"peter" wrote in message
news:Oz0tg.5732$pB.4088@trnddc06...
When I stand right next to the water heater, I smell a little bit of gas
at certain height. If I move to 1 foot away, I no longer can smell it.

See this photo:
http://www.smugmug.com/gallery/990857
The red ellipse shows where I smell the gas. I smell some at lower spots,
but it's not continuous, meaning when I go lower, I don't smell it, then I
smell it, ...

I assume it has been like this during the last year, and there is no
cumulation of natural gas (like I said, only can smell it within a foot).
So I wonder, is it normal for a water heater with pilot light to emit some
natural gas odor, or should I try to seal all the pipe joints?
Your question is pretty dangerous, remember that this is a public forum and
therefore we can't tell what your situation and what your intelligence level
really is, so a question involving highly flammable gas typically is
answered very conservatively.

As to whether it is normal or not, it can yes. I have spoken with people
who do home calls and people who do training for PSE (Puget Sound Energy)
and on certain gas water heaters it is normal to smell gas around the burner
control knob. But your circle doesn't indicate that location so in my mind
you should perhaps ask your gas supplier if they can verify the installation
for you. It's what I did when I smelled gas in and around my gas control
box. No reason to risk sending your water heater into low orbit.