Let me describe my house and what I have done to it and then describe my problem. Please bear with me, read my information, and hopefully somebody out there will have the answer to my issue.

I have a 1 story ranch style house I purchased 5 years ago, (in 2010). My house was built in 1995. The house sits on a concrete block wall foundation with a crawl space. Although it's technically called a crawl space it is actually a "walk-in space". On the side of the house the entrance to the crawl space is on there is about 8 - 8 1/2 feet of clearance, and on the opposite side about 5 1/2 - 6 feet.

So when I bought my house 5 years ago I basically gutted the inside. I will spare the details that are not important to this situation but what is essential to this situation I will explain. I ran out of money by the time I got to the kitchen, except for buying and installing a new dishwasher, (I had it installed by a professional plumber). There is a Double Bowl 16 gauge Stainless Steel Kitchen Sink, and in one side of the sink I had my plumber install a new InSinkErator Badger 5 - 1/2 HP Garbage Disposal.

I have two bathrooms in my house, one is off the hallway and the other is off the master bedroom. The bathrooms are actually identical, except they are mirror images of each other. The bathtub / showers are back to back, the toilets are back to back, and the sinks are back to back. I didn't do anything do anything with the bathtubs except replace the shower nozzle heads. The bathrooms had linoleum flooring, so I removed the toilets myself, left the vanity cabinets, and I had a professional lay tile flooring down in both bathrooms. My plumber suggested what toilets would be good to install and he had me buy two Gerber toilets, Model VP-21-519, Viper - 1.6 gpf, Compact Elongated, Ergoheight toilet. Each bathroom has the original oak vanity base, however I did replace the vanity top, and the faucet in both bathrooms. I don't recall what the vanity top models are, (I doubt it's relevant), but the faucets are both delta brand.

So very shortly after the "remodel" was finished and I finally moved in, I started smelling this sewage odor. It was quite strong throughout the whole house, but it seemed like it might have been originating in the bathrooms. I learned to live with it but after a couple years I met who is now my wife, and after moving in she too smelled the sewage smell and asked me to find and fix it. I had the plumber who did all my work for me come and check out the smell. He said he could smell the odor as soon as he came in the house but couldn't identify or locate it. I told him it seemed like it was coming from the bathrooms, more specifically the toilets, and he suggested that something could be wrong with the wax ring seal. So he removed both toilets and wax rings, and installed new wax rings and reset the toilets. That didn't really seem to help. He came again and checked all the normal smell culprits and added extenders to the vent stacks on the roof, checked the traps on all 3 sinks in the house, (1 in each bathroom and 1 in the kitchen), and did "everything he could think of", his words, but couldn't fix it. So I had another plumber come and take a smell at the house and almost instantly detected it coming from the toilets. He noticed the toilets were not sealed to the flooring tile with caulk, and he sealed the base of each toilet for me with caulk. That helped the smell some, but after a while we started noticing it again.

I had him come back and check again and he couldn't make any more headway after the caulking. I had a third plumber come and he also checked everything he could think of and was no more successful than the previous two. Although recently I was working down in my crawlspace and I smelt the sewage smell quite distinctly. I followed my nose and ended up over at the drain pipes that come down from the toilets. I removed the insulation and saw that the wood sub flooring had a hole cut in it for the pipes to come through, (which obviously they needed to do), but the hole was nearly twice as large as the drain pipe. And once I had pulled out the insulation and further exposed the area the drainage pipes were coming from I was hit quite hard with the smell. I had some of the expanding foam sealant that comes in a spray can, and I used that to seal up the excess space between the pipes and the flooring around it. Almost instantly after that I noticed the smell decreased quite a bit. And over the next few days or maybe a week or so we didn't smell the odor at all and thought we had finally fixed the problem.

However the smell "came back" and we started smelling it again. My wife's nose is more sensitive than mine so she notices sooner and more often than I do, but she says nearly every night around 9 or 10 pm the smell appears. It now is definitely coming from the bathrooms, but also from the kitchen. Mostly from our master bathroom off our bedroom. The smell is much much stronger in our bathroom, and bedroom if the door is left open. And although it can sometimes be smelled in the other bathroom it's not nearly as strong. Sometimes the smell originates in the kitchen as well.

