"sewer" Odor Mystery

EricTheHandyman

I have a customer that is complaining about a "sewer gas" odor in her home. She says that it does not occur all the time, only when the wind comes from a certain direction. She has had a pressure test done on the DWV system but claims that the guys doing the test were idiots. It is a townhome, with 4 homes stuck together. I notice that the vent stack coming through the roof in her home is 3" ABS, the other 3 are 2". She also states that when the wind is really blowing, she can see the water rippling in her toilets. Any ideas? Maybe it's not even plumbing related? Thanks.

Ron The Plumber

Tell her you will come by for a fee on the next really windy day.

CPlumb

Most likely ( in my experience ) She has a cracked toilet flange . They seldom leak gas but that seems to be the #1 repair in these incidents .

Check it out !

Double-A

A pressure test on DWV? Maybe when it was new and dry.

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EricTheHandyman

It seemed a little odd to me also. She said that the testers had water spraying everywhere when they did it and that the didn't go onto the roof to cap the vent, so my guess is that they were scamming her.

EricTheHandyman

I considered that, but she says that the odor is most noticable in the laundry room. My initial thought was that the water in the floor drain evaporates and lets the odor through. She says that there are also a couple of cleanouts in the room that I'll check, maybe one has a loose plug.

threaderman

Did anyone mention a smoke test? That is where I would start.Like Dbl.A says,no-way they tested the system with fixtures attached.

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AllAmerican

Eric,

Also, check the cleanout plugs for extra screw holes or being cross threaded. If either condition exists, pull the plugs and replace them with new. Replace the cover screws with new brass screws and apply some Teflon tape to the screws when you install them. Reset all of the toilets to make sure they are sealed.

You mentioned that the odor is most noticeable in the laundry room. Check the washer and dryer under frame for a dead rodent as well as the dryer vent duct. Not likely - but possible. Have the HO run the washer with hot water and bleach to make sure that eliminates stagnate water in the appliance.

If none of those things work, have the HO call you the next time she smells the odor and perform a smoke test on the system at that time. If the HO can keep from using any of the plumbing fixtures until you test, that may help you locate the problem.

Good luck. Sewer gas issues are tough sometimes.

Greg

EricTheHandyman

UPDATE

I went over to her house yesterday. Floor drain cleanout plug was stripped. There is a bathroom adjacent to the laundry room, and there was the tiniest of leaks at the wax seal. She promised that I'd be the first to know if the odor came back (there's some great news...). Thanks for the tips everybody!

kirbymurphy

How do you do a smoke test and can a confused, non-plumber like me do it? Is the peppermint test as effective?

I have the same problem as described above. Sewer gas on a random basis. May not have the odor for a month, and then have it 4 or 5 days in a row. It's not strong enough to localize, but very annoying.

Only in one bath. Installed new wax ring, but old one looked fine. Flange looks good. PVC and no cracks visible. Trap is never empty.

Sink in vanity has water in trap.

I might suspect the bath drain, but the house is on a slab so I have little access. This bath is never used since we use the shower in another bathroom. Is there a way to check the trap for water in the trap?

Help!

Bill

Smoke test to me makes the only sense as there are so many places for air to escape from.

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kirbymurphy

Here's a little more info. There are 2 bathrooms, back-to-back. The vent stack is about 5 foot away from where the drains are merging. The vent is between the waste drains and where the other drains should meet and go to the street. Make sence?

Just in my meager knowledge, it seems the vent should be almost adjacent to the drains. In this layout the drain has to travel 5 feet before it hits the vent.

I still suspect the bath drain is being siphoned out, so I've been running a bit of water into the tub after a flush. It "seems" to have stopped the odor, but like I mentioned before, it's random in occurence.

Whatcha think?

Pete M

Here's a good read on a simple smoke test and how to do it.
http://drainbiz.blogspot.com/2008/01...moke-test.html

Driftwood

Had an older cust. husband passed a couple of years earlier.
Sewer gas in bath. 2 nd vav. sink never used anymore. Dry trap! told Her to run a little water in it once a week. May not apply. But May help someone

kirbymurphy

Look what I found while prepping for a shower:




That's the DWV stack cut totally in half at the Tee where the sink drain enters. There is a folded sheet of paper I placed in just to show the cut. Apparently someone had a grudge against either the previous homeowner or the plumber and cut the T with a recip saw prior to drywall.

What a lousy place to have to replace it. The 2 vent pieces and the drain coming in are both rigid and there's a 2x6 stud where the 2" section is.

Guess I'll go buy a jug of JB Weld.

Do they make a Tee with rubber extensions that will allow me to cut above and below the old Tee? The bottom section is in a concrete slab and the top connected sold in the wall or attic.

Tinstaafl

Come on now, fess up. You did that yourself when sawzalling the drywall.

Minor PITA, but based on that pic, it shouldn't be too hard to repair. just cut all three pipes back far enough for a junction and a short straight piece on each, coming into a new T.

Remodelers deal with tougher stuff than that on a regular basis.

kirbymurphy

Who me? Never! Well not this time anyway. My recipro is a short-blade battery unit and wouldn't reach that far anyway. I figure the owner or builder or the plumber pissed someone off and that person exacted his revenge. I think it's 20 years old since there is no sign of improvements anywhere in the bathrooms.

That smell has annoyed me for 2 1/2 years and finally I found it.
Sewer company did an inadvertant smoke test for me a month ago when they checked their lines. Smoke filled the bathrooms but I saw none from the drains. The break is in the wall between the bathrooms.

Me fix that? "Maybe", but It would take me forever and look like crap. I'm having a plumber prep the old tub area for a shower so I guess I'll have him do it. I'm just happy to have found it!

stp57

My sister had the same problem. The smell was even outside her house. The neighbors thought that she wasn't cleaning up after her dogs.
It turned out to be a wet bar sink in a closet that hadn't been used in ages & all of the water in the P-trap had dried up. It's been a couple of years now & no smell.
Steve