Kitchen sink, toilet, and bathroom sink backed up into tub
For a few weeks now because we really can't afford the plumber at the moment. We have been using the other bathroom and it was fine. None of the water used in it backed up into the affected bathroom. We tried plunging tub and toilet, both at the same time while plugging up vanity sink drain and the overflow. It didn't work, and this black colored water continued to stand. We had to bail it out once. We stopped running water in the kitchen sink, because it would all drain into the tub. I bought a snake for the toilet, and this didn't unclog anything. Prior to the backing up, a sock had been flushed.
Today my husband uses the 25ft snake through the roof vent, which is above the affected bathroom. He pushed in all but the last 7ft, and met resistance. After he pushed that through, he heard swooshing and gurgling. The rest of the snake almost got away from him. Meanwhile, I'm in the functioning bathroom, and the dirty black water is backing up into that shower! I ran to the affected bathroom, and this water from the tub and toilet drained...but now the other bathroom is backed up. So he goes to this vent stack too and snakes it. No improvement, and now both bathrooms are out of commission.
Is the next step to snake the main line? We haven't found it yet, and it's buried. We have to do more digging, and we have a metal detector. The neighbor's, we checked the proximity of where theirs is located,so we have some idea.
What could be the trouble? When this clog moved and the other bathroom became disabled, that was the last thing we were expecting!