So we can identify that smell is coming from the bathroom and the kitchen, we can't pinpoint exactly where, (like an air vent, or sink). There is no floor drain anywhere in the house. The only drains are from the sinks in both bathrooms, and the sink in the kitchen. It is a double sink and one has a garbage disposal as I said, but they have separate drain pipes. All of the sinks (including the one side in the kitchen without the garbage disposal) get used regularly. There are no sinks where the traps are drying out. This is no common problem and none of my local plumbers are of any help. I desperately need someone who has come across this problem before or has some wise and expert advice with these kinds of problems. If you have any suggestions please let me know. Like I said this is no ordinary problem where a common solution is readily available. But if there is something you think I or my plumbers have overlooked I welcome any possible explanations.

It could be the toilets themselves. I once ran into a similar situation and after a smoke test was performed on the drainage system it was found that the toilets were faulty from the factory and allowing sewer odor up thru the tank.
In your case it should be a simple matter to pull the toilets, , remove the traps from the sinks , plug the drains and perform an air test on the DWV system to locate exactly where the leak is.
Some might even suggest a peppermint test to locate the leakage, with the liquid poured down a roof vent.

Is there a possibility that a vent pipe in a wall was cut during remodel and left in that condition? Have you checked the vent system in the attic?

No drywall was cut, removed or touched. I stripped the house down to the drywall but didn't actually do any wall knocking down. Simply patched nail holes and what not, sanded and painted the entire house. But no I do not think there is any damaged pipes inside any walls.

And I did check the pipes in the attack. The air stacks or whatever they are properly called go directly to and through the roof as they should. Nothing out of the ordinary.

I doubt it's the toilets themselves. As I said once the toilets were caulked the smell drastically lessened, and after I sealed up the extra space under the flooring the smell coming "from the toilets" all but dissipated. However there is still a sewage odor in the master bathroom and from the kitchen. My wife said she cannot exactly pinpoint where in the bathroom it is now coming from, but in the kitchen it seems to be coming out of only one of the two sink drains.

Like I said this is a very strange problem. Every time I think I have the problem licked the smell calms down but then "returns" from a new point of origin.

DWV is the drain, waste, vent system right? I assume it would be best to let a professional handle that kind of air pressure test. Do you know anything I should specifically tell a plumber so they know what my problem is and what to test for? (As I am ignorant of all but basic plumbing information and lingo I could very easily misrepesent my problem and have a plumber waste his time and my money doing the wrong thing.)

a smoke test will locate any leaks...
[www.google.com]

One of my plumbers did a smoke test, (or so he said, I was not home at the time), but said it did not help identify any signs of a major leak or a cracked or damage pipe.

Like I said this sewage odor smell problem is quite difficult. Most sewage smells are not super easy to identify but this one has seriously stumped me. But I'm hoping one of you out there will have some knowledge or insight or wisdom into this particular situation.

id stop trying to hide/cover up the issue with spray foam or caulk, and fire any pro who even thinks to suggest that.

Sounds to me like a broken pipe probably in crawl space, maybe as from your description the toilet flanges aren't properly anchored to the flooring/structure, maybe as people sat on the toilets there was some flex occurring on the pipes?

Alternatively, is there a floor drain in the basement floor?

Nope to the floor drain.

I thought about the toilets not being properly sealed, and even though they hadn't been in the house very long (a couple months at the time) and I was a single man living alone so it's not as if they were being used by a family many times daily, my original plumber who installed the toilets suggested the very same thing. He said it would cost me something like 50 or 100 dollars, (this is almost 5 years ago so I can't recall exactly), for each toilet since the problem he thought it might be would have only come from "wear and tear" i.e. sitting on the toilet causing the flange and/or pipe to flex and crack/break/come apart/or whatever. So he came and turned off the water, emptied the toilets of water, pulled them both up, scraped out the "old" wax rings (old in quotations because as I said at this point it had only been a couple months), installed a larger or different type of wax ring (his thinking for this was because I had the bathroom floors tiled the new toilets would sit a little higher and hence further away from the flange or pipe or whatever it sits away from and there might have been a gap causing the smell and this larger or different shaped wax ring whatever they were, were supposed to help give the toilets a better seal. So after paying the 50 or 100 bucks, PER toilet I was still no closer to a resolution.

