Whats That Smell? This time its a dead critter!

In the never ending pursuit of methane and sewer smells, I continue to get great letters about situations that I haven’t covered or that are new. The one I received this weekend requires that, in the future, I’m going to have to bone up on my pest control knowledge.


Here is how the problem unfolds:

Q: Thank you for such an informative site. We have a similar problem. About a week ago our master bathroom drains were a little clogged, so my husband treated them (sink and separate shower) with drain cleaner. I don't recall if our methane odor began before or after this, but we now have a terribly strong methane odor in there. Our plumber came and said he wasn't sure if the pipes were clogged somewhere. Our p traps had water in them, however the tub trap was not accessible (but it is used about twice a month). He also gave us some sort of bio additive to put down the drains to eat the bacteria. We did this for 4 days, but still have the strong odor. Our plumber recommended a cesspool/plumbing service to scope our pipes for leaks with a snake with a tiny camera. They came today, but sent the cesspool guy as opposed to the camera/plumber guy. Today's man opened our vent (we are in a ranch on a slab) which is near our front door, and looks like a large pipe coming out of the ground. Upon flushing a toilet in the house, he told us it was running slow/clogged. He charged us $400 to snake the line and add sulphuric acid. I'm feeling ripped off tonight as we still have the strong methane odor and now the rest of my house smells like sulphur. I don't understand how a clogged vent would only make the methane smell in one bathroom? Another bathroom is closer to the vent as well as our kitchen. Do you have any other suggestions? Any help would be much appreciated. Additional info- house is 19 years old, cesspool has never been serviced to my knowledge, but we do put that "good bacteria" into the lines every few months. Nothing is backing up. Only symptom is the smell in the one bathroom. Thank you in advance.

A: Many things can cause smells in a bathroom. The first thing that comes to mind is that the wax ring under your toilet has deteriorated. Aggressive chemical use or augering can cause these wax rings to fail or slip out of place. Pour a small amount of cooking oil into the sink and tub to effectively seal the p traps temporarily and then smell around the base of the toilet to see if the smell is coming from there. This is a common problem and easily fixed see blogs below:

http://nationalbuildersupply.blogspot.com/2010/01/toilet-repair-102.html 

or

http://nationalbuildersupply.blogspot.com/2009/10/new-idea-for-replacing-wax-ring.html

As to your question about the vent problem, a clogged vent will cause water to be sucked out of the closest P trap (usually the bathtub) so that the vent can breathe, thus the localized smell. It sounds unlikely that the vent is the problem if you have had it unclogged although in extreme cold weather a vent can clog with ice and cause the same problem.
Lastly would be a broken drain pipe caused by the augering and can only be diagnosed with a camera or smoke test but the break in a drain line would not usually localized the smell to a single bathroom but should be apparent all over the house. I Hope these suggestions help. For further research on methane smells and the danger use the search function on my blog through either of the links above. Let me know what you find out.

Epilogue: Thank you so much Richard for your response. Our plumber came back today and jack hammered the foundation and ripped out the vanity. Well, they found a dead mouse, a huge stash of acorns and seeds, and the insulation had been made into the critter's bed. Along with this, came the critter's bathroom. They found a hole for pipes to the outside that had not been sealed up by the builders when the house was constructed that allowed animals to enter and make a home under the floor of the vanity. I can't imagine one little mouse making such a stench, but we are hoping this is it! Our plumber had a short scope and really examined all the pipes he could gain access to and could not find leaks. Keep your fingers crossed! And thanks so much again.

Thanks to this reader for bringing this one to me and helping me to think outside of the box (or maybe the septic tank). The problem with critters dying in your walls is that sometimes you just can’t get to them to remove the remains and stifle the smell. Unfortunately this means waiting for nature to take its course and reduce the remains to a non smelly condition. This means buying stock in Glade or Yankee Candle to manage to live with the smell.