Quick Answer: Why Your Water Heater Is Making Noise

If you hear a banging or knocking sound in your utility room, there is a good chance it is your water heater making noise. The cause could be water hammer in your home’s plumbing, sediment inside the tank, thermal expansion, a loose heating element, or even high water pressure. Some issues are simple DIY fixes, while others call for a licensed plumber. If you are in Lake County, IL or Kenosha County, WI, Watertight Plumbing is ready to help 24/7 with fast, reliable service so you can restore quiet and protect your home.

Is It Safe? When To Shut It Down Immediately

Most noises are not an emergency, but some signs mean you should act fast to protect your family and your home.

  • Smell of gas or rotten eggs near a gas water heater. Turn off the gas supply, avoid sparks, and call your gas utility and a professional right away.
  • Carbon monoxide alarm sounding. Leave the building and call emergency services and a licensed pro.
  • Active leak, spraying water, or a bulging tank. Turn off water supply to the heater and shut off power or gas. Then call a plumber.
  • Scorch marks, melting plastic, or burning smells. Cut power at the breaker or turn off the gas. Do not relight or reset.
  • Temperature and pressure relief valve discharging constantly. This can signal dangerous pressure. Shut it down and call for service.
  • Water pressure over 80 psi or no working expansion tank on a closed plumbing system. High pressure can damage appliances and cause loud banging.

Common Water Heater Noises and What They Mean

Banging or Knocking

A sharp bang or knock that happens when a faucet or appliance shuts off is often water hammer. Water flow stops suddenly and the shock wave slams into pipes or the water heater. If the sound happens primarily from the heater itself during heating cycles, it may be sediment popping, thermal expansion clicking, or the tank flexing. If you hear banging along basement joists or wall cavities, loose pipes are likely vibrating against wood or metal.

  • Water hammer from fast-acting valves like washing machines or ice makers
  • Loose plumbing straps or pipes touching framing
  • Thermal expansion in a closed system without a working expansion tank
  • Sediment heating and exploding tiny steam bubbles inside the tank

Rumbling or Popping

Rumbling and popping are classic signs of sediment buildup. Minerals settle at the bottom of the tank and trap hot water. As the burner or element heats, steam bubbles form and burst through the sediment layer, causing a popping sound. This reduces efficiency and can shorten the heater’s life.

Sizzling or Hissing

Sizzling usually means water is dripping onto a hot burner, or a small leak is hitting a hot surface. It can also be normal condensation sizzle when a cold tank first starts heating on a humid day. Persistent sizzling, especially with visible moisture, needs attention.

Whistling or High-Pitched Screech

A whistling sound can come from partially closed valves, a clogged inlet screen, a failing pressure relief valve, or high water pressure forcing water through a small opening. It may also happen if the temperature and pressure relief valve is beginning to fail or if an isolation valve is not fully open.

Humming or Vibrating

Electric models can hum if the heating element is slightly loose and vibrates during operation. Gas models can hum if the burner or draft fan vibrates, or if the flue baffle is resonating. Slight hums can be normal, but loud vibrations point to a part that needs adjustment or replacement.

Ticking or Tapping

Tapping sounds often come from thermal expansion and contraction. As metal parts heat and cool, they expand and contract, causing light ticks. This is usually harmless. If the ticks are loud and accompanied by movement in the piping, secure the pipes and add cushioning at contact points.

Gurgling or Trickling

Gurgling near the drain line or relief valve discharge pipe could indicate the temperature and pressure relief valve is passing water. This can be normal after a heating cycle in a closed system, but frequent discharge means pressure issues that need a pro.

How To Diagnose Where the Noise Comes From

  1. Stand near the water heater during a full heating cycle. Note whether the noise occurs when the burner or elements are active or when water is shut off at fixtures.
  2. Have a helper open and close a nearby faucet rapidly. If the bang hits at closure, you likely have water hammer.
  3. Touch the hot and cold lines leading to the heater carefully. Feel for vibration as the sound occurs. Do not touch vent pipes or hot surfaces.
  4. Check the expansion tank above the heater. Tap it lightly. It should sound hollow at the top and more solid at the bottom. If it is waterlogged or heavy, it may have failed.
  5. Inspect pipe straps and support points. Look for pipes touching framing or ductwork. Add cushioning where needed.
  6. Open and close isolation valves on the heater fully. A half-closed valve can whistle or squeal.
  7. Look at the temperature and pressure relief valve discharge pipe. Any signs of recent water? That hints at pressure issues.
  8. See if sediment is present. Drain a quart from the drain valve into a clear container. If it is cloudy with grit, you likely have buildup.

