Sewer smell

[Ray-IN]

As Kirk said, the air admittance valves under the sinks can fail, the "P" traps for washer/dryer and shower can empty and allow tank odors to enter the living area. As jackiemac said the gray tank can smell just as bad as black tank.
Your incoming fresh water has nothing to do with the odors. edit: Well, unless your fresh water smells in the beginning.

 

[Gary RV_Wizard]

These "old wive's tales" may have had some relevance at a time in the past but live on well past any previous usefullness. 5 or 10 lbs of ice sloshing around in the typical 20-30 gallon tank of a bygone era may have helped at times. As did "burping" an RV fridge back in the 70's or 80's when the absorption cooling units were cruder in design. Both measures were mostly a last resort measure anyway.

 

[Mark_K5LXP]

Sounds plausible, some "rocks" bumping around in there while driving and knocking the "chunks" loose. There's a number of utoob videos about this that don't support the theory.

Mark B.
Albuquerque, NM

 

[zulu]

A couple of cups of bleach . . . smell be gone.