I've got sewer gas in a bathroom my new construction, source unclear. No dry
traps, replaced (and doubled) the wax seals, checked the roof vent, no obvious
liquid leak anywhere. Smell present for months-- this isn't a dead animal. I
suspect I have a hole somewhere in a vent pipe, probably due to an electrician
drill bit. Sheet rock is up, complicating the situation. I did a Google
search, and several people have recommended capping the roof vent and the
septic, and placing a "smoke bomb" in a clean out. Smoke will fill the system
and presumably leak out the hole, wherever it is. The local plumbing supply
houses haven't heard of this technique, and don't sell "smoke bombs". One of
them raises the reasonable concern that a burning "smoke bomb" could damage the
Has anyone heard of this technique, is it reasonable, where are "smoke bombs"
available, are there other techniques available that would be more reasonable?
Here are some sources:
You'd have to build some sort of smoke generator with blower to push
But if the leak is in a wall stud space, how will you see the smoke?
Drill small holes in the drywall maybe?
You can also pour a few drops of Wintergreen oil down the vent
and sniff around for the odor.
Or a small qty of a volatile hydrocarbon and use a gas leak
detector (they're very sensitive) to localize the leak.
Cap off both ends and introduce (low) air pressure and listen
for escaping air.
Smoke bomb,,, fire and methane gas. Ok it is your house. Better make sure
your insurance will cover the mistake.
I would try borrowing a sniffer. We use them at work for testing confined
spaces. Seem like an non invasive method would be better than fire in the
You might try getting a CO2 tank and blocking the vents and pumping CO2
into the vent and trying to find the leak with a CO2 detector which are less
expensive than my attached link.
yes, hire a guy with a camera to go into the vent pipe and look for the
hole that you think you have.. after he goes in there and does not find
a hole then you can eliminate that thought... cost me about $200 to have
them check for a leak in under slab drain line about 5 yrs. ago......
You're being given wrong info. I got a couple of smoke bombs for about 3
dollars each from the local plumbing supply house. I was needing to smoke
test my sewer line. Better to have a second bomb in case the first one
Anyway, I cut holes in the sides and bottom of a can that exactly fit into
the test "T", and adapted the top of the can to fit the vacuum cleaner
nozzle. That way, there was no exposure of the bomb to the plastic, since
PVC doesn't take heat very well.
Before you get started, though, sniff around near the base of the commode.
If you have tile, and things are not just so, you may well have the leak
there. Probably no water leak, but quite possibly a gas leak path.
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