There are various reasons why you could have a sewer gas smell within your home but, the most common causes are; Incorrectly installed plumbing systems  A broken vent line Dried drains no longer in use Toilet wax seal has gone bad  These are only a few of many reasons why you could have a sewer gas smell entering your house. There are many more, complex and difficult to detect. They are best left to good plumbers to fix. Nels plumbers are certified, and experts at what they do. No plumbing job is beyond fixing. Call Nels plumbers to get rid of that foul sewer smell in your home!