Every time I wash a load of clothes my rinse water backs up in the tub and toilet

Hi ET

You have what we call a "partially clogged drain line". Here, you don't notice the partial clog until you use a fixture with a large volume of water, i.e. the washing machine, and then the drain line becomes flooded and backs up into the tub and affects the toilet drain as well.

If you are on a slab house or these fixtures are in the basement (or lowest fixtures in the home) and this is happening then I suspect that the main drain line is clogged and the drain line will need to be snaked with a large electric drain machine. If you are on septic, the tank may need to be pumped clean... maybe(?).

Mark

Great explanation by Massplumber. This can be addressed by several ways. You can pull the toilet and snake from there or you can snake from the washer roof vent. If you snake from the roof vent, put out enough cable to reach the base and 15' more.
If you'r on a septic tank. You can check it by opening up the house clean out and cycling the washer. If the septic tank needs pumping water will back up out of the cleanout. Good luck, Tom