Water Heater Problems: 5 Potential Causes of Hissing Noises

If your water heater is making hissing noises, it’s vital to determine its cause. Otherwise, you may enact repairs on the wrong parts while its compromised components continue to deteriorate. Once you can figure out the source of damage, you can determine if you’ll need a professional technician or if minor repairs will do.

In this article, we’ll share five potential causes of your hissing water heater.

1. High Temperature

A hissing sound coming from your water could be a build-up of pressure. This occurs if the Temperature and pressure valve automatically opens to release pressure due to higher heat levels. Unfortunately, a broken T&P valve can be dangerous for your unit, causing the pressure build-up to cause leaks from other openings.

2. Condensation

With more heat also comes the material transformation of condensation. This occurs when condensation builds up outside the tank with the water heater’s hot parts. This leads to a sharp hissing sound as they collide. Since condensation naturally occurs in the environment, it shouldn’t be a cause of concern for broken water heater parts.

3. Sediment Build Up

The condition of water you receive from the tap will vary, depending on your water provider and general location. Some regions are more prone to hard water containing minerals like calcium, magnesium, and more. These aren’t inherently harmful to humans, but high amounts of them can lead to digestive problems and complications to your plumbing.

The sediments from hard water directly enter your water heater tank, with the water being flushed out while its residue stays at the bottom of the hot water tank. Over time, these minerals can trap water bubbles, causing them to boil into steam, causing a hissing noise. If your water heater is hissing due to steam, you may want to clean your water heater and add a filter to your system.

4. Water Heater Leaks

Besides the reactions occurring inside your water heater, the cause of hissing can also be due to a leak. Similar to condensation from surroundings, a leak in your tank’s different components will lead to a hissing noise due to a temperature difference. As water flows through an opening down a high-temperature surface, a hissing sound will cause it to boil and sizzle, causing the hissing noise.

5. Age

Sometimes, the unavoidable deterioration of your water tank isn’t due to any one cause. This is because your entire unit may be failing completely. While it’s possible to purchase replacements on the more damaged components, you’ll still need to replace them all eventually. Even then, you would have spent a lot of money on replacements when you could have bought a new one instead.


You should never overlook the current condition of your water heater, especially if it has been going on for weeks. Even if your water heater is operating normally, these disturbances can be a sign of an inevitable appliance failure. By then, it would be too late to perform simple repairs. For this reason, you should always contact your local heating technicians to assess your home’s different utilities.

At Legacy Heating and Cooling, we give our clients comprehensive and cost-effective HVAC products with our decades of experience. This is why getting our team of qualified technicians to inspect and treat your problems is the best course of action. If you need to repair your home’s hot water tank or heater in Edmonton, contact us at 780-900-3315 today!

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