What Causes a Water Heater to Leak?

If the water heater starts to leak, it is typically a sign of a more significant issue. Your water heater can leak from the top, bottom, or internally. Regardless of the leak location, it will require immediate attention to protect the water heater from further damage and even from bursting.

Here are the most common causes of water heater leaks.

Rust and corrosion

Water heater leaks are commonly caused by age and a lack of regular maintenance. Corrosion and rust have developed over the years and lead to leaks in two ways. 

The sacrificial anode rod hasn’t been replaced

Tank-style water heaters have at least one sacrificial anode rod, and large water heaters have anywhere from two to five rods. The purpose of these rods is to attract corrosive particles and prevent the tank’s lining from deteriorating. These rods contain aluminum-zinc alloy and magnesium on a steel core wire and must be checked for corrosion.

Scale build-up

The other reason why the water heater develops rust and corrosion is scale build-up. When hard water is heated in certain areas, it creates a calcium carbonate build-up called “scale.” The scale build-up creates an insulating effect at the bottom of the water heater tank and causes it to overheat. By doing so, the protective glass lining of the tank gradually melts, and the exposed steel begins to rust and deteriorate.

Increased tank pressure

While corrosion is a water heater’s number one enemy, increased water pressure is a close second. There are a few ways elevated tank pressure can cause leaks.

When heated, water expands. The process is called thermal expansion, and it means that water at 145 degrees will take up more space than the same volume of water heated to 125 degrees. If the water heater doesn’t have an expansion tank, leaks can quickly become a reality.

Another problem is the excessive water supply pressure. When the water pressure is too intense, it can cause damage to home appliances and even water heaters. To set the water supply pressure at the appropriate range, homeowners need a specialized regulator.

Finally, you might notice leaks from the water heater because the pressure relief valves have failed and should be replaced.

Water heater maintenance is essential

If the water heater is old and beyond repair, it’s time to invest in a new unit. But a leak here and there doesn’t mean you’re out of options.

Too much corrosion is not a good sign but flushing a water heater periodically can be immensely helpful. However, when dealing with water heater leaks, make sure to contact certified professionals to help repair and maintain the unit.

Trust MNS Plumbing, a licensed and friendly plumber in the Phoenix area, for all your gas water heaters, electric water heaters, and gas line installation and repair needs.