On 3/24/2017 6:04 PM, Wayne Boatwright wrote:
On Fri 24 Mar 2017 02:54:17p, dpb told us...

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.

--



We have a number of plumbing fixtures that are seldom used, so we
routinely flush those toilets and run water in the tubs and sinks to
make sure the traps don't run dry. We're not on a septic system, but
all traps, regardless, can potentially run dry if not used.

Yep, that's the first thing to check. Find every drain and dump a small
bucket of water down it. If any of the traps are dried out, the
plumbing stack vent will not have any effect on the situation he
describes. It really doesn't take all that long for a trap to dry out if
it's not constantly doing its job.