When we run our washing machine, we get a rotten egg smell in the house. We have lived here for five years and have only started noticing this for the last 6 months or so. The smell does not seem to be coming from the laundry room but rather at the other end of the house where the two bathrooms are but I have been unable to pinpoint the source by sniff alone. I tried running the washing machine without clothes, set on hot, and adding about a quart of bleach but the smell still appeared. If we do multiple loads of laundry, the first load is the only one the seems to produce the smell. If I do a load on Monday, the smell is there. If I then wait until Tuesday to do another load, the smell is there again. Nothing else seems to produce the smell when used, not the dishwasher, the showers or the toilets. I really don't know much about plumbing so I don't even know where to start to figure this out. Any help will be appreciated.

It's hard to say without looking at it...but it smells like you might have some "trap seal loss" going on...this could be for a number of reason, but most commonly caused from improper venting...again, hard to say but if you find the smell you would have a better chance...is your laundry vented?

Washing machine discharge especially the sud spin out can put a load on the drainage system.Try listening in the bath with the most odor when the machine starts to discharge .If you here a bubbling noise or the sound of water moving you may find the odor source.You may be able to watch the water level in a shower trap moving up and down indicating a poor vent or participially clogged drain.Do you know where the clean out is on your building drain or sewer connection?Accessing this cap could help determine what type of problem you have.

is there a floor drain neer the smelly area?
check to see if the clean out plug has been removed and there is water in the trap.
the only other sugestion i would have is to make shure you have a p-trap on the washer dicharge tube.

Finally found the site where I posted my question and was happy to see some replies. I'll do the best I can to answer the questions posted.
Yes, I believe the laundry is vented. There is a hookup for a gas dryer (ours is electric) in the room but I do not see any type of exhaust for that so I assume the pipe coming out of the roof over the laundry room is a sewer vent. I climbed onto the roof and did not smell sewer in that pipe though.
I'm not sure if I know where the cleanout is for the house. Coming out the exterior wall of the laundry room, about 1.5ft above the ground, is about a 2in pipe or so with what looks like a cap screwed into it. Might that be it?
There aren't any floor drains in the house. Is there any way to check to see if the drains have a trap on them besides tearing a hole in the wall? By the way, my house is on a slab, no checking in the basement for me.

that is a clean out but it is for your washing machine line and is to small to use to clean the main line.

all traps except for tubs/showers and the laundry will be exposed . basically if you can see water standing in the drain pipe you most likely have a trap.

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PLUMBERS "Protecting The Health Of The Nation"

sounds like you really should have a plumber come and see the how the drainage system is plumb.if everything else in the house is workn fine and you have always had this odor some handy man may have done the plumbing wrong.

Yea pull the cap off/Unscrew it and remove. and leave it off for the next few uses.Or days.If water comes out clear the drain line.You could have a wm line clog but I am seeing main or septic.

why take the cap off a sink cleanout? the sink doesnt put enough water in the line to fill it that much without them already noticing a problem with the drain, other than the smell

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PLUMBERS "Protecting The Health Of The Nation"

Well, we ran 4 loads of laundry today and my nose and I were on the case. The smell began eminating from the master bathroom, which is on the complete opposite side of the house from the laundry room by the way, when the washing machine would empty prior to the rinse cycle. Armed with a flashlight, I looked into the sink and shower drains when the smell began. The sink drain had water in the bottom of it, no problem there I guess. I looked into the toilet bowl which also had water in it, no problem there either. I looked down the shower drain and saw bubbles. Not bubbles bubbling up through the water, soap sud bubbles. After the washing machine was done doing its thing, I ran water down the shower drain and flushed all the suds out. I estimate there was about 3-4 inches of bubbles in the shower drain. After flushing the drain out with water, there was still water in the pipe. In other words, it's not dry. Am I guessing correctly that there is at least a partial blockage downstream of the shower drain which backs up the pipe as the washing machine unloads its drum? I don't know much about plumbing but I'm guessing that seeing the soap suds in the shower drain is a clue to something. By the way, the shower drain goes down into the slab under the house so I'm not sure what, if anything, I can do about a problem in that area. Suggestions? Anyone?

yes that is an indication of a problem downstream but if it is a restriction of just bad plumbing practices we can not say from here

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PLUMBERS "Protecting The Health Of The Nation"

I guess I haven't mentioned it but the smell has not always been present. We lived in this house for years with no problems using the same washing machine so I think it is a recent development. Some type of clog in or near the drain for the shower that my wife uses (who has longish hair) seems like a perfectly reasonable answer to my problem. Anybody have any suggestions of products I can try to loosen up a potential clog without knowing what it consists of? Or is this a call a plumber type of thing?

you could have a restricted main drain line.

Sorry if a tool long enough to hit the water of the trap in the shower does not clear the clog.You have to think main line....