So we bought this house 2 months ago. It was built around 1930, and is located in Fort Thomas Kentucky. Up until about 2 weeks ago there seemed to be no plumbing issues other than a slow shower drain on the second floor. The only thing that changed was that my wife cleaned a few paint brushes in the utility sink in the basement, so I'm not sure if that could be the factor that started everything. The wash machine dumps into the utility sink, the utility sink has about 3' of pipe that goes directly into the plumbing stack. Starting last week, every time we flushed a toilet, ran a shower, or whatever, 1 of the 4 basement floor drains would make a gurgling/gulping sound. Then one day after running the wash machine, water came up through that floor drain and made a puddle around the drain. Then the next time the water came up from two of the 4 drains and made a much larger puddle around each drain and got a lot of our stuff wet. I rented a 50' auger with a 3 or 4 inch head and went in through the stack. the snake went all 50' without any resistance but it did bring back a few tiny black roots. I tried to put that same auger through the floor drains but the angle was too sharp and it wouldn’t go. I then ran the wash and it instantly backed up again and was no better. While at work the next day, my wife ran the dish washer and i came home to find water all over the basement floor. 3 of the 4 drains backed up, but this time there was a lot of mud and what looked like decomposed leaves all caked around the drains. I cleaned all that up and ran a small 25’ snake for 2” pipes down each drain and did feel some resistance that was broken up by the snake, but even after that, as soon as I turn on the water in the utility sink (same sink the wash machine dumps out into), the drains start filling with water and start to overflow. Not sure how the problem could be in the house if the utility sink goes directly into the stack and I've snaked the access point in the stack... The only thing I can think of is that there is a block farther out (maybe 60-70') and its full of water all the way back to the house. The 50' foot snake only snaked through standing water, and it only takes a little extra water to top it off and cause it to spill into the basement. Q's: Does that sound accurate or am I missing another obvious possibility? Any chance it's a venting issue? Do you think I should have just rented a 100’ auger the first time and that would be the best solution, or is it time to just break down and call a professional? If it does appear to be a root issue in the sewer lateral, would there be any benefit in using the foaming root killer that you can flush down the toilet? And if so, should I go back in with a 100' auger first? Is there any risks to the plumbing when using the foaming root killer that I should be aware of?