It sounds like sewer gas. Do the odors come from the kitchen and bathroom simks too? If not it sounds like there are no traps in your tub or laundry areas. The traps are "U" shaped and they trap water and keep these odors from comimg up from the sewer or septic. Look under the house at the tub drain and inspect the pipes in the laundry area too. Let us know.

Thanks Christopher for the response. No, the odor comes only from the laundry room and the adjacent bathroom (but not the sink in that bathroom or from the toilet). Nor does it come from the bathroom at the end of the house, or the kitchen.

Since the drain cleaner did not clear it up, I used a plunger in the tub, and it definitely cleared up about 85% of the odor in the bathroom. But it did not help the laundry room. I'm going to use the plunger again tomorrow.

Another oddity about this situation is that when doing laundry and the washer is draining and spinning, the water in the toilet bubbles and gurgles. Also on occasion, the sink faucet makes a groaning sound when it is turned on.

So when you mentioned that there maybe no traps, it sounds like that may be the reason for these problems.

Is there also supposed to be a vent?

Thanks for you help. In the next few days I'll make a trip under the house and check for the traps.

Nick

No traps was my first thought but since the toilet bubbles and gurgles when the washer is draining, check the vent stack. Smells would happen and things wouldn't drain if the venting is wrong or plugged. Non vented sewer gas can and does kill so get on that right away..

The faucet groaning is a completly different issue

Your vent stack may be plugged with a bird nest or squirrel nest. You need a plumber to check it out.