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Water Heater Making Popping or Rumbling Noises: What It Means and What to Do
The popping or rumbling sound coming from your water heater should not be ignored
A water heater is not typically the loudest appliance around the house. It spends most of its
time sitting quietly in the garage, basement, laundry room, or utility room completing its job
of providing hot water for the home. That means that water heater noises are often heard by
the homeowner long after the issue started.
A few pops when the water heater is running.
A low rumbling noise after a shower.
A crackling sound coming from inside the tank.
Then it gets louder and the homeowner has to wonder if their water heater is about to fail.
We hear this question quite often from our Placentia and North Orange County water heater customers and we are here to tell them that a noisy water heater does not always mean failure is imminent, but it does mean something should be done.
Water heaters making popping or rumbling noises are generally caused by sediment buildup
on the bottom of the tank, however, there are some caveats. Rheem notes that, "Rumbling,
popping, or crackling sounds coming from your water heater are often caused by sediment
buildup."
Why water heaters start to make popping noises
Standard water heaters function to store hot water. As water is added to the tank in order to
be heated it can leave behind minerals and sediment.
Over time this can create a barrier of debris on the bottom of the tank. When the burner or
heating element is turned on it heats up the water underneath the debris layer, causing it to
turn into steam and escape through the sediment in the form of noise. It is similar to the
sound of a pot on a stove with something stuck to the bottom. The heating process is still
happening but it is not an even transfer of the heat into the water due to the obstruction.
Rheem notes that this sediment buildup can cause decreased efficiency and extra stress on
the water heater's heating elements by acting as an insulator on the bottom of the tank.
Is a noisy water heater dangerous?
Not necessarily. However, it is not normal and should not be ignored.
While a little noise may not mean the tank is about to explode, it can mean it is working a
harder than it should be. The extra layer of sediment can decrease the efficiency of the tank
and cause it to work harder to achieve the desired temperature. If maintenance is not
performed the sediment layer can grow or become compacted and cause the tank to
operate at an unsafe level of pressure or temperature.
The EPA recommends that you flush your water heater once a year in order to reduce
sediment buildup that decreases efficiency.
This is why noise matters. It can be seen as a symptom of a greater issue.
Other signs that sediment may be causing
problems with your water heater
Noise is usually the first sign that sediment buildup has occurred, however, there are some
other signs that a homeowner can look for.
They include:
Hot water is running out sooner than usual.
The water heater seems to take longer to begin producing hot water after showers.
The tank is operating more frequently than normal.
Visible signs or water that has been discolored or contains rust.
The tank has not been serviced in years, or at all.
There is visible water near the base of the tank.
The tank is old and/or has had a lack of maintenance.
The tank is making additional noises, such as a banging sound, that might be coming from the pipe system in the house or the tank itself.
If several of these signs are noticed by the homeowner it is probably wise to call for
professional service.
Can flushing help a popping water heater?
Sometimes. If the noise is caused by sediment buildup and the rest of the water heater is in
good condition it is likely that flushing the tank will reduce the noise level and restore some
of the efficiency of the tank.
However, there is a caveat.
If the tank is old, corroded, leaking, or hasn't been serviced in years the owner should not try
to open the drain valve and remove the sediment with a professional plumber unless they
have called one to the house to inspect the unit first. Older drain valves have a higher
propensity to leak after being tampered with and sediment that has been sitting in the tank
for years can reduce the effectiveness of flushing due to the compaction.
Yes, it can. But the condition of the tank can matter.
When the sound may point to a bigger issue
Popping and rumbling are usually caused by sediment buildup in the tank, but that does not
mean that all unusual noises are the same.
A professional plumber should be called in for service if any of the following are true:
The noise is getting louder.
The tank is leaking.
The hot water performance has suddenly changed.
There is visible rust or corrosion.
The pressure relief valve is releasing water.
The tank is old and/or lacking in maintenance.
There is an odor of gas near the tank.
