A leaking water heater is not something to ignore. If water extinguishes the pilot light on a gas heater, the danger of explosion is present along with the water damage. First determine where the water leak is occurring, so you can see if you are facing a DIY job or calling for an emergency plumber. If the emergency water relieve valve is leaking, turn off the water heater and turn on a hot water faucet in the house. When the tank is drained, follow the troubleshooting guide in the owner's manual. Call a plumber to replace the water heater.