[LiquidFeet]

I have an odd problem. Sewer gasses are coming out of my shower drain. I've eliminated lots of other causes, and am left with a stuffed vent/waste stack as causing the problem. I can't see a pvc pipe-style-vent coming out of the roof, so it must be either connected to the roof vent, the one with a housetop on it that looks like it just vents air, or maybe the waste stack vent vents into the attic, which can't be gotten into. I'm at a loss as to what to do.

I do have a squirrel in the attic. I hear it at night. Can't find its access point, either.

How do I clear the mysterious vent pipe, if that's it?

[speedball1]

If your house vents are terminated in the attic then you really do have a sewer gas problem. Don't let this slide get into the attic and check. As for the shower smell try this. Most bad smells in tubs, lavatorys and showers are caused by rotting hair matted with grease from the soap and from rotting food in kitchen disposals Try this for the smell. Tonight before bedtine Take a 1/2 gallon of bleach and pour it down the drain and let set over night. Next morning ,(and this is important) flush out the drain with two large pans of boiling water to loosen the grease and flush the mess out. The bleach will make the hair slippery and began to dissolve it and the hot water will melt the grease and flush the mess away.
Also, pull the lavatory stopper and look down the drain. About 4 inches down you'll see a small rod sticking out. Fish out any hair that's caught there and do the same thing to the lavatory if you detect any odor. This should make your drains smell better. With all chemicals used in drain cleaning proper ventalation should be observed. Good luck, Tom

[LiquidFeet]

As for the shower smell try this. Most bad smells in tubs, lavatorys and showers are caused by rotting hair matted with grease from the soap and from rotting food in kitchen disposals Try this for the smell. Tonight before bedtine Take a 1/2 gallon of bleach and pour it down the drain and let set over night. Next morning ,(and this is important) flush out the drain with two large pans of boiling water to loosen the grease and flush the mess out. The bleach will make the hair slippery and began to dissolve it and the hot water will melt the grease and flush the mess away.

I am on a septic system. Can I safely put that much bleach down this drain?
What I've done so far is use Draino several times following directions, use bleach several times, tried other cleansers, got down into the drain and used vinegar and then something more powerful to clean out hard mineral-type stuff that had accumulated within reach. I've stuck a short plastic thing down the drain to clear out hairs, but nothing really long have I put down there. But I've never poured a half gallon of bleach down the drain, and I've never followed with boiling water the next morning.
The smell coming up from this shower drain is not sewer-like; it's more like the awful smell you get at a hair-dressers, where people are getting perms. It's a very chemical-like awful smell, and intolerable. And it doesn't come up from the sink right next to the shower. It goes away if we don't use the shower. It's worst right after a shower.

[ballengerb1]

Skip the bleach and draino if you have septic, the first gallon should have been enough. Find the vent in the attic and one way or another make sure it goes out through the roof when you are done. Since you already did bleach now try something that will not further kill the arobic bacteria in your septic. Mix 1/2 cup of table salt with a 1/2 cup of baking soda, dump into the drain. Follw it with a cup of vinegar, tomorrow a bucket of real hot water.