The tank is making a bangng sound in the plumbing system.
A water heater tank that is leaking from the pressure vessel itself is a replacement
conversation as is a tank with visible corrosion around the base.
Why Southern California homeowners notice
this problem
Southern California water has a reputation for being filled with minerals based on what
region the water is coming from, so a homeowner may have already noticed signs of the
issue without realizing it. White deposits on the rim of the sink, spots on the glass shower
doors, a malfunctioning or low-pressure shower, or a clogged aerator on the kitchen or
bathroom sink can all be signs of mineral buildup in the water. This same kind of activity can
be occurring inside of a tank water heater and causing similar issues.
The more hot water that is used in the house, the more the water heater works. Multiple
people taking showers, laundry being washed, dishes being cleaned, and other uses can all
add up. The more the tank is working, the more opportunity there is for it to show that it
needs help in a non-emergency way, such as noise.
What not to do when your water heater starts making noise
Do not wait months to address it
If the tank is making new noises schedule a service appointment before it gets worse.
Do not assume that it is just sediment-related
Flushing the tank may help if the issue is sediment-related, but it will not address failing tank
components, a faulty heating element, issues with the venting, gas control, or a leak.
Do not force an old drain valve
If the drain valve is old, brittle, stuck, corroded, or leaking forcing it can cause issues.
Do not continue to increase the temperature setting
If the hot water is running out faster increasing the temperature may not address the cause
of the issue and can lead to scalding.
Do not ignore water near the base of the tank
Noise plus water near the base of the tank should prompt an immediate call to a local
plumber.
What Kramer’s Plumbing looks at when a
homeowner calls about a noisy water heater
When Kramer’s Plumbing shows up for a service call about a noisy water heater in Placentia
or the North Orange County area we take a moment to evaluate the situation. We do not just
inspect the tank, we look at the entire unit. We consider the age, the condition of the tank,
the state of the drain valve, any signs of corrosion, water near the base of the tank, the
condition of the hot and cold water connections, the venting for gas units, the condition of
the temperature and pressure relief valve area, whether the tank should be flushed, and
whether repair or replacement is the better option.
Sometimes it is maintenance, sometimes it is repair, and sometimes it is replacement.
Repair, flush, or replace?
The right option depends on the age and condition of the water heater in question. Flushing
the tank can make sense if the unit is newer, not leaking, and the noise seems to be
sediment-related. Repair can make sense if the issues are related to a component, valve,
connection, or setup. Replacement can make sense if the tank is old, leaking, corroding,
and/or unreliable.
A noisy water heater is not always a replacement scenario, but when the tank itself is
nearing the end of its lifespan it may not be wise to continue to spend money servicing it.
FAQ: Water heater popping or rumbling noises
Why is my water heater making popping noises?
Popping noises are often caused by sediment buildup in the tank. The sediment layer can
cause water to get trapped underneath and it can make noise as it heats up and escapes.
Is a rumbling water heater dangerous?
Not necessarily, but it should be inspected. A rumbling water heater can be a sign of
sediment buildup, extra stress on the system, or a lack of proper maintenance.
Will flushing stop the noise?
It can if the issue is sediment-related and the water heater is not in an otherwise failing state.
Should I flush an old water heater?
It should be inspected by a plumber first if the tank is old, corroded, leaking, or has a stuck
drain valve.
Why does my hot water run out faster now?
Sediment buildup can reduce the amount of usable hot water or reduce the efficiency of the
tank.
When should I replace a noisy water heater?
When the tank is old, leaking, corroding, unreliable, or it is continuing to make noise after
maintenance has been completed.
Can tankless water heaters make noise too?
Yes, however, the causes are different. Depending on the noise tankless water heaters can
require descaling, maintenance, or additional service work.
When should I call Kramer’s Plumbing?
When the noise is new, loud, getting louder, is paired with leaking, or is happening on an
older water heater which has not been serviced in years.
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