When your basement smells like rotten eggs: weird facts about wastewater mishaps

That’s funny, I actually thought my drains were the culprit for weeks, but it turned out to be a vent stack issue too. The smell would come and go, which made it even harder to track down. I climbed up into the attic and found a squirrel nest blocking half the pipe - never thought I’d be evicting wildlife just to get rid of that sulfur stench. Sometimes I wonder if these old houses are just held together by luck and random critters...

Sometimes I wonder if these old houses are just held together by luck and random critters...

- You’re not wrong - old vent stacks are magnets for nests and debris.
- That “come and go” smell is classic for partial vent blockages.
- Good call checking the attic. Most folks never think to look up.
- If you ever get that sulfur smell again, check for slow drains too - sometimes it’s a combo of issues.
- Wildlife in plumbing is more common than people realize... seen raccoons do worse!

Funny how often people forget that plumbing vents even exist, let alone that they can get blocked up by all sorts of stuff. I’ve lost count of the times I’ve found bird nests or even just a wad of leaves causing those “mystery” smells. One thing I’d add: sometimes it’s not just the vent stack - if you’ve got old cast iron lines, cracks or loose joints can let sewer gases seep in, especially after a heavy rain.

That rotten egg smell is usually hydrogen sulfide from sewer gas, but if it’s only in one spot (like the basement), it might be worth checking any unused floor drains. The traps can dry out and let gases up into the house. Just pouring a little water down them every month or so keeps that barrier in place.

And yeah, wildlife... Once found a squirrel skeleton in a vent pipe. Still not sure how it got there, but it definitely explained the smell.

You’re not kidding about those floor drains. I learned the hard way after a long vacation - came home to a basement that smelled like a science experiment gone wrong. A cup of water down the drain would’ve saved me hours of sniffing around and Googling “why does my house smell like eggs.” Also, I swear, vent pipes are like Airbnb for critters. I once found a wasp nest in mine... not as dramatic as a squirrel skeleton, but still gross. Sometimes I wonder if plumbers should charge extra for wildlife removal.

I hear you on the vent pipes - last year I had a bird’s nest blocking mine and the whole house started gurgling like a haunted fish tank. Ever tried those little mesh caps? They help, but I swear, squirrels treat them like an IQ test. Anyone else ever had to fish out something weird from a drain or vent?