DIY Fixes You Can Try Today

Flush Sediment From a Tank Water Heater

Flushing removes minerals that cause rumbling and popping and helps your heater run more quietly and efficiently. If you are not comfortable, call Watertight Plumbing for a professional flush.

  1. Turn off power at the breaker for electric units. For gas units, set the thermostat to pilot or vacation and close the gas valve if you will fully drain.
  2. Shut off the cold water supply to the heater.
  3. Attach a garden hose to the drain valve at the bottom of the tank and run it to a floor drain or outside.
  4. Open a hot water faucet at a nearby sink to let in air.
  5. Open the drain valve slowly and let several gallons run out. If you plan a full flush, drain the tank completely.
  6. Briefly open the cold water supply to stir up sediment, then drain again. Repeat until the water runs clear.
  7. Close the drain valve. Disconnect the hose.
  8. Turn the cold water supply back on to fill the tank. Keep a hot faucet open until a steady stream of water flows without sputtering.
  9. Restore power for electric units only after the tank is full. For gas, relight according to the manufacturer label if you turned it off.

Tip: If the drain valve clogs with sediment, very carefully use a short piece of wire to clear it. Protect your eyes and hands. If it will not clear, stop and call a pro.

Reduce Water Hammer

  • Install water hammer arrestors on quick-closing valves like washing machines or dishwashers. These small devices absorb shock waves.
  • Secure and cushion pipes with proper clamps and foam where they contact framing.
  • Replace old globe valves with quarter-turn ball valves that open and close smoothly.
  • Slow the closing speed of appliance solenoid valves if adjustable.
  • Check your pressure reducing valve if you have city water. Aim for 50 to 70 psi.

Quiet Expansion and Temperature Issues

  • Set water heater temperature to about 120 degrees F to reduce expansion stress and save energy.
  • Install or service a thermal expansion tank on closed systems with a check valve or PRV. Set the tank’s air charge to match your home’s water pressure.
  • Add an anti-scald mixing valve to provide safe tap temperatures while the tank stays efficient.

Silence a Humming Electric Element

  • Turn off power at the breaker. Remove access panels and verify power is off.
  • Tighten the element with a proper wrench. If the element is scaled or damaged, replace it with the correct wattage and length for your model.
  • Refill and bleed air before restoring power.

Fix Sizzling From Leaks or Condensation

  • Check all connections and valves for drips. Tighten gently or replace worn washers and gaskets.
  • In humid weather, some condensation is normal. Make sure the area is ventilated and the flue is drafting properly for gas units.
  • If you find a persistent leak at the tank seam or the temperature and pressure relief valve, call a licensed plumber.

For Tankless Units: Scale and Flow Issues

  • Descale the heat exchanger annually in hard water areas. Follow the manufacturer’s flush procedure with a pump and food-grade descaler.
  • Clean the cold water inlet screen filter. A clogged screen can cause whistling and chattering.
  • Verify correct gas supply and venting. Poor combustion can cause noise and error codes.

When To Call a Professional

Some problems behind a water heater making noise point to safety or warranty issues best handled by a pro.

  • You smell gas, see scorch marks, or your carbon monoxide alarm sounds.
  • The temperature and pressure relief valve discharges often.
  • Water pressure is above 80 psi or you lack a working expansion tank.
  • Flushing does not reduce rumbling and popping, or the drain valve is clogged.
  • You have a persistent leak from the tank body or fittings.
  • Electrical issues, tripped breakers, or melted wiring are present.
  • You prefer a maintenance plan or want to upgrade to a high-efficiency or tankless system.

Watertight Plumbing provides 24/7 emergency and scheduled service. Their licensed, bonded, and insured team will diagnose the cause, explain options clearly, and complete the repair or replacement to code.

