Detroit sewer lateral problem suggestion
I am Dr. Werner a real estate investor and jack of all trades in rehabing homes. I could use an opinion concerning the following problem from anyone that would be kind enough to answer.
The problem started about a month ago in my Moms basement. The sewer lateral started backing up raw sewerage in Moms basement after much heavy rains here in Detroit, Michigan. The sewers are very old in the alley nearly 80+ years. I have a KV375 1/2" drain machine with a 3" cutter attachment on the end. (We also have cast iron drain pipe all the way to the alley main) I snaked the main line all 75' with no problem at all as it came back clean each time I did it. I snaked it 10 times just to be sure! LOL The line still holds water with no movement of the sewerage at all. I called the Detroit water and swerage board and they opened the manhole and ran a vactor down the alley sewer and claimed it was not their problem but mine. Now the interesting thing is that the manhole on the next alley from me runs literally like a stream! The movement behind my Moms house is really a small trickle compared to the other line as seen from the open manhold that I opened and looked down at.
I then rented a 3/4" 100' snake just to be sure and it ran two times out fully (all 100 feet) and came back with nothing! In fact the rental place told me that 65' lots like we have is shorter than the snake length and to be careful not to enter the main sewer and hook the lite line that was in there for camera work.
So at this point being an experienced repairer, I would like to gather some suggestions as to what could be wrong as nothing seems to be either's problem (the city or mine)! I was thinking since there are so many empty and abandoned homes on the street of my Moms home perhaps the sewer in the alley really needs to be jet cleaned more carefully.
What is normal flow for the sewer as seen from the manhole? And can a sewer lateral line from the house to the alley be clear and yet hold water?
You know the old saying "it's not the citys problem" most of the time!
Appreciate your valuable time