Is It Normal For Water Heater To Hiss: Find Out Now!

Debarghya Roy

Have you heard your water heater hiss? It’s an intriguing question – is this normal, or a cause for worry? The answer depends on what sound you hear and any other symptoms. Let’s explore why water heaters hiss, the dangers it poses, and what to do if you detect this issue.

Normally, a water heater shouldn’t make any hissing noises. But if you hear it, it could be a sign of a problem. One cause could be a leak in the tank, which can be caused by corrosion or damage. Hot water may seep out or steam escape from the tank.

Sediment buildup is another common cause. Minerals and debris can accumulate in the tank over time, causing popping or sizzling when the burner heats the water. This can also lead to overheating and tank failure.

Pressure-related issues can cause hissing too. If the pressure relief valve or drain valve isn’t working properly, excess pressure builds up and steam or hot water escapes through these valves.

If you hear your water heater hiss, it’s important to act quickly. Check for visible signs of leakage around the tank or valves. Leaks or tears require professional repair or replacement.

Flush out the tank, according to manufacturer instructions, to deal with sediment buildup. Drain some of the existing hot water, then refill to remove the sediment. Regular maintenance and flushing can help prolong the water heater’s lifespan and reduce the chances of hissing.

Understanding the causes of a hissing water heater

Is a hissing water heater normal? It could be. Common causes are sediment build-up and a faulty pressure relief valve. But, if the hissing is accompanied by sparks or sizzles, it’s an emergency. Contact a professional. High water temperature or pressure also lead to hissing. Sediment on a heating element could cause popping noises. Cold water entering a hot tank can create condensation and hissing too.

A red cap on the drain valve may indicate the water heater has had leaks or tears. So, if you see one during regular maintenance checks, consider replacing your water heater. Kevin Norris from Rheem Water Heaters states that a hissing sound could mean a fracture in the tank. If you hear it, act fast and have a professional inspect your water heater. Determine if the hiss is just a weird greeting or a sign of something worse.

Key Notes

  • It is normal for a water heater to make some noise, including a hissing sound.
  • The hissing sound is typically caused by the release of pressure through the temperature and pressure relief valve.
  • If the hissing sound is accompanied by other issues such as leaking or a decrease in hot water supply, it may indicate a problem that needs to be addressed.
  • Regular maintenance and inspection of the water heater can help prevent potential issues and ensure its proper functioning.
  • If you are unsure about the source or severity of the hissing sound, it is recommended to contact a professional plumber to assess and resolve the issue.

Assessing the severity of the issue

When you hear your water heater hiss, it’s important to assess the severity of the issue. This will help you identify if the sound is normal or if there is a potential danger.

Consider these factors to assess the severity:

  1. Normal: A hissing sound when hot water is running, especially after not using it for some time.
  2. Minor Issue: Hissing accompanied by small water bubbles or sizzling sounds when the heater is operating.
  3. Medium Issue: Continuous hissing noise, visible leaks on the tank, or red caps indicating a tank leak.
  4. Major Issue: Hissing accompanied by sparks or popping noises, excessive buildup of sediment causing overheating and pressure issues.
  5. Immediate Attention: Hissing sounds along with large amounts of water leaking from the tank, tears or fractures in the tank, or extremely high water temperatures.

If you notice minor signs like small bubbles or sizzling noises, there may not be an immediate cause for concern. But it’s still best to address these issues as they can lead to bigger problems.

For medium issues, contact a professional plumber for assistance. They can diagnose and repair any damage.

In cases of major issues, turn off the heating element and water supply to prevent further damage until a professional can assess and repair the heater.

To sum it up, assess the severity of a hissing water heater to decide if it needs minor maintenance or immediate professional attention. Regular maintenance and prompt repairs can help extend the lifespan of your water heater and prevent further damage or safety hazards. If in doubt, always consult a professional plumber for advice and assistance. Don’t worry, a hissing water heater isn’t trying to audition for a snake-charming gig!

