Basement sewage smell


  #1  
Old 06-14-20, 07:01 AM
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Basement sewage smell

Not sure where to post this.

my family has complained a few times about a sewage like smell in our finished basement.
happened again today, which I have confirmed.

Wondering if anyone has any ideas of the source.


some details:
- bungalow with finished basement (also has a walkout)
- lakefront home
- municipal water and sewer
- heat pump and a/c - no gas
- active sump - although I havenít heard it much lately. It rained here on friday
- did a load of laundry today
- no basement floor drain
- ran the water in all basement sinks/shower after discovering the smell (maybe the traps were dry?)
- smell seems strongest at the west end of the basement (located below 2 main floor bathrooms)
 
  #2  
Old 06-14-20, 07:24 AM
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How old is the house/plumbing system?
Unfortunately a sewer smell can be from a plumbing issue, or it could be from other things too. I had an issue where mildew/algae in the AC condenser drain would get sucked into the AC when it was running, and smelled like something had died. Some bleach down the condensate line would fix it for a while.
Similarly, mold or whatever growing in a sump that isn't used often can cause awful smells.
Plumbing vents can too be an issue, though unless the plumbing was installed completely incorrectly, or a pipe broke, it's less likely.
 
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Old 06-14-20, 07:29 AM
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House is 40 years old.

a/c currently not running.

should clarify...sump runs multiple times a day.....although not hourly like during the spring.

 
  #4  
Old 06-18-20, 08:31 AM
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Smell returned today when the washer/dryer was operating.

perhaps we should move this thread to large appliances.

Definitely seems related to the clothes washer.
 
  #5  
Old 06-18-20, 10:17 AM
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Hmm, not sure why the clothes washer/dryer would be making that smell though. Unless there is something inside causing it. I would look into it to see if maybe there is a dead mouse or other animal. Something similar happened to a friend of mine, he ended up finding a dead mouse inside his dryer. Another time we found a dead mouse on the engine of our RV. We didn't know for a while, so there was a really awful smell. I can see it being confused with sewage maybe.
 
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Old 06-18-20, 10:23 AM
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Iíll need to isolate washer and dryer usage next time to see which one is causing it,

I did run a ďsanitizingĒ cycle in the washer according to the manufacturers directions.

we donít use bleach every week so maybe some bacteria is building up in the washer, down pipe or trap?

if you google sewage and washer, there are quite a few hits.....most seem to say clean the washer and and trap with straight bleach.
 
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Old 06-22-20, 01:50 PM
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Smell was back today, and even though we did laundry, the smell was Definitely coming from the room located below the main floor bathroom. Now I donít think itís laundry related.

the ceiling is finished in drywall, but there is a hole cut in the ceiling (covered by a return air grate). Its covering the bathtub trap. I guess there was a leak or a new tub put in that required the ceiling to be cut open.

stuck my face in the hole, but I wouldnít say the smell was any worse.

Iím super perplexed. Whatís causing this and why does it only occur from time to time?
 
  #8  
Old 06-26-20, 09:53 AM
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Hi, can you see above the ceiling to where the toilets are located, could possibly be the wax ring has somehow deteriorated and leaking water through the floor, are the vent pipes on the roof clear, no nests etc.
Geo
 
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Old 06-26-20, 10:24 AM
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I canít see the area directly below the toilets...the floor joists are in the way. They only exposed area in the ceiling is where the tub drain is.

never thought about the toilet wax rings.....wouldnít the smell then be there 24/7?
 
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Old 06-28-20, 02:55 PM
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Dead Animal

Sorry about the smell in your basement. the only thing that I can add is that if the smell is being caused by a dead animal it should not last more than 2 or 3 weeks. After the process where the body of the dead animal is decomposed, the oder goes away after two to three weeks. I have lots of experience with this because I own three houses here in the Bronx and I have unfortunately dealt with lots of issues with rodents.
 
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Old 06-28-20, 04:28 PM
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The smell is intermittent. The only I think I know for certain is the last 2 times we smelled it, the laundry was being done. Have yet to isolate the washer or dryer operation to determine which one, if either is contributing to the odour.
 
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Old 02-03-21, 12:24 PM
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Reviving this old thread. My daughter is spending more time down in the basement. The intermittent sewage smell continues. Itís seems like itís only in one room which is directly below a bathroom, fully finished drywall ceiling. There is an opening in the ceiling where a plumbing repair must have taken place as the opening is right below the bath tub trap.

I stick my face near the opening, but I wouldnít say the smell is any worse. I think we can rule out dead animals as this has been going in for some time.

Could a vent be leaking from somewhere? I donít see any water stains or leaks in the basement. All the tubs and drains are used often so I donít think itís a dried out trap.

I did find another plumbing anomaly last year. Our kitchen is roughed in for a washer and dryer. I had to take down some drywall behind the kitchen cabinets for another issue and I discovered the roughed in washer drain didnít have a cap on it.

Iím wondering if the bathroom/basement has some other plumbing anomaly. Canít explain what itís intermittent?

how would a pro try to resolve this?
 
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Old 02-03-21, 02:11 PM
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Did you ever replace the wax ring in the upstairs toilet?
 
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Old 02-03-21, 02:35 PM
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I did not.....I suppose that’s the easiest first step. But we never have smell in the actual bathroom, only in the room below the bathroom.
 

Last edited by zhy987; 02-03-21 at 03:11 PM.
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Old 02-03-21, 05:24 PM
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Sh.. I mean poo flow downhill. So, down is where leaks and smells often go. Many toilets are also installed with a bead of caulk around their base which can prevent a leak from going noticed or smelled.

If this is the only toilet in your house go shopping first. I would get a standard wax ring, a jumbo wax ring and a set of toilet hold down bolts. That way you can deal with the most common issues you might run into when installing a new ring. If you don't need one of the wax rings or bolts you can return them but it's great to not have to make a shopping trip in the middle of a project.
 
  #16  
Old 02-04-21, 01:57 PM
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Years ago we had a similar situation with sewer smell in our basement whenever laundry was being done. We checked everything we could think of (venting, cleanouts, drains, etc.) We have unusually high ceilings in our basement, (over 10'!) so had to use a ladder to get close to the laundry plumbing and to check our toilet plumbing. Never found any leaks, but managed to find there was a loooong crack/rotted area in the top of the cast iron sewer pipe!! (Not noticeable from standing on the floor!) We yanked all that out and replaced it with the traditional plastic piping. Never would have suspected that!
 
  #17  
Old 02-04-21, 06:10 PM
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Considering you consistently smell it with the laundry, I'd start with that. Either a bad vent, missing trap, rotten pipe, etc. Something with the laundry draining causes something to get agitated and smell.

Can you see how the washer drain is plumbed? Trapped/vented? All newer PVC pipe?
 
 

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