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Marty, professional remodeler
Category: Home Improvement
Satisfied Customers: 122
Experience:  30 years of home remodeling
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Odor from shower drain

Customer Question

I have a real problem with what smells like sewer gas coming from a shower drain. The only time the smell comes through is when the shower is in use. This suggests the water seal in the trap is doing it's job. Even when the shower is running, there is no smell until a foaming soap product is used - either body wash or shampoo. When bar soap that does not produce substantial foam is used, the smell is not there. This is an 18 month old house and the problem started 9 months after moving in. I originally suspected a blocked vent pipe, but the plumbing company sent by the home warranty folks ran a camera through the system and found no blockage. They claimed that it is bacteria build-up and suggested chlorine bleah and water treatments. I've poured countless amount of clorox and other plumbing cleaning chemicals down this drain for about 9 months now and the problem still persists. I have a hard time believing at this point that the problem is bacterial. I swear the odor is clasic sewer gas. I have searched a few web sites for information what I've read suggests that there may be a cracked vent pipe or some other mechanical plumbing problem. The fact that it only happens when there is a foaming agent running through hte pipes is a real head scratcher.
I am at a loss to figure out what to do next. I'm certain I can get this taken care of under the original home warranty, but I'd like to be armed with more understanding of what the problem really is before I re-open the case.
Does any of this make sense? What advice or insight can you provide? Thanks.
Submitted: 11 years ago.
Category: Home Improvement
Expert:  Steve -- a.k.a. Oreport replied 11 years ago.
I would enlist the help of the local office of your state Environmental
Protection or Health Department or your City Safety Code enforcement
folks in confirming/documenting this problem and helping to bring about
a remedy under your home warranty.

If necessary, I would involve the local media (have them do a story on your plot) to ramp up the pressure to get resolution.

You can also get your State Attorney General's Consumer Affairs Office involved.

In short, make it easier for your problem to be fixed than ignored.

Good Luck!


Expert:  Marty replied 11 years ago.

Is it only the SHOWER drain ??

Are the vanity drains O-K?? How about the kitchen sink( as this gets "foamy" water too)

If you have a "WET VENT"( a drain line that acts as both vent and
drain), which is unlikely in an 18 month old house (but I'm not sure
what the codes are in your area) the foam could block / redirect the
escaping sewer gas


Customer: replied 11 years ago.
Reply to Marty's Post: It's only the one shower drain. It's in the ground floor and the house is built on a slab - tough to get to the trap.
Expert:  Marty replied 11 years ago.
Do you have any GAS appliances?(water heater,furnace,stove etc?) The
smell of natural gas and sewer gas are similar(sulfur is added to
natural gas to detedct its presence.) Being on the ground floor and
natural gas is heavier than air it is possible this is a gas leak. The
shower may have nothing to do with it .I know you said it's O-K the
rest of the time, but sometimes, we come up with our own conclusions to
a problem that lies elsewhere.

Have the gas line checked with a "sniffer", an electronic device that
detects the presence of gas. It can 'pin-point' the exact location.
Either your local utility company or the builders' plumber should be
able to do this for you.The utility company would probably be quicker.
You can check the connections youself with a soapy water solution or a
commercially available leak detector, but the sniffer is more reliable.

The only other possibility I can think of is an open or improper vent
line. Do you have a waste pump for your laundry sink or washer? If the
seals were bad on the pump, it would let sewer gas escape. If the
laundry sink or washing machine trap went 'dry' by non-use this also
could allow gas to escape. An improperly installed airconitioner
condensate drain could also be a cause(it, too, should have a trap or

Hope this puts you on the "right path"!!


Expert:  Marty replied 11 years ago.

Any luck yet ??

Would like to hear what you've found out !!