Unpleasant smell coming from the main water pipe?....?
There used to be a meth house across the street. Every time the drain had "an odor" there would be a bunch or cars prked there for days and odd people wandering around the neighbor hood.
If the smell is coming from the tap, the municipal water source is being "fortified" with things to combat whatever they dumped in last time.
Well, that's the way it is around here, much like our neighbors' family having their yearly weekend-long loud drunken Easter that draws flies in like mad! You may want to call a plumber. I've heard that Simple Green D works on sewer smell; if you can find it, try it and let us know how it works and where you got it.
"Aw! Why does everything that only happens to stupid people happens to me?" - Homer J. Simpson