I have a bad sewage smell when flushing all toilets in the house. The house was built 2 years ago on a slab. The toilets flush normally, water levels are good, only once did we have a clog which was remedied by a normal plunger. Each time we flush we smell the sewage. No smell comes from other pipes in the house only the toilets. Any suggestions would be great, I am about to call a plumber. I am suspect of the builder and the plumber they hired when building the home to begin with.

I have a bad sewage smell when flushing all toilets in the house. the house was built 2 years ago on a slab. the toilets flush normally, water levels are good, only once did we have a clog which was remedied by a normal plunger. Each time we flush we smell the sewage. No smell comes from other pipes in the house only the toilets. Any suggestions would be great, i am about to call a plumber. I am suspect of the builder and the plumber they hired when building the home to begin with.
The smell is coming back up from your sewer pipe, More than likely the air trap isn't working or is too shallow.

It works the same as a u-bend on your sink. Water sits in the U of the bend and prevents smells from getting back up the pipe.

I'm not a plumber but would suggest that if you have one coming that is probably what he should be looking for. If its all the toilets then it will be a main air trap nearer the sewer pipe.

Nicnet

If you had a lowered level in your bowl I would go along with Nicnets answer. However, a normal bowl level means a normal trap level. Which leaves a wax ring that's ruptured and every time you flush it let's out a puff of sewer gas. Is one toilet worse the others? Is the smell worse in one area then in another? Let me know, Tom