If Hank Hill uses propane for his stove, dryer and heat, then why don't we see a propane tank sitting somewhere on the property?
Edit: Maybe his subdivision has it piped to them? But I honestly don't believe that everyone on Rainey Street agreed to pay for it when natural gas is a lot more affordable.
I have never seen one in the garage, and in the episode where Dale digs a tunnel under Hank's house, he doesn't have a basement and it doesn't look like there is one in his crawlspace. But I suppose the crawlspace would be the last possible place it could be.