My boyfriend and I just bought a house, which is a major fixer. The original floor (downstairs) was built in 1919 and since added onto without permits. Unfortunately, the rest of the house looks like someone pulled up with a pick-up full of miscellaneous materials and said, "Well......we're going to build a second floor and just make it work with what we've got."

The upstairs bathroom has a strong sewage smell that comes and goes. It seems to get stronger when we run the washing machine. It does not appear there is proper ventilation to the bathroom... no vent pipes and also no windows/skylights. I am concerned about it.

We do have a crawlspace under the house, as the bathroom is supported by a perimeter foundation. We are on city sewer, which eliminates possible septic issues. We have only lived in the home a couple weeks, so I am not sure if this is a new or old issue. The bathroom gets used every day and very regularly. We are a family of 5 with one bathroom right now.

As many people do, we will be making any necessary repairs ourselves (hopefully). Where do I need to look? What do I need to look for? And how can I fix it? Is there a good online reference that would illustrate step-by-step the possible repairs I will need to do? Also, what kind of health risks are we subjected to if there are sewage gases seeping back into the house?

I am hoping this issue fixed before the rains come, which I suspect will make the odor even stronger if it is not corrected by then! Thank you for your help!

There obviously could be many reasons (I am not a plumber or an expert in this area) but on several occasions when the main possibilities checked out I found that the reason for the smells in the bathroom was that the seal at the floor where the toilet pedestal sits had broken. Worth checking out...

Hope it helps,
Stringer

Stringer gave you the most logical place to start. A ruptured wax seal would allow sewer gas to blow back as the washer discharged. Any gurgling from any of the drains? Back to you, tom