Why Is My Water Heater Hissing? Here's What You Need to Know

 Have you noticed a strange hissing sound coming from your water heater and wondered if it's something to worry about? You're not alone. A hissing sound can be unsettling, especially when it's coming from an appliance you use every day. The good news is that this sound isn't always a sign of disaster, but it's definitely something you shouldn't ignore.

Sediment accumulation 

One of the most common causes of a hissing water heater is sediment buildup. As time passes, minerals from hard water can accumulate at the bottom of the tank. When the heating element warms up, the water trapped in this sediment layer can vaporize, producing the characteristic hissing sound. It's like pouring water into a hot pan: it sizzles right away. If left untreated, this can reduce the efficiency of your water heater and eventually damage your tank.

Water leak on the heating element

Another possible cause is a minor leak within the tank. If the water drips onto a hot surface, such as the electric heating element or gas burner, it can produce a hissing or sizzling sound. In this case, the noise may be more intermittent, depending on the location and size of the leak. It is essential to check the base of the water heater for moisture, rust, or stagnant water: clear signs of a leak.

High Pressure or Temperature Settings

If your water heater is set too high or if pressure builds up in the tank, the temperature and pressure (T&P) safety valve may activate. When this happens, it releases small amounts of steam or water to prevent the tank from overpressurizing. This release is often accompanied by a hissing sound. Although this safety feature works properly, frequent activation could indicate a setting that needs adjustment or a faulty valve.

What to do?

If your water heater is hissing, start by checking the thermostat setting; it should generally be around 49°C. Inspect the tank for signs of leaks or corrosion. If all goes well, try flushing the tank to remove sediment (an often overlooked annual maintenance). However, if you have any concerns or notice other warning signs such as discolored water, fluctuating temperatures, or standing water, it is a good idea to call a qualified plumber.

Bottom Line

A hissing water heater can be a minor maintenance issue or a sign that something more serious is about to happen. Catching and fixing the problem early can save you from costly repairs and help extend the life of your appliance.

Call Emergency Plumber in Dudley. We are available around the clock.