6 Early Signs of Water Heater Failure
Knowing these early signs of water heater failure may prevent a water heater failure emergency before it happens (saving yourself money and stress in the long run).
If you run a restaurant, hotel, or apartment building, just thinking about a “no hot water” situation might make you panic. No dishwashers or hot showers? No thank you! After all, you need hot water to run your business. Remember: your commercial water heater is a mechanical piece of equipment. So it’s not a matter of if your water heater will fail—it’s a matter of when. Eventually, all hot water heaters fail. But you can be prepared. Look for these early signs of water heater failure—and learn what to do when your commercial water heater is acting up.
Skip to the water heater problem you’re experiencing:
Good news! You can stay ahead of the game by recognizing the visual signs (signs you can see) and the auditory signs (signs you can hear) that your water heater is about to fail. These signs indicate your water heater might be on its last legs—so if you’re experiencing these symptoms, it’s time to get your commercial water heater checked out by a trained water heater technician.
Signs of Water Heater Failure You Can See
As time marches on, your water heater will eventually fail. Unfortunately, nothing lasts forever, especially equipment that works as hard as a commercial water heater. What keeps a water heater failure from turning into a hot water disaster is knowing the signs to watch for before the inevitable failure.
As part of your team’s regular maintenance routine, we recommend a quick monthly visual inspection of your equipment. It takes just seconds, but you’ll notice these early signs of water heater failure long before they’ve become a serious concern that leaves you without your much-needed source of hot water.
So what are the signs? Let’s start with the visual signs of water heater failure—the signs you can see, since they’re often the first indication that there could be a problem with your hot water heater.
Visual Sign of Water Heater Failure # 1: Dripping or Leaking Water Heater
When you see some water on the floor near your water heater, it’s essential to figure out where the leak comes from—failure to understand what to do when your water heater leaks could result in a dangerous situation.
Here’s what you need to know about water heater leaks!
Possibility # 1: Condensate
If you notice a little condensation (moisture) on your water heater, this is typically normal and not a sign your water heater is failing. However, condensation looks different on standard (atmospheric) water heaters than on high-efficiency water heaters.
How do you know which type of water heater you have? A quick rule of thumb is to check the top. If a large metal pipe is coming out of the center, it’s likely a standard atmospheric water heater. If there aren’t any top pipes, or the vent pipes are PVC instead of metal, it’s most likely a high-efficiency water heater.
Most high-efficiency water heaters are “sealed combustion” units that gain efficiency by extending the path the combustion gasses travel within the water heater, slowing them down to make use of as much available heat as possible. This process generates condensate discharged through a condensate drain near the bottom of the tank. So, condensation is a healthy sign that your high-efficiency water heater is working correctly!
Standard atmospheric water heaters typically don’t produce condensate. However, drastic differences in temperature between the water tank and the air outside the unit can sometimes result in a small amount of condensation on the outer jacket, which will happen within minutes of installing any atmospheric water heater. After that, condensation will typically only occur if you use all the hot water quickly and the tank refills with water colder than the surrounding air—similar to a cold beverage on a warm day.
The Solution:
Condensation is normal and typically not a problem or an early sign of water heater failure. Be sure your basement or room where you keep your hot water heater has proper drainage.
Possibility # 2: T&P Valve
When you see water on the floor near your water heater or dripping from the pipe that runs down the side of the unit, your temperature and pressure (T&P) valve is venting excess steam. This steam condenses into water, which travels down that pipe and into your floor drain, preventing your water heater from exploding. A slow drip from the T&P or “pressure release” valve is normal.
NEVER tamper with or block the T&P valve or pipe. Proper operation of the T&P valve is critical to safe water heater operation. (Have you seen the Allstate water heater Mayhem commercial? It’s no joke!)
