We moved into this house last February. The house uses a septic tank which is located itneh front yard. Teh lot slpoes downwards towards the back. As a result, the basement bath is located lower than the septic tank.
In the last 2 or 3 months the smell has become unbearable. We rarely use the bathroom as a result.
We've never noticed slow drainage from the sink or shower. And the water level in the toilet is consistently at a normal level.
Could the smell have something to do with the trap seal? How can we check?

"the basement bath is located lower than the septic tank."

One of the first things a plumber learns is that sh*t won't flow up hill. How did you manage this? Do you have a holding tank and a sewage pump in your basement? Regards, Tom

Hi,
If you have just started noticing the smell, and if it hasn't been there the whole time you have been moved into the house, maybe the septic tank needs pumping.
I would call someone who pumps septics, ask the cost, and ask them about pumping it out. Could be that the water level in septic has risen, and is not draining into your septic field as it should.
I do wish you the best of luck.

We got bored yesterday, noticed the tank bolts were rusted and leaking so we replaced them. While we were doing that, replaced the wax seal on the bowl too.

speedball1- I don't see a pump anywhere. Makes sense there would be one, but itmust be hiding. Is it possible it was buried when the house was built?

fredg - If the septic tank needs maintenance, why don't I smell it in all the bathrooms?

"We went ahead and replaced the wax seal on the bowl too."

Let us know if that helped the smell. Cheers, Tom

I'm ready to call a specialist.

It's impossible to track a smell if you're not there to sniff it down. Drains, toilets, and open vents cause most bad odors but we can't help much. We can only point you towards the most likely spot. Good luck, Tom