Why Is My Water Heater Making Noise? 8 Common Causes and How to Fix Them

30 May 2025

General

If you’re a homeowner dealing with strange noises from your hot water heater, it’s usually a sign that something needs attention. Whether you live in a large suburban home or a downtown condo, water heater noises can pose safety risks if ignored.

At Plomberie Pro-Drain, we know how quickly minor issues can turn into costly repairs. That’s why we offer fast, professional diagnostics and long-lasting solutions for all types of water heater issues. In this article, we’ll break down the most common causes of water heater noise and explain the safest ways to resolve them.

8 Common Water Heater Noises in Homes

Here are the most frequent culprits behind a noisy water heater, and what they could mean for your home’s plumbing system:

1. Excessive Sediment Buildup in the Water Heater Tank

In many Canadian homes, particularly those with hard water, sediment buildup is the leading cause of popping or crackling noises in both gas and electric water heaters. Caused by mineral deposits like calcium and magnesium settling in the hot water tank, this buildup can reduce water flow, cause overheating or excess pressure, and lead to side effects like brown water, water stains, and a diminished hot water supply.

Solution

  • Perform regular flushing of the tank
  • Install a water softener or water purification system to prevent mineral accumulation
  • Schedule annual maintenance to prevent buildup over time

2. Loose Heating Element (Electric Models)

In homes with electric water heaters, a loose heating element is a common cause of vibration and buzzing sounds during heating cycles. This issue often results in a persistent humming noise, typically caused by wear, poor installation, or internal movement of the element. If left unchecked, it can loosen surrounding pipes or cause additional strain on internal components.

Solution

3. Water Pressure Surges & Water Hammers

Sudden spikes in water pressure can cause hammering sounds or tapping noises, especially when valves close abruptly. These pressure surges can damage pipes, outlet valves, or inlet connections, and are particularly common in older homes or those without a pressure-reducing valve. If your T&P valve discharges frequently, it can be a sign of dangerously excessive pressure in the system.

Solution

  • Install a pressure-reducing valve to stabilize water pressure
  • Add a water hammer arrestor to absorb shockwaves from fast-closing fixtures
  • Monitor for potential water pressure issues

4. Thermal Expansion in Closed Systems

As hot water expands, homes with closed-loop plumbing systems often experience groaning or creaking noises coming from the tank due to excess pressure. This is especially common in urban homes where the expanding water has nowhere to go. Over time, the added stress can affect cold water inlet pipes, non-heat trap nipples, and loose pipe straps, potentially leading to leaks, moisture buildup, or even water damage.

Solution

  • Install a thermal expansion tank to provide space for expanding water
  • Ask a professional plumber to inspect the water supply lines and tank pressure

5. Limescale on Heating Elements

Over time, limescale can build up on electric heating elements, particularly in homes with alkaline water. This often leads to sizzling sounds or high-pitched noises during heating cycles. If left untreated, it can damage the elements, resulting in costly repairs or even complete system failure.

Solution

  • Descale with vinegar or a descaling product
  • Replace damaged elements if scaling is severe
  • Use routine maintenance to extend the heater’s lifespan

6. Loose Parts, Pipes, or Valves

Noises in water heaters can also stem from loose pipe straps, brackets, or valves vibrating during operation, especially in older storage water heaters. These issues often produce clanking, rattling, or banging sounds when the unit heats up and can indicate wear on components like the outlet valves, gas lines, or even the anode rod.

Solution

7. Clogged or Noisy Drain Valve

A drain valve clogged by sediment can produce gurgling sounds and lead to slow draining during routine maintenance. This is often due to a buildup along tank floors or excessive sediment accumulation, which can result in backflow, a blocked floor drain, or delayed flushing cycles.

Solution

  • Flush the heater to clear the drain valve
  • Replace faulty valves to prevent restricted water flow

8. Thermostat Malfunction or Irregular Heating

A faulty thermostat can cause inconsistent heating cycles, leading to knocking or boiling sounds as the system overheats. This issue affects both gas-powered water heaters and electric models, often resulting in steam, bubbles, or noise at the hot water outlet. It can also cause the unit to reheat excessively, driving up your energy bills over time.

Solution

  • Test and reset the thermostat via the access panel
  • Replace the thermostat if symptoms persist

When Does a Hot Water Heater Need to Be Replaced?

Is a Noisy Water Heater Dangerous?

It can be. While some noise is normal, loud popping, hammering, or boiling sounds may signal unsafe pressure levels, water flow restriction, or even the risk of a tank rupture. In gas water heaters, noise could also point to burner issues or poor ventilation. Always have persistent or unusual sounds evaluated by a professional to avoid potential damage or safety hazards.

Contact 24/7 Professional Plumbing Services

Fixing a Noisy Water Heater: Why Calling a Plumber Is Your Best Move

A professional plumber can accurately diagnose the types of noises, resolve the root cause, and help prevent expensive repairs down the line.

  • Proper Diagnosis of Common Issues: Expert technicians can properly identify the source of unusual noises.
  • Safe Handling of Power and Gas Systems: A licensed plumber understands the risks involved and avoids issues during repairs.
  • Prevention of Safety Hazards: Noises can indicate serious problems like gas leaks or an imminent tank rupture. Plumbers are trained to handle these safety hazards and spot early signs of wear before they escalate.
  • Efficient Repairs That Save Money: DIY repairs can lead to active water leaks, void warranties, or cause damage to inner components. With expert help, you avoid unnecessary repair costs and keep your system running efficiently.
  • Upgrade Guidance When Replacement Is Needed: In cases where water heater replacement is the best option, a plumber can help you choose between different types of water heaters.
  • Peace of Mind with Professional Advice: A trusted plumber offers more than just a quick fix—they provide advice on water heater care, help you interpret water pressure signs, and recommend ongoing annual maintenance tasks to avoid future disruptions.

Don’t risk damage, downtime, or danger. Call a licensed plumber and restore peace and quiet to your home.

Speak with a Certified Plumber

Plomberie Pro-Drain: Expert Plumbing Services in Montreal

Whether it’s a water heater issue, clogged drain, pipe deterioration, or a full French drain excavation, Pro-Drain is equipped to handle it all—24/7. Our certified plumbers don’t just get the job done: they’re committed to providing durable, high-quality solutions to ensure a safe, efficient plumbing system that meets the highest standards.

Whether it’s residential repairs or complex commercial projects, we offer proven expertise, transparent communication, and a deep commitment to your peace of mind. Every service is guided by our commitment to providing reliable, thorough service focused on long-term value for our customers.

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