The Solution:
If you’re concerned that a large volume of water is coming from the T&P pipe (or elsewhere on your commercial hot water heater), it’s time to call a trained water heater technician. A constant flowing stream can indicate that the T&P valve is faulty or broken—even small leaks are a concern. If the seal has broken, it will leak water, compromising the integrity of this vital safety feature. Again, always call a trained water heater technician if you suspect a problem with your T&P valve. DO NOT tamper with the T&P valve. A T&P valve that is capped, blocked, missing, or broken cannot release built-up pressure, which could cause your water heater to explode.
Seriously. Watch the MythBusters tamper with a water heater, turning it into a rocket:
Possibility # 3: A Leaker
In the commercial water heater industry, there’s a reason we call a failed hot water heater a “leaker.” When a standard atmospheric water heater is leaking water from the bottom of the tank, it’s a sure sign you’ve got a leaker—meaning your water heater is about to fail completely and SOON.
When water comes from the base of the water tank (or if you notice water on the floor under the water heater), your commercial water heater is leaking internally. Your water heater is losing the water it’s supposed to be heating. Small leaks can happen slowly over time or very abruptly. These leaks occur because the metal expands and contracts when the water heater tank heats up and cools down. Over time, hairline cracks form in the tank itself or in the flue tubes inside the water heater, causing water to leak out onto the floor.
Typically, only standard atmospheric water heaters become obvious leakers. Many high-efficiency (sealed combustion) water heaters can become leakers without any advanced visual signs. High-efficiency (sealed combustion) water heaters leak too, but these units have combustion chambers at the bottom, so when an internal tank leak develops, it spreads into that chamber under the tank and isn’t visible from the outside. Instead, the leak will typically extinguish the burner, preventing the heater from firing.
The Solution:
Unfortunately, the only solution to any leaker is a water heater replacement. If your high-efficiency water heater displays an error code or is “locked out,” refer to your manual for the diagnosis code to prepare your water heater technician for your service call. Call a qualified business to service and replace commercial water heaters. (In the Midwest? Contact Reliable Water Services.)
Visual Sign of Water Heater Failure # 2: Corrosion
If you notice a lot of corrosion around the pipe fittings attached to your commercial water heater, this indicates that water is leaking through what should be sealed pipe fittings. Pipe fitting corrosion occurs because mineral deposits from the water seep through the gaps in those pipe connections. This situation is often called a “slow leak,” which means your water heater might be able to limp along for a while, but it will fail if you don’t address the problem.
The Solution:
A slow leak through the pipe fittings or along the bottom of the tank welds causes corrosion; corrosion is a sure sign of imminent water heater failure. You’re lucky your water heater has a little time left, but don’t delay. You’ll need a water heater replacement SOON—it’s just a matter of time. Even if the leak “seals itself shut” with sediment, that sediment will soon crack, and then you’re looking at a full-on leaker. A leaking water heater can be a big problem (and mess). Contact a professional commercial water heater technician as soon as possible.
Visual Sign of Water Heater Failure # 3: Burn Marks
If you see burn marks on the bottom of your water heater, that’s typically an indication of two possible problems. (Note: Burn marks are only an issue for standard atmospheric water heaters.)
Possibility #1: Improper Venting
Burn marks on your commercial hot water heater could mean improper water heater venting is causing backdrafting. Backdrafting is a severe problem that requires urgent attention and repair because you’ve got natural gas and exhaust fumes that aren’t exiting your building as they should. It doesn’t necessarily indicate a water heater problem but a structural venting issue. Those toxic fumes are seeping into your establishment—NOT a good situation.
The Solution:
If your issue is improper venting, there’s likely no need for water heater replacement—you’ll need to call a plumber to fix the venting. However, if you don’t fix the venting, your water heater WILL fail prematurely (as will any subsequent water heater replacements). So don’t wait! Find more information on water heater venting here.
Possibility #2: Damaged Flue Pipes
Burn marks can also indicate that the flue pipes (located inside the water heater) are blocked or damaged. A flue problem is also potentially unsafe, so the water heater will need to be replaced soon. What’s causing the damage to the flue pipes? Are the pipes blocked? You will need a professional to diagnose the issue. There could be something like a bird’s nest in the top of the flue or chimney stack. There could also be something going on inside the water heater itself.
