As a homeowner in the Greater Houston area, there are plenty of failure points that could affect your home at any time. The older your appliances get, the more likely they are to need some maintenance.

One common issue we get calls for is when a water heater is making a loud noise.

Do Water Heaters Make Noise Typically?

It is very common for water heaters to make noise. While some sounds are faint at first, they may grow progressively louder over the years. When a knocking, popping, or rumbling sound becomes noticeably louder, it may be time to call in a professional to see if a repair or replacement is required. Sometimes, simply cleaning your unit may be all that’s needed.

Why Is My Hot Water Heater Making Noise?

A water heater making noise can cause concern, but it’s not always a high-priority issue. There can be several causes behind a range of different noises coming from your hot water heater.

  • Knocking and Popping
  • Humming and Rumbling
  • Hissing and Screeching

We cover some of the most probable causes behind your loud water heater, and how to resolve them.

Knocking or Popping

Is your hot water heater making a knocking noise? There could be several culprits.

Popping and knocking in your water heater tank is frequently caused by residue buildup. Common sediment includes limescale (formed from water minerals), pebbles, sand, or other particles from water inflow. The sediment could also be a gel that results from using aluminum anode rods with a high ph water source. The noise occurs when hot water bubbles through this residue layer at the tank’s bottom.

hot water heater making knocking noise

If sediment surrounds the heating element in your heating tank, it can also lead to your water heater making a knocking sound. This will cause your heating element to work harder than before to heat the same volume of water. Before starting any repairs, make sure you understand what plumbing work you can do without a license in your locality.

To remove sediment from the tank, you will need to flush the tank and clean out the debris.

  1. Shut off the water supply and the gas/electric supply depending on which type of water heater you use.
  2. Attach a garden hose to the drain valve and drain the water from your water heater to a nearby drain. Be cautious because the draining water will be very hot.
  3. Close the drain valve.
  4. Fill the heating tank halfway from the cold water intake.
  5. Flush the water again.
  6. Repeat until no sediment is visible within the tank.

If the knocking/hammering sound is coming from your walls when you use hot water, it could be what is known as water hammering. Water hammering frequently happens when household utilities request hot water and the pipes in your walls expand/contract and cause a loud knocking sound. Your water heater isn’t in danger if this is the case but consider contacting a plumber if the noise gets progressively louder over time.

Humming or Rumbling

Like knocking, rumbling can also be from heated water passing through a layer of dirt or sediment. While this is not likely to cause immediate failure, it will make your heating element less effective and may require more energy to complete the same amount of work.

It’s also possible that a rumbling or humming sound is due to a loose heating element in an electric water heater. Determine how to tighten the heating element in your water heater model, then check to see if the sound persists.

Hissing or Screeching

If your water heater making a hissing noise? A hissing or screeching sound generally occurs when water is trying to flow through a small opening. This could mean that there are mineral buildups within your intake our outlet piping. This could also be from one of your valves not being fully opened.

If you suspect your piping has accumulated mineral deposits and buildup, contact a local plumber to help replace those elements.

Why Is My Tankless Water Heater Making a Loud Noise?

Tankless water heaters operate differently than traditional hot water heaters with holding tanks.

water heater making popping sound

When a fixture or utility in your house demands hot water, you may hear a clicking noise from the flow switch. This on and off clicking noise from your flow switch is normal and expected.

If the noise has grown increasingly loud over the years, it could be due to hard water calcium deposits. Installing a water softener (or regularly replacing the softener salt if you’re not already doing so) can help prevent this.

Less common causes of noises from a tankless water heater include burner issues, a leak in the combustion chamber, or a clogged fan. Noises from a tankless water heating unit aren’t as common as their tank counterparts, so contacting a plumber or the manufacturer is recommended if this happens.

How to Fix a Noisy Water Heater

Fortunately, if your water heater is making a loud noise, there is an easy fix – get quality plumbing repair in Houston from the professionals at URETEK Gulf Coast. According to the Texas Occupations Code, unless you’re the homeowner, you will need help from a licensed plumber in Houston to make most plumbing repairs.

Contact our team today to get an estimate on your plumbing repair work (Master RMP #40364). We’ve been serving homeowners in the Greater Houston area for nearly 20 years.