Sewer gas smell in basement is detectable, far from overwhelming.
I ran a search, considered numerous possibilities (dry trap, open clean-out in floor drain, etc). None seem to fit. Sniffed the bsmt. floor drain particularly carefully as sump, washer, and AC drain there: no odor.
I gotta track it down.
100% safe to pour a pint or so of laundry bleach in each drain?
" ... and the bees made honey in the lion's head." - from "If I Had My Way", Blind Willie Johnson