Back to Questions	I have a gas water heater and am on a public water system. My pressure relief valve leaks. I've changed it, but the problem still exists.  What can I do?	.
	This indicates a condition called thermal expansion.  When water is heated, it expands because of the air that is dissolved in it.  Most public water providers are installing meters with back-flow preventers.  This eliminates the capacity for expansion, causing the pressure to increase and push open the relief valve.  There are a couple of ways to handle this problem. The most common is to install a thermal expansion tank to absorb the pressure. If you need more help, go into Bill's Plumbing and ask one of their specialists, or email your question. One of Bill's specialists will get a prompt answer to you, often by the next day!