The gang over at MythBusterswondered what would happen if you raised the PSI of a water heater. So they built a small house using building California standards, just to see exactly what would explode and how a house would hold up if a water heater exploded.
Check out this video yourself to see what happened. Mythbuster Water Heater Test
Then as a follow up experiment they took a larger water heater, raised the PSI to double before it launched. They also placed explosive shock stickers by the site to see what type of explosion it would register. Take a look at the resultsMythbuster Rocket Water Heater
The results are amazing. Its scary just what a water heater can do to a house if the PSI raises more then it should.