A water heater that starts making unusual sounds is trying to tell you something. In Springfield MO, the most common water heater noises — popping, rumbling, hissing, banging — each have a specific cause with a specific fix. Here is what every noise means and what to do about it.
Popping or Rumbling Noise (Most Common)
Cause: Sediment Buildup at the Bottom of the Tank
Hard water minerals settle at the bottom of the tank. When the heating element activates, water trapped under the sediment layer boils and pops through it.
Fix: Flush the Water Heater
Flushing the tank removes the sediment. Do this annually. If popping continues after flushing, the sediment may be calcified — a sign the tank needs replacement.
Hissing or Sizzling Sounds
Cause: Water contacting a hot surface — either condensation dripping on a burner (normal on new tanks) or, more seriously, a slow leak dripping onto the burner assembly.
What to do: If hissing is accompanied by any moisture near the unit, call a plumber immediately. A leaking water heater tank cannot be repaired — it must be replaced.
Banging or Knocking (Thermal Expansion)
Cause: Water hammer — pressure surges when hot water valves close quickly cause pipes to knock against framing. Also caused by thermal expansion of pipes as they heat and cool.
Fix: A licensed plumber can install a thermal expansion tank or water hammer arrestors on supply lines. Do not ignore persistent banging — it stresses pipe joints.
Ticking Sounds from the Tank
Cause: Normal thermal expansion and contraction as the tank heats and cools. Usually heard during heating cycles. Not a sign of damage.
What to do: If ticking is mild and intermittent, it is normal. If it intensifies or combines with other noises, have a plumber inspect the unit.
Screeching or Whining Noises
Cause: Water being forced through a partially closed valve — usually a supply valve not reopened fully after maintenance, or a failing inlet valve.
Fix: Check that all supply and outlet valves are fully open. If the sound persists, the valve is failing. Call a plumber.
How to Flush Your Water Heater in Springfield MO
Step 1: Set thermostat to Pilot (gas) or turn off breaker (electric).
Step 2: Connect a garden hose to the drain valve at the tank bottom. Run to a drain or outside.
Step 3: Open a nearby hot water faucet to prevent a vacuum.
Step 4: Open the drain valve and let the tank empty. Flush with cold supply briefly once clear.
Step 5: Close the valve, refill the tank completely, then restore power or relight the pilot.
When Noise Means You Need a Plumber
Call (417) 373-4862 if you have:
•Popping that continues after flushing (calcified sediment — replace unit)
•Any hissing with visible moisture or leaking
•Banging that has not responded to a hammer arrestor
•A unit that is 10+ years old with any of the above
•Screeching that persists after checking all valves
Frequently Asked Questions — Water Heater Noises Springfield MO
Q: Why is my water heater making a popping noise?
A: Sediment buildup at the bottom of the tank. Flush it annually. If it continues after flushing, the tank may need replacement.
Q: Is a noisy water heater dangerous?
A: Most noises are not immediately dangerous but indicate wear. Hissing with moisture is an exception — call immediately.
Q: How often should a water heater be flushed in Springfield MO?
A: Once per year. Homes with hard well water: every 6 months.
