Re: The Oddest Plumbing Problem
Based on some information you provided I wouldn't go with a vent issue first thing.
Originally Posted by TRice
If the vent was restricted enough to affect the toilet when flushed --- then likely you would hear gurgling from the sink or tub/shower trap as air would be drawn in from either or both of those drains --- also the water seal from those traps would be sucked dry.
As well, a restricted vent would affect the the draining of the sink and tub/shower not only the toilet.
The foul water may be a result of the 3 inch toilet line actually being sloped back instead of away and depends on how and where the sink and shower drain connects to the 3 inch line. If the 3 inch slopes back, crap will accumulate in a low spot and eventually could work it's way back up into the toilet --- add a partial blockage would make matters worse.
As for the *noise* I haven't heard anything like you describe coming from a drain system. Usually if this noise only happens at this one toilet then I would look at an issue with the fill valve diaphram inside the toilet tank being faulty or the shutoff not fully open.
2 cents woth.
"" an ounce of perception -- a pound of obscure "