The Solution:
Call a plumber ASAP. You need to have the water heater shut down until the problem is resolved to prevent any dangers while the water heater is broken. You will likely need a water heater replacement, and for safety’s sake, this isn’t a problem to ignore or postpone. Address damaged flue pipes right away.
Visual Sign of a Water Heater Failure # 4: Yellow Flame Color
While your water heater is running, you’ll notice a nice, blue-colored flame underneath the tank, heating your water. If that pilot light flame is yellow or orange instead of blue, this is an indication that the burner isn’t working correctly, and the water heater unit needs to be serviced. Like the flame on your gas stove, a yellow-hued flame means it’s burning too cool. (Note: This is an issue for standard atmospheric water heaters only.)
The Solution:
In this case, cleaning or replacing your water heater’s burner is likely the only repair you’ll need. However, suppose you see a yellow flame in conjunction with burn marks on your water heater (as noted in Visual Sign # 3 above). In that case, that’s usually an indication of insufficient make-up air available. It signifies that the flame is starving for the air it needs to burn hot.
Signs of Water Heater Failure You Can Hear
If you’ve been doing monthly visual inspections on your commercial water heater, you’ll likely notice the visible signs of water heater failure first before you start hearing sounds. That said, sometimes, the signs of water heater failure occur inside the unit, making it hard to notice with your eyes alone.
That’s when listening to your water heater comes into play. Now, it may sound like an odd activity—listing to your water heater, but the truth is that the noises are often pretty clear and noticeable. Taking just a few moments each month to listen to your equipment will help you identify an issue before you run into a water heater emergency.
What does water heater failure sound like? Here are two auditory signs that your water heater might require professional assistance.
Auditory Sign of Water Heater Failure # 1: Popcorn Sounds
The most apparent auditory signal that your standard atmospheric water heater is about to fail is when it sounds like a popcorn machine. A popping noise from your hot water heater comes from an accumulation of honeycombed mineral sludge caused when that water heater takes on hard water. Water trapped in that honeycomb becomes super-heated because the sediment layer forms directly above the heating element and flashes off into steam. That flash-boiled water is causing those pop POP popping noises.
The Solution:
Eventually, that sludge will stress your water heater tank, causing a leaker, and you’ll need a replacement commercial water heater. Those loud popcorn sounds also indicate that it’s time to invest in a water softener! Without a water softener to filter out that mineral sludge and gunk, your water heater tank becomes extremely inefficient and more prone to a shortened life and impending failure. A water softener won’t solve the existing sediment problem in your current water heater, but it will minimize (and hopefully eliminate) any future sediment build up in your new replacement water heater.
Auditory Sign of Water Heater Failure # 2: Loud Blower Motor
If your water heater setup has a blower motor attachment on the water heater itself, and the blower motor is unnaturally noisy and just plain LOUD, that means the blower bearings are about to fail. Here’s the thing: when that blower motor dies, your water heater won’t work. Why? Because your water heater is equipped with a failsafe mechanism that prevents operation in case of blower failure.
All high-efficiency (sealed combustion) water heaters have blower motors. If you have a standard (atmospheric) water heater, you most likely don’t have a blower motor unless you may have a hybrid power-vented setup (not typical).
The Solution:
Unfortunately, sometimes blowers are just loud. It could be your water heater is simply working hard. Listen for a distinct sound of rattling/tinkling/clinking metal. If that’s what you’re hearing, you may need your water heater’s blower motor replaced.
Look & Listen for Warning Signs to Prevent Dangerous Water Heater Failure
So, the moral of the story is stop, look, and listen for the signs of water heater failure. When you know and understand the visual and auditory signs of looming commercial water heater failure, you can prevent an emergency situation before it happens. In addition, the more you know about your commercial water heater, the more likely you’ll be able to stay in hot water, and the better off your restaurant, hotel, apartment, or other commercial enterprise will be in the long run.
