[jgwalton]

I have a two story home about 3 years old. The problem started about a year ago with the upstairs toilets. Then included the downstairs toilet. It is a septic smell . The toilets all gurgle and burp when flushed which of course lets the smell burp in. I've snaked all the vents today and find no cloggs.There is a unfinished shower on the second floor that I'm sure that the trap is dry. But no smell through drain. There is also a unfinished shower and bath group (toilet, sink ) in the garage which is below the first floor plumbing. These traps are dry also, but again no smell. Smell only from the toilets? What to do next?

[Flickit]

I have a two story home about 3 years old. The problem started about a year ago with the upstairs toilets. Then included the downstairs toilet. It is a septic smell . The toilets all gurgle and burp when flushed which of course lets the smell burp in. I've snaked all the vents today and find no cloggs.There is a unfinished shower on the second floor that I'm sure that the trap is dry. but no smell through drain. There is also a unfinished shower and bath group (toilet, sink ) in the garage which is below the first floor plumbing. These traps are dry also, but again no smell. Smell only from the toilets? What to do next?

... the traps been dry? Sounds like there may be a connection between the time it started and possibly the time these other fixtures were left unused. Might be worth a try to fill up these unused fixtures with water for at least a few minutes and see if there is any improvement. That you get no smell from the dry vents but from the toilet doesn't conclude the problem is not at the unused fixtures... only that the odor is not getting into the vent and outside where it belongs.

[speedball1]

I have a two story home about 3 years old. The problem started about a year ago with the upstairs toilets. Then included the downstairs toilet. It is a septic smell . The toilets all gurgle and burp when flushed which of course lets the smell burp in. I've snaked all the vents today and find no cloggs.There is a unfinished shower on the second floor that I'm sure that the trap is dry. but no smell through drain. There is also a unfinished shower and bath group (toilet, sink ) in the garage which is below the first floor plumbing. These traps are dry also, but again no smell. Smell only from the toilets? What to do next?

Fill the unused traps with motor oil to prevent evaporation and forget them. They will vent sewer gas every time drainage discharges if you leave them open.
Are you on city sewer or septic tank? The "burp" tells me you have a partial blockage in the line somewhere pushing sewer gas back up the line and burping out your toilet. Snake the sewer line and if you're on a septic tank then open it up to see if it's full and the drain field is draining as it should.
Good luck, Tom