How Watertight Plumbing Can Help

Watertight Plumbing, also known as Water Tight Plumbing and Sewer, is a family-owned company with more than 30 years of experience serving Lake County, IL and Kenosha County, WI. From Zion and Waukegan to Gurnee, Libertyville, and Kenosha, their team delivers quick, reliable service for homes and businesses. If your water heater is making noise, they can inspect, flush, repair, or replace your system the right way.

  • Emergency plumbing response for water heater failures, burst pipes, gas leaks, and sewer backups
  • Water heater services for gas, electric, and tankless models, including installation, maintenance, and troubleshooting
  • Sewer inspections, rodding, line repairs, and drain cleaning to stop gurgling and backups
  • Sump pump installations, repairs, and battery backups to protect basements
  • New construction and remodeling plumbing upgrades with permits and code compliance
  • General plumbing repairs for water lines, fixtures, toilets, and more

Call Watertight Plumbing at (847) 623-6810 for Lake County or (262) 484-4520 for Kenosha County. They are ready around the clock.

Preventive Maintenance To Keep Your Water Heater Quiet

  1. Annual tank flush. Remove sediment before it hardens and reduces efficiency.
  2. Check the anode rod every 2 to 3 years. Replace it when it is 50 percent worn to prevent corrosion and extend tank life.
  3. Inspect the expansion tank yearly. Set air pressure to match household water pressure and replace the tank if the internal bladder fails.
  4. Test the temperature and pressure relief valve. Lift the lever briefly once a year to ensure it moves freely. Replace if it drips or will not seat.
  5. Verify water pressure. Keep it between 50 and 70 psi with a pressure reducing valve if needed.
  6. Install a sediment filter or water softener in hard water areas. This reduces scale that causes rumbling and shortens element life.
  7. Secure and cushion pipes. Prevent banging by keeping pipes from rubbing on framing.
  8. Schedule a pro inspection. A licensed plumber can spot safety issues, adjust the gas valve and venting, and confirm electrical elements are sound.

FAQs About a Water Heater Making Noise

Why did the banging start after new plumbing or an appliance upgrade?

New valves and appliances like high-efficiency washers close very fast, which can create water hammer. Your old system may not have had arrestors or a working pressure reducing valve. Adding arrestors and checking pressure usually solves it.

Is it normal for a new water heater to make sounds?

Light ticks and soft whooshing are normal as metal heats and cools. Loud banging, whistling, or ongoing popping are not normal. If a new heater is noisy, have the installer check sediment in the lines, venting, and gas or electrical connections.

How long can I ignore a rumbling tank?

Rumbling means sediment is present. You might still get hot water for a while, but efficiency drops and stress on the tank increases. A timely flush can save energy and extend the life of the heater. Waiting often leads to harder, stubborn scale.

Will replacing the water heater fix the noise?

Sometimes, but not always. If the cause is water hammer or high pressure, a new heater will still make noise until the system issue is fixed. A professional diagnosis makes sure you solve the root cause.

How much does it cost to fix a noisy water heater?

Costs vary with the cause. A simple flush is usually affordable. Adding hammer arrestors or an expansion tank costs more but protects the whole system. Major repairs or replacements depend on the model and fuel type. Watertight Plumbing provides clear, upfront pricing after a quick on-site evaluation.

Can I flush my tankless water heater myself?

Yes, many homeowners do a yearly descaling with a small pump and descaler. Follow your manual closely and shut off power and gas. If you prefer, Watertight Plumbing can handle it and check venting, combustion, and filters at the same time.

Ready To Restore Quiet? Contact Watertight Plumbing

If your water heater is making noise, do not wait for a small annoyance to become a costly repair. The friendly experts at Watertight Plumbing will find the source fast, explain your options in plain language, and complete the fix with quality parts. From quieting water hammer to flushing sediment or installing a new high-efficiency or tankless system, they do it all with care. Call (847) 623-6810 in Lake County or (262) 484-4520 in Kenosha County. Serving Kenosha, Zion, Waukegan, Gurnee, Libertyville, and surrounding communities, Watertight Plumbing is your local partner for safe, quiet, and reliable hot water.