For my problem, I posted some photos here: http://www.picturetrail.com/waterheater
Basically, as you could see in the photo (especially the 1st photo), you could see the water (the water stain) coming out of the plumber's putty thingy, so I'm not sure whether I could just caulk or use plumber's putty to just fill it?? Is this something that I could fix or DIY by myself? Or should I really consult with a plumber or professional?? According to the article above, I might have a defective valve, but it also could be high tank pressure (our neighborhood just had some seismic upgrade so it could be related).. How could I tell whether it's the valve problem or the high tank pressure problem? Thanks!