Like I stated above this problem has been ongoing for over 5 years, and I've had 3 different plumbers try "everything they could think of" and have gotten almost nowhere in these past 5+ years. But as it seems that it is most likely my local plumbers are of a poorer quality than even the average joe professional plumber out there, I am kind of out of options and throwing my hands up for a hail mary here hoping someone can point me in the right direction and I can finally rid my house of this horrible smell.

Allow me to weigh in here first by saying that odors are without question the most difficult plumbing problem to diagnose. I actually happen to be pretty good at it mostly because I was blessed(or cursed) with a pretty good nose. I wish that you were in my area because I enjoy these challenges, but you're not so I am going to first tell you some of my most common plumbing related findings in relation to odors; number one is without question a poor seal on the toilet.- After that - cracked cast iron vent in the wall - undersized or poorly pitched / no pitch on vents in attic, - nails or screws drilled/hammered into vents-while installing; upper cabinets, crown moldings, medicine cabinets, tv support brackets, large pieces of art hung on the wall. - And poorly glued or completely unglued pvc pipe and fittings.

Now, how do you find the culprit? Well a good nose certainly helps so you may need to enlist the help of your wife on this one. I take a 2 -3 foot piece of clean 1-1/2" pvc pipe and place one end up to my nose and the other methodically sniffing out each of the areas mentioned, you must first clear the room of all odors and have fresh air only. Then room by room carefully sniffing through the pvc go over everywhere there could possibly be plumbing or adjacent walls. I have found many leaks on stacks by sniffing electrical outlets, recessed light fixtures, penetrations for tv mounts, forced air vents, along crown moldings, clothes chutes, etc.

It does sound to me that you may be dealing with a poorly glued topside joint in your crawl. So you are going to have to use my sniff tube method and go over every joint in that crawl, remember this as you do so; odors are highly susceptible to air movement so just because you smelled it near your toilets in the crawl does not mean that it didn't originate 20' away.

By using this method you are concentrating the odor from the location you are testing by inhaling deeply 2 or 3 times at each testing point if you are diligent enough you will find it, and by using this method when you find it you will know it without question the higher concentration will smack you right in the face.

I have found some pretty tough ones with this method in many cases where multiple other plumbers had failed, some actually quite amusing. But I think this one is going to have to be you and your wife being methodical and dilligent, btw it is common for these odors to be more prevalent inside a home at night and this is because the air pressure changes outside more than inside causing an air draw into the home. However with that sniff tube it won't matter what time. Good hunting

Once you solve this, please post an update so everyone can learn about how you did it.

I second the idea about pressure testing your entire sewer system. This would rule out the pipes themselves if there is no leak. If there is a leak, then finding it will be difficult. The previous poster gave a lot of great ideas. I have another suggestion: buy a H2S (hydrogen sulfide aka sewer gas) meter/detector.

In addition, consider using plastic sheeting to isolate each room of your house. This way, you may more easily find the areas where the smell is most concentrated.

You can also plug all the drain pipes and fill the entire DWV system with water from the roof vent. Obviously, this could make a major mess/flood if you have serious leaks or fail to plug all drain openings. But it might be an option if you've exhausted all other ideas. As an alternative: If your leak is small , you could fill the DWV system with compressed air instead of water and listen for air escaping(hiss sounds).

Good luck. I could not imagine living with this situation for years.

Been raising 7 boys for 24 years, never had a smell like the one coming from our Gerber viper toilet we had installed 6 years ago.the smell pervades the entire main floor and wafts upstairs. Terrible. While cleaning it again this morning with bleach I noticed the smell was stronger near the front of the inside of the bowl. I put blue toilet bowl cleaner in, coating the sides of the bowl then flushed, I noticed the water didn't wash away the cleaner in the very front part of the bowl. Upon closer inspection I noticed that hard water and filth had collected and created a mass of smelly caked junk. I used some elbow grease and scaled it away. The toilet is not rinsing the entire bowl when it is flushed, so over time, the urine and hard water are building up and causing the stench. I miss the toilet that was in that bathroom original to this 1948 home. That thing flushed like a tidal.wave!