We keep getting a sewer smell coming from our shower drain. We put drain cleaner down it and that seems to do the trick for a while. Water goes down ok. Do not have any other drain problems. I was thinking maybe the rubber connector has something to do with catching shower scum but cant see connection due to finished basement hiding drain lines.
Any suggestions?
"Semper Fi"

same old coat on another drain issue.

issue: the trap dries out over time as water evaporates into drier air above.

solution: get a 5-quart bucket, fill it with water, and run it down the shower, floor drain, guest toilet that gets used once a year, laundry sink drain, yo' momma, whatever. it's common for this to be a janitorial duty once or twice a week in every drain in a commercial building. once a week should suffice in a home.

if you don't have the affected drains vented, a heavy load in another drain could pull the water out of the trap every time. this gets old. it should get you to insure all drains have vent air behind them, for beyond the gases of decomposition from the drain including poisonous hydrogen sulfide, there is flammable methane coming up.

as in natural gas.

so if bucketing the unused drains weekly doesn't do it for you, you need a plumber, and depending on the surroundings, a banker.

minimum code says you sorta don't need a vent if the trap is plumbed direct to the stack within a 6 foot distance. this only works if the drain is used a lot and water stays in the trap. if there's a lot of it in your house and water doesn't stay in the traps, then minimum code didn't work in this case. you'll need a lot of retrofitting in that case. the commercial trick of putting the drain in a loop from the stack, to the fixture drain, to the stack would be the easiest way to fix it.

there is a "burp" vent, I think it's a Studor vent, that is a flapper valve that can be installed at unvented sinks, etc. they have moving parts and can fail. it's illegal in some jurisdictions because it fails to an open drain pipe. direct venting up a pipe and out the roof should last 60 years or longer (spec-60 plumbing.)

This message has been edited. Last edited by: swschrad,

And another possibility - If the shower floor is tile then it's set in a pan with a liner. Fairly common for old, scummy and smelly water stuff to remain trapped within the mortar and liner of the pan. This will get quite rancid and the smell will be released from around the drain area and any grout cracks in the base. Note that if you have a solid surface or fiberglass base then this is not your problem and is more likely the issues that swchrad mentions.

Troubleshooting:

1. Plug up the drain, pour in a mix of water & bleach - enough so that it's about an inch deep around the entire perimeter of the base. Let it sit for a few hours and then drain it out. If it is a problem with sludge trapped within the pan, then the odor will go away ....but only for a few days.

2. If you use your shower frequently then it's unlikely to be the dry trap issue