Steps to take if your water heater is hissing

If your water heater is hissing, it’s not a reason to panic. But it’s important to take steps to solve the issue and prevent potential dangers or damage. Here’s a simple 5-step guide:

  1. Shut off the power. Turn off the power supply to the water heater. This will ensure your safety while you inspect and fix the issue.
  2. Check for leaks. Carefully look for any visible signs of leaks or tears in the tank. A leaking tank could lead to worse problems if ignored, so it’s essential to find any issues early.
  3. Test the pressure relief valve. The pressure relief valve is key in maintaining proper water pressure inside the tank. Try it by lifting its lever and releasing it. If it hisses, or if there’s excessive water discharge, it may need professional attention.
  4. Flush out sediment build-up. Over time, sediment can build up in the bottom of your water heater tank, causing hissing sounds and reducing efficiency. To address this, attach a hose to the drain valve and let some cold water flow for a few minutes until clear.
  5. Get professional help. If you’ve followed all these steps and your water heater is still hissing, get a pro. A licensed plumber will assess the issue, determine the cause, and suggest repairs or replacements if needed.

To prevent hissing, here are more tips:

  • Inspect your water heater for wear or damage regularly.
  • Keep proper temperature settings and don’t go too hot.
  • Monitor your hot water usage and look out for sudden spikes.
  • Install a water softener if you have hard water – mineral buildup can cause hissing.
  • Consider replacing an old or faulty water heater with a new, more efficient one.

Do these things and take action when you hear hissing to keep your water heater and home drama-free.

Preventive measures for avoiding a hissing water heater

Is it normal for a water heater to hiss? Well, if your water heater sounds like it’s auditioning for a horror movie, you may need to call a plumber…or an exorcist! To prevent such issues, there are some steps you can take.

  1. Schedule regular inspections and maintenance by a professional plumber to identify minor problems before they become major.
  2. Test the pressure relief valve regularly to ensure it functions properly, releasing any excess pressure that could lead to hissing sounds and leaks.
  3. Flush the tank to remove sediment buildup and keep your system running smoothly.
  4. Adjust the water temperature settings within recommended limits to prevent high pressure from building in the tank.
  5. Check and replace the anode rod when necessary to prevent corrosion and potential hissing noises.
  6. Monitor the water pressure with a pressure gauge to keep it within acceptable limits.
  7. Also, if you notice a red cap on the drain valve, contact a plumber immediately as this could indicate excess pressure in the tank.

In addition, insulate the water heater tank to reduce heat loss, reduce water usage during peak times, and consider replacing an older model with a newer, more efficient one. Implementing these preventive measures and suggestions can help keep your water heater running smoothly and without any hissing.

Frequently Asked Questions

Q: Is it normal for a water heater to hiss?

A: No, a hissing sound coming from a water heater is not normal and should be addressed.

Q: Is a hissing water heater dangerous?

A: Yes, a hissing water heater can be dangerous as it may indicate a leak or high water pressure, which can potentially lead to damage or injury.

Q: What should I do if my water heater is hissing?

A: If your water heater is hissing, it’s important to turn off the gas or electricity supply and contact a professional plumber for inspection and repair.

Q: What are the common causes of a hissing water heater?

A: Hissing noises can be caused by issues such as a leaking relief valve, sediment buildup in the tank, high water pressure, or a faulty heating element.

Q: Can a hissing water heater be fixed, or do I need a replacement?

A: Depending on the cause and severity of the issue, a hissing water heater may be repairable. A professional plumber can assess the situation and advise whether a repair or replacement is necessary.

Q: Can I try to fix a hissing water heater on my own?

A: It is not recommended to try fixing a hissing water heater on your own, as it involves potential risks and requires specialized knowledge. It is best to contact a professional plumber for assistance.


Hissing from a water heater is not normal. It could indicate various problems, like a tank leak, faulty drain valve, or overheating. If you hear hissing, take action!

Sediment buildup in the tank may cause it to overheat and lead to hissing. Flushing the tank could help, but it’s better to get help from a professional.

A faulty pressure relief valve could also be the culprit. If this is the case, contact a professional to inspect and replace it.

Leaks or tears in the tank, or hot water temperature fluctuations, might indicate a more serious issue. Call a professional for repair or replacement.

For optimal performance and longevity of the hot water system, flush the tank annually and check for any signs of leaks and unusual sounds.

About the author

Debarghya Roy: A heating systems author, Passionate about energy efficiency and sustainability, Sharing insights and empowering readers through informative blog articles.