The answer is, it’s usually not dangerous because modern gas water heaters have valves that turn off the gas if the pilot light goes out. That means you aren’t likely to be gassed or have an explosion. Back in the 1930s, gas water heaters tended to explode because of a lack of valves to relieve both pressure and temperature.
Today we have what’s called a thermocouple, the tip of which is located above the flame of the pilot light and generates a voltage that keeps the gas valve open when it senses that your pilot light is on. If dust builds up on the thermocouple or it’s bent out of shape, it can lose its ability to do its job of turning off the gas when the pilot light goes out. This could mean major trouble.
Another dangerous situation occurs when today’s gas water heaters are located in enclosed spaces where there isn’t much airflow. Without combustible air, the pilot light will go out. It needs air to burn. In that case, carbon monoxide can build up and leak into other parts of the house or lead to an explosion.
So, what do you do if the pilot light keeps going out? Call Paul the Plumber who can detect the reason and make the repairs needed to keep you safe and make sure you have the hot water you need when you want it.