In one of our bathrooms, we have a sewer gas odor. It is coming from around
the commode, not from the shower, sinks or tub. I am guessing it is
probably a bad wax ring, but I am not able to tackle the job myself.

I called a plumber, and he told me they had to run a 'smoke test' to
determine the problem. He said I had to notify the fire department they
were going to run the smoke test, that is the law (????). I asked how much
that cost. "$300"!!!!

Then I asked how much to change the wax ring without the smoke test. He
said they won't do that unless they first run the smoke test.

I think it's a rip off. Surely, it wouldn't take more than an hour to
replace the wax ring, and even at an inflated price, that should not be over
$100.

Question: Is this a normal procedure, or a rip off?

Thanks for your advice.

Bob-tx