: My house is about 12 years old and over the past 6 weeks a strong septic odor has developed in the basement following drainage of large volumes of water (i.e. laundry, bathtub). There are no drainage problems, just the odor in the basement. We have capped an old drain for water softner. Can you help us determine cause of the odor and how to eliminate it.
Check for any open clean-out fittings on sewer or drainage piping.
Make sure that any infrequently used plumbing fixtures, (including floor drains) all have water in the traps.
Good Luck & Happy Holidays. e-plumber