On 03/24/2017 3:02 PM, Bob wrote:
....

When a large amount of water is flushed down the pipes (i.e. bathtub
emptying) the basement fills with sewer gas. Found a clean-out cover
rusted out (and now fixed) but still having the gas odor.

I think that when the waste water enters the tank, the gas gets pushed
back. ...

Can't unless there's a line w/o a trap or a trap of a long-deserted or
unused trap is empty; if the house has been unlived-in for a while it's
quite possible some have evaporated enough to leave a path if not
everything is being used.

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