If you feel you might be experiencing one of the signs of water heater failure, don’t wait. Reach out today; our technicians can help you get to the bottom of your water heater problems!
Featured image courtesy of Wikimedia Commons – licensed under CC Public Domain.
It might not be at the top of your list of priorities to learn how to remove an outdated water heater. Yet eventually you will outgrow your water heater or it will reach the end of its useful life. You’ll be relieved to know how to take the old unit out and put in the new one.
It was really helpful when you said that popping noises are a bad sign. My sister was at my house yesterday afternoon for lunch, and she talked about how she has been hearing weird popping noises coming from her water heater for the past couple of days. I’ll pass this information along to her so she can look into hiring a professional to come and fix the issue for her.
We all use water heaters in our daily routines for things like showering and washing up. And because we use them so often it is important that we make sure we invest in water heater maintenance on a regular basis in our homes. It is common for water heaters to wear out or breakdown and monitoring this is an important task.
Thanks so much for talking about the different issues to look out for in water heaters that are failing. My water heater has begun to make odd noises and stop running randomly and I’m not sure why. I’ll have t look into calling down a professional to see if it can be repaired or if it needs to be replaced.
Got a water heater element bad and when I removed the cover to replace it there was water in the insulation below it does this mean anything because it’s on the outside of the holding tank around the shell ,but my pan and floor are dry. Pls help. Never run into this before it’s a whirlpool ?
Hey so my water heater went out I turned it on no problem and waited for a little for hot water it was warming up slowly so I want to check make sure its was still on and noticed that the lil window was glowing red. Is that normal? Does it looks like that when its heating up water it first or is something wrong with it. I turned it off and am looking to see what that means if normal or? But cant find anything so far if you could let me no that’s would be great ty
Hi Michael,
It’s difficult to say if this is normal without knowing what type of water heater you have and what you mean by little window. If you have a gas fired water heater, it’s possible that what you’re seeing is just the burner fired up. However, that should be producing more of a blue flame glow, not orange. An orange flame is usually an indication that your heater is starving for fresh air which can lead to problems. Our post about make-up air has more info on this and things you can do to solve it: https://reliablewater247.com/importance-of-make-up-air/. But when in doubt, we always suggest calling a professional service provider if you have concerns, especially if your heater had already gone out prior to this. It could be that your burner just needs to be cleaned of rust, dust or other debris, as these things tend to build up over the years causing blockage that can prevent your heater from firing up properly, or at all. Hope this helps!
what a post. thanks!
The three common signs that point towards the fact that you need to replace your water heater are:
Low water heat pressure
Distasteful or rust coloured water
Inconsistent water heat.
When you notice these signs you must immediately call in a professional plumber to get you water heater checked and if needed replaced.
It’s helpful that you mentioned that burn marks are obvious signs that heater repairs are needed soon. I’d like to make sure that my heater is in good condition this winter because I easily get the sniffles when it’s cold. I probably should get repairs and maintenance a little bit earlier next year.
Recognizing the signs that water heater failure is threatening will allow you to replace this vital appliance before you wake up to a cold shower.
Thanks for making a list of the signs of water heater damage. Apparently, I’ve been having some issues with my system because of the strange noise it produces upon usage. I never thought that this simply means that the blower bearings in the unit are about to fail, which leads to a malfunctioning water heater. With that said, I’ll look for a local plumber who can fix it for me.
I have an A.O. Smith water heater. One of the features according to technical support is if it gets wet even on the bottom couple of inches you must replace the water heater it will not operate. Any thoughts on how I might overcome that issue?
