When I do laundry the smell of our septic tank comes in the house. Any ideas about what can solve this??

Chances are good that your washer drains into a stand pipe that has not trap. Try capping the stand pipe for a few days to see if the smell disappears. There may also be soap and lint rotting in the pipe. Mix 1/2 cup of salt with 1/2 cup of baking soda. Dump into the stand pipe and then add a cup of vinegar. Flush tomorrow with hot water.