I'm experiencing strong "sewer odors" coming from one of the basement drains. This is an old house (meaning the basement floor drains don't have an elbow bend and instead run straight down / there is no p-trap), but the strong odor is only present at one of three drains--which happens to be right by the furnace.
The rest of the plumbing in the house is new (just over 1 year), and the smell hasn't been an issue until the past month or so. Temperatures are still in the 30-50s range.
I'd gotten some "septic helper" at Home Depot, and was looking at ordering some active enzymes, but was not sure if they'd remain in the area long enough, or would be quickly whisked through.
Pouring water into the drain helps a little, but it's a daily exercise to even keep pace.
Basically, I'm not sure what to do to treat the root cause of the issue, and keep the odors from making me gag.
Any help would be appreciated!