I just bought an older house and some of the pipes were replaced some were not and honestly I have no idea where the septic tank is located or anything about it. I have been living in the house for 6 months and the shower has always been a slow drain but the other day it took 15 min just for a small amount of water to drain. At the same time I noticed the toilet water bubbling in the bowl and eventually it too drained out. I went and got some stuff for drains/septic tanks and the next day the toilet worked fine and the bowl filled everything. That is until I got a shower again. Same problem took shower forever to drain and toilet bubbled then drained. It seems to only happen when I take a shower?? Any suggestions