic.
A less expensive way would be to call around to garden supply stores and ask for fine grain Copper Sulphate. Put a 1/2 pound in your toilet and flush it down. Repeat in 6 months.
Let me say that sooner or later you're going to have to bite the bullet and replace that old sewer line with PVC.
Hope this helps and thank you for rating my reply. Tom