4. Add Water to Your Basement Floor Drain: The floor drain includes a trap to prevent sewer gases from backing up into your home. When plumbing systems aren't being used over an extended period of time, the water in the trap evaporates, resulting in unpleasant and unhealthy sewer gases entering the home. We recommend pouring water down the drain to fill the trap before going on vacation to ensure the trap water doesn't evaporate while you're away.
Source: Carson Dunlop