Like any mechanical device, water heaters can malfunction or be used incorrectly. As a result, they might overheat and explode or catch fire. According to the National Fire Protection Association (NFPA), 5,200 residential water heaters caught fire or exploded in 2016. That’s an average of 11 fires per day. Fortunately, these incidents are rare and can be largely prevented by taking simple precautions and replacing your water heater if it’s past its expiration date. Whether you live in a small home or apartment, renting or planning to buy — your risk factors as well as potential mitigation measures — differ based on your living situation. The good news is that no matter what type of home you live in, water heaters are relatively affordable and easy to install.
Why Do Water Heaters Explode?
Water heaters are designed to last for about 10 years and then be replaced. However, many people keep using the same tank for longer, either because they don’t know when it expires or because replacement is too expensive. A water heater that is old, keeps running without adequate cooling, or isn’t installed or maintained properly is at risk of exploding or catching fire. Many types of water heaters can explode for the same reasons, including:
- The temperature of the water is too high (overheating).
- The water heater is not properly vented (lacks airflow).
- The gas or electrical wiring to the water heater is faulty.
- There is an electrical short or arc inside the water heater due to rust or other build-up.
- The water heater uses more energy than it can handle (for instance, it’s not sized correctly for the household’s needs).
How to prevent water heater explosions
Keep your water heater clean – If your water heater is more than 10 years old, get a new one. It’s not worth the risk: an older model will not only cost you more to run but also be more likely to malfunction and result in an explosion. When cleaning your water heater, follow these rules:
- Never use a net, broom or other cleaning tool to remove debris from the tank. You could damage the tank or pipes.
- Never use a device that injects water into the tank to clean it. The water could be contaminated and cause an electrical short.
- Wear gloves and eye protection when cleaning the tank to prevent injury from sharp debris.
- Never put cleaning chemicals inside the water heater. They could corrode the inside of the tank and cause an electrical short.
- Avoid leaving any loose parts in the tank (like the drain plug or gas line). They could clog the drain and cause the tank to overheat.
Boiler explosions in particular
When it comes to water heater explosions, it’s the natural gas ones that cause the most damage. If your home uses gas-fired water heaters, be extra careful and make sure you have an expert check for dangerous leaks once a year. Remember that a leak that goes unnoticed for too long can cause a major explosion. You should also have the gas line to your water heater checked once a year by a professional, even if there are no outward signs of corrosion. A gas water heater should be replaced after 10 years of use.
Shower and sink pipe burns
A high temperature in your water is one of the most common causes of water heater explosions. When your water is too hot, it can cause scalding and burns, especially in showers. If you have young children or elderly people living in your home, keep the water temperature between 95 and 110 degrees Fahrenheit. This will prevent scalding and burns, and also save you money on your energy bill.
Dishwasher and drainpipe fires
If your dishwasher is not vented properly, excess water can back up into your sink or tub. This can cause a flood, clog your plumbing, and even cause a fire in the worst case scenario. Always make sure your dishwasher is vented appropriately. Similarly, if water is not flowing freely from your drains, it can build up in your pipes and increase the risk of a fire. Make sure your drains are clean and clear, and take care when using a garbage disposal.
Most water heater explosions occur due to overheating, which could be caused by improper installation, lack of maintenance, or usage in excess of the capacity of the appliance. When buying a new water heater, make sure to get one that’s properly sized for your household’s needs. Also, consider replacing your water heater whenever it’s 10 years old — not only will you save money on energy bills but also greatly reduce the risk of an explosion.