FOLLOWUP! In July 2012- I had sewer gas leaking into my bedroom, bathroom, and then up to the upstairs level of the house for five months. It was awful. I have an 18 inch crawlspace and a raised floor. Under the house is dirt and the pipes. I had FOUR plumbers and TWO handymen check it out. They found NOTHING! They were too big to fit around the pipes!!! We had put in a new toilet, and I had that pulled up and put down again, just in case. but that was fine. We checked all the traps, and now keep them full of water, so they are fine. The plumbers gave me estimates of $4500 for a sewer cleanout installation in front of the house, and $6800 to repipe the bad pipes, if they found any.... I did not have the money, and they really had no plan, just guesses. Last August 2012, I luckily found a neighbor friend who was able to crawl around under the house. He was a little guy, and knew how to do plumbing and other repairs!! He found leaking and large cracks in the main drain sewer pipe at the ground level, around the back of the pipe, hidden from general view and he used epoxy to repair it. This pipe was attached to other pipes, and if it needs to be replaced it will be a difficult job. That pipe was directly below the downstairs bathroom. That reduced about 70 % of the smell and seems to be holding tight with no more leaking there. But sewer gases were still leaking from somewhere else, but not as bad, or as often. it still kept coming back about every three days.They centered in my bedroom, and seemed to come out of the floor. Oddly, from the beginning, the gases only happened around 1am until 5am, then stopped all day long, so no one could smell them, unless they stayed all night. From the first repair, the gasses only occurred about every three days or so, and not as severe, but still stinky. My friend came back into town in November, and went back under the house, and found stress marks on the larger pipe that attached to the MAIN drain sewer pipe, and ran towards the front of the house. This pipe traveled directly under my BED, and the cracks were basically under my pillow area. (What LUCK!) He had to replace that whole pipe, and to get it inside we opened the ground vents and slid it through, and the old pipe out. After he replaced that and all the fittings, the gases were gone! THANK YOU GOD!!! It cost me $800 just to investigate all this, and get nothing for the repairing of it from that! Plumbers were just ready to get paid, with no idea what was actually wrong!!! My friend only charged me $550 plus parts for this! I suffered through it for five months, and hope the sewer gases didn't harm me in any way! I sure appreciate the clean smell now!!! By the way, it was an acrid stinky burning smell. It did NOT smell like METHANE, or anything described as general sewage smells. It was just hard to breathe it, and would cause eyes, throat and nose to burn. I had a runny nose right up to the day the last pipe was replaced, and it all stopped. GOOD LUCK TO ANYONE STILL HAVING THIS PROBLEM. I learned far more about plumbing than I ever thought I would need to know!

If your not using that drain you should pour about a quart of water in it monthly to insure the trap stays full. After you pour the water in you can also pour a couple teaspoons of cooking oil in the drain. The oil will form a film over the water and retard evaporation.

Sorry, forgot to clarify one point. The strongest odor is from the tank, not the bowl, not the sides. I was really strong with the tank lid off, much better with it on. I know it doesn't make sense. That's why I'm asking more knowledgeable people than I :) This toilet has a Fluidmaster fill valve. The flush valve is the Caroma 3/6 litre dual flush. I can't really see how it works without taking it out. The flush valve is different than the two 2-piece Caromas we have, both of which never had any odor.

It may not be what you want to hear, but I would have it checked by a professional as well. You can not be too cautious in a situation such as this. As far as the smell in the clothes their are some things you can do to help that. Baking soda is useful, but in my experience, not up for heavy duty smells. I would run a clean tub. You can use affresh tablets or bleach. For a lot of mold or just build up it may take a few clean tub cycles ( or the longest, hotest, extra water cycle you can run) to clean up the machine. I have heard some people use a Lysol concentrate, in a brown bottle for laundry disinfecting and odors. I have not tried that though. For odors in laundry I have had good success with oxygen bleach, borax, ammonia, and OdoBan. Use the hottest water you can for the fabric, and along with a good quality detergent ( this does make a difference) just add in something for odors. Odoban can be bought from home depot for $10 a gallon, and you just add in ½-1 cup. This has always worked for me. Borax can be bought at target for $4, you can add ½-1 cup per load. You can also soak them in a borax/detergent solution, sometimes the extra time really helps with odors. Oxygen bleach like oxiclean, oxymagic, etc. Also helps with odors as well. My sister does her laundry at my house sometimes, she works in food service. Her clothes reek!!! After reading some posts here, I decided to try ammonia in her load of clothes, ½ cup. Works every time, no oil stains, no horrible smells, just clean fresh clothes. I never would have thought to use ammonia, it smells bad, but works. Just NEVER combine bleach and ammonia, or you literally risk your life. Good luck, and let us know how everything works out.