Definitely agree on not jumping straight to demo—seen too many folks tear up half their basement for what turned out to be a dry trap or a loose cleanout plug. One thing I’d add: check any unused bathrooms, especially in basements or guest rooms. Those toilet traps can dry out too, and people forget about them for months.
Also, don’t overlook the vent stack on the roof. Birds love to nest in those, and a blocked vent can cause all sorts of weird pressure issues and smells inside. Not saying it’s common, but I’ve found more than one dead squirrel up there over the years...
On the mineral oil tip—works well, but if you’re in an area with a lot of temperature swings, you might need to top it off more often than you’d expect. And yeah, vegetable oil just turns into a sticky mess.
Bottom line: most “sewer gas” calls I get are solved with a flashlight and a bucket of water. The real problems are rare, but when they happen... you’ll know.
Had a similar situation last winter—got a call about a “horrible sewer smell” in one of my rentals. Tenant was convinced there was a broken pipe under the slab. Turned out, the guest bathroom hadn’t been used in months and the toilet trap was bone dry. Quick flush and the smell disappeared. It’s wild how often it’s something simple like that.
I’ve also run into the vent stack issue, but honestly, I see more problems with critters than actual blockages. Once found a bird’s nest and a tennis ball up there... not sure how that even happens. I do agree on mineral oil for floor drains, but I’ve noticed it evaporates faster than you’d think when the furnace is running a lot.
Demo should always be the last resort. Nine times out of ten, it’s just a dry trap or loose fitting somewhere. Saves a lot of headaches (and money) to check the basics first.
I get where you’re coming from about checking the basics first, but I’ve gotta say, sometimes it’s not just a dry trap or a loose fitting. When we moved in, our basement had that classic rotten egg smell and I went through all the usual suspects—traps, drains, even poured mineral oil like you mentioned. Turned out, there was a tiny crack in the main sewer line under the slab. Not saying demo should be your first move, but sometimes you do have to dig a little deeper (literally). Guess it’s just one of those things where you hope for the easy fix but can’t rule out the bigger stuff.
Honestly, I get the urge to jump to worst-case scenarios, but in my experience, it’s still rare for a main line crack to be the culprit. Nine times out of ten, it’s something simple—bad wax ring, dried out cleanout, or even a forgotten floor drain. Not saying you’re wrong, just that demo is usually the last resort for a reason. Sometimes the stink is just a stubborn one, though...
Nine times out of ten, it’s something simple—bad wax ring, dried out cleanout, or even a forgotten floor drain.
- True, but I’ve seen main line cracks more than folks think, especially in older homes with shifting foundations.
- Don’t rule out a partial collapse or root intrusion if the smell lingers after the usual fixes.
- Sometimes, a camera inspection saves a lot of guesswork—beats tearing up the floor without a clear target.
- Not every stubborn stink is a simple fix... sometimes it’s hiding in the walls or slab.