I noticed that you have posted this problem twice with no response. I don't think anyone is trying to ignore you. Pipe noise problems have so many possibilities, it is very difficult to diagnose "on-line". If it is really a serious problem, I would complain persistently to the property owners until they bring out a plumber to look into it.

Sorry I couldn't be more helpful...

- John Scates

: Hello- I live in a condo/apartment and I share a wall with some neighbors. Every time they run their shower (or flush a toilet sometimes)I hear this knocking sound that seem to be coming from my toilet. I also hear it every morning at around 6:15 to 6:45. It isnt consistent- it varies in volume and pattern (it gets pretty loud sometimes and wakes me up). I was wondering if it was air pockets in the drainage pipe or something else. Thank You