Sewer Gas smell and bubbling toilet?

[ChrisRice]

You all have been helpful in the past, so ill try again

This just started happening recently...

I have a laundry room /bathroom in my basement.

Recently (as in the last three Sundays..laundry day) when the washer drains the first time there's a sewer gas odor in the basement. The odor goes away relatively quickly and does not return through 3-4 more loads of laundry. The toilet has also started bubbling as the washer drains and if you flush the toilet it is VERY slow to drain. I think its a bubble vs a gurgle, I'm not sure how to tell the difference.

The sink and tub in that bathroom seem to drain just fine, though I haven't run an excess of water down them while this is occurring (just turned the water on for a minute or so).

The toilet remains slow for 12ish hours, meaning I've gone back down a few hours after laundry and it's still slow, but the next morning it's always fine.

I haven't altered anything and like I said it just started happening recently.

Venting? A clog somewhere? Thoughts?

Thanks in advance!

[Tom Sawyer]

If you are on a septic tank I suspect you need to get the tank pumped and have them check the inlet baffle and possibly the D box at the same time.

[ChrisRice]

If you are on a septic tank I suspect you need to get the tank pumped and have them check the inlet baffle and possibly the D box at the same time.

No septic, guess that'd been helpful first

[cacher_chick]

I would speculate that you have a partial clog in your main building drain going out to the city sewer.

[jadnashua]

Because the WM dumps lots of water quickly because it has a pump. Once the pipe gets full from the partical clog back to where the toilet is, the toilet can't dump its water and waste into the mostly full pipe. If it can't move fast enough, it won't empty. Higher stuff from above can partially fill the pipe.