Our upstairs sink smells when you run water in it. I have tried bleach down the drain, which works temporarily and then the smell comes back. The downstairs two baths are also getting a sewer smell from the drains. I am afraid, given that it is happening in multiple baths, that it may have something to do with a poor sewer line from the house to the street? A friend's line in the next neighborhood over failed, and I'm wondering if it's a sign that its happening to me to? How would I tell?

Suggest that you pour a small amount of water down the drain (pour slowly) when you smell the odor. If the odor ceases that will confirm that the odor is coming from the drain. If the odor returns after using the sink or something else, like a toilet, that would indicate a blocked vent and the traps are being siphoned dry.

Is there any gurgles or sounds when you flush or drain? Back to you, Tom

I don't hear any gurgling that I have noticed. THere is a lot of knocking in the pipes when the water is running . I have tried bleach down the upstairs sink, and it removes the smell temporarily... it comes back after a week or two. Running water in the basement shower and sink seems to help. Same with the main level shower. The main level sink gets regular use, but not the shower, the basment shower and sink are rarely used, and the upstairs one is in heavy use.

What worries me is that there are so many of them smelling, that I fear something systemic. How would I know if it was a sewer line problem.

City sewer or septic? This could be your vent stack clogging up. That could siphon the water out of your traps, that's why TOm is asking about gurgling. Have someone with you and test each drain, shower, tub and toilet, hear anything like gurling? " I fear something systemic" yes, that could be the vent stack.

Not septic... city sewer. How would I check/clear the vent stack?

Before I answer that please tell me your age, how tall your home is,pitch of the roof and the current weather in MA. Sounds silly but your answers will affect my directions

Home was originally built in 50s, remodeled significanlty in 90s. We bougth it about a year ago. It is tall, with a steep roof. Weaterh in VA is beautiful... spring and 70-80s

Thanks, what's your age and is this a one or two story home? "weather in MA" sorry confused you with another poster, VA got it.

40s, and 2 story.

Your age works for cleaning the vent but not on a 2 story steep pitched roof. Maybe call 3plumbers for estimates. To clear a vent stack you need to get up on the roof with a sewer machine and rod down the stack roughly 40'. The sewer machine is heavy and will not sit on the roof so so brave soul would have to hold on to it while keping himself from sliding off the roof. I would not even try this myself. The falls do not hurt but the sudden stop is not good.

Age discrimination, age discrimination . Bob, the young whipper snapper that he is, doesn't think old people like me should get up on the roof.
Santa Claus is old and he still gets up on my roof every year.

I know for a fact old guys like us need to stay off 2 story roofs. It's that sudden stop thing when you reach the ground.

Thanks for your help. "Young" or not, you're right--I'm not going up on the steep roof with a big machine as you describe. If I run water in the drains and that takes care of it for a while, and there's no gurgling, does that tell me I'm probably OK?

You can certainly try that but clogs do not often cure themselves but it has happened. There are a great many plumbing issue we can walk you through but this might not be one of them. If the issue continues ask 3 plumbers to evaluate your plumbing and give you a bid for their fix.

Another possibility is from the attic. If the attic access is such that you can get the snake up there and the pipe is PVC, you can cut the vent pipe and snake the vent then reconnect. Should be able to use a drain snake as opposed to a sewer snake. Only need to break the clog, not clean out the pipe.

I would agree but only if the stack is PVC. Too many people cut cast iron lines not knowing what tremedous weight is up there. I do prefer a sewer machine over a snake due to the size and the action of a machine.