gasleak
Is a leaking gas fitting something a non-professional should even attempt to fix?
Symptoms:
There is a slight off odor around the hot water system, after some experimentation of turning the gas off at the valve and waiting 30 minutes the smell disappears. Later opening up the valve again the smell returns.
It's a copper pipe with a tap valve.
Can I just use some Thread Seal Tape (plumbers tape)? After turning off the gas at the main.
Tighten the joint slightly.
Pipe threads are tapered - the PTFE thread tape (or pipe dope - I'm currently more of a fan of PTFE pipe dope than of PTFE thread tape, though I used to be a big fan of the tape as opposed to old-style dope) provides a seal for the "helical leak path" (the fact that the female threads are a bit sharper than the top of the male threads) and some lubricity for easier tightening.
A slow drip type leak is often just a 1/4 turn from not leaking.
If you take it apart, you need to clean off the remains of the old tape and apply new tape (one reason I now prefer the modern dope - you can just add a bit more, with no need to clean off the old, and you don't have all the tape shreds to deal with.) Excessive thickness of tape won't help the seal - more is not better.
It might be a small leak or several very small leaks. I had a leak in my Philadelphia home for years and had no clue. During remodel, I replaced the gas pipes (same appliances), and my gas bill unexpectedly went down by $50 for the summer months. A bubble test will not do. Obtain a real gas leak tester, and thoroughly and methodically test each joint.
Best Answer
I don't think it's as dire as all the comments are making it out to be. Some people are just afraid of gas, just like some people are afraid of anything involving electricity. If you think it's just a loose coupling, you can turn the gas off, unscrew the coupling, apply pipe dope (not tape) and re-attach the coupling and turn the gas back on. If it still smells you aren't any worse off than before minus a few bucks for the can of pipe dope.