Every time the washing machine drains, backwash comes up in the sink and the bathtub. WE thought it was because we didn't have the plumbing vented. We added vents yesterday and the washing machine still causes backwash to come up in the sink and the bathtub. There is also a terrible smell coming from the bathroom when this happens. Any suggestions?

If the commode does not bubble or if the water in the commode does not rise, you main sewer is probably not stopped up. But the line from the washer, that is connected to the ssink and the bathtub is Partially stopped up and as the washer pumps water out of the tub it goes out faster than it can run out the drain. That causes the water to rise in the sink and tub. The rising water also pushes foul air into the bathroom through the trap under the tub shich causes the bad smell.

Not knowing exactly how your plumbing it laid out I am going to say to get a 25 foot cable in a spin top, ( you can get them at Home Depot). Now the best place to use it is down through the vent of the bath tub, if this is not possible take the face plate off the over flow on the tub and ente there with the cable.

Let me know how this works.