Hi Bill,
Sorry for the delayed response. Assuming you’re dealing with an unfortunate flooding situation, sadly it’s true – most manufacturers suggest replacing any water heater that has been submerged in water, primarily for safety. The burner assembly & many of the electrical controls are typically located on the bottom of water heaters, and when those elements are submerged their functionality becomes compromised. Water is already corrosive to metals and other materials, but flood waters can contain additional corrosive elements & chemicals picked up from the environment, depositing unknown debris on equipment before receding. Even if everything is allowed to dry out with time and the water heater can fire up again, it’s still risky to run it. There can be unseen damage to parts that could pose safety hazards later, such as a wiring shortage or a gas valve corroding away & leaking. Additionally, the insulation between the jacket & metal holding tank is also likely to have gotten wet, soaking up extra water that may never fully dry due to lack of air flow. This can cause the metal tank to corrode more quickly, from the outside, and can also lead to mold problems. We typically recommend including the cost in your insurance claim. For further reference, here’s the AO Smith specific bulletin: https://www.hotwater.com/lit/bulletin/bulletin0823.pdf If your basement is prone to frequent flooding, you could try preventing the chance of future water damage by installing the next water heater on an elevated platform to keep it away from the danger zone, or by going with a tankless unit. Did this answer your question?
Thanks for sharing this as it is very helpful since it could really save a lot of people’s lives. Great blog!
Thanks for mentioning that corrosion can indicate that your water heater is having problems. I’ve noticed that my water heater has some corrosion. I’ll definitely have a professional come to take a look and see if I need repair or replacement.
Just had a new propane water heater installed about 3 weeks ago and it is direct vent to the outside wall,
When it starts up and is running we are experiencing a motor noise upstairs in our living space.
The water heater is in the basement… We have had the installers back about 4 times and each time they give us a different cause…One said there is condensation in the elbow of the vent outside, another one says there is no condensation and the list goes on..The noise is very annoying and our old heater was perfectly quiet. It had a small leak and because it was a rental tank, our propane company installed a new one…wish we would of had it repaired…do you have any idea what is causing the motor noise or do we just put up with it
Hi Donna, How would you describe the noise the new unit is making? Was your old water heater also a direct vent setup? And is it a powered direct vent heater, or just direct vent? It is difficult to say what could be causing the noise without knowing more specific details. However, if the unit is actually a powered direct vent unit, then it would have a powered fan assembly to help the exhaust gasses vent outside, and those blower motors can get a bit noisy when they are actively running. The noise could simply be that the new model is slightly different and a little noisier than the old one – especially if your old heater wasn’t a powered direct vent setup. That noise can sound even louder if the floors directly above the water heater are hard-wood. Sometimes simply putting an area rug down in the spot on the floor directly above where the water heater is located in the basement can really help absorb some of the vibrations that are causing the noise nuisance. But if the noise isn’t just that of a louder fan – say if the noise is more like a rattling or a tinkling – those would be indicative of other issues.
I have an American Standard hot water heater about 5-6 years old, looks like new, no leaking, but recently I hear what is a very light ssssssss sound for about 5 minutes then stops. I called the plumber who installed and said with that model when the elements kick on to heat up more water, this model does this? In all the years we’ve had this, never heard this before. He said another sign its going is the water is too hot, doesn’t seem to have changed, but that too can be hard to tell, its not like any member of my family is getting burned from being too hot. Is this on its way out, asking because I have the money now to replace it. Thanks
Hi Gloria, Good question. It sounds like you have an electric heater, so the hissing is likely a result of sediment build-up on the bottom of your heater and/or on the heating elements – a common side effect of heating hard water. (We describe the popping sound made by gas water heaters when this happens – electric heaters make a hissing or sizzling sound instead.) So ultimately, we suggest installing a water softener to solve the root cause and prevent further problems. Then, you have a couple of options to address the current state of your hissing water heater. You could simply try to replace the heating elements themselves, which may be cheaper than replacing the whole unit. (That’s one benefit an electric water heater has over a gas heater!) Since you just noticed this issue, you could also attempt to drain & flush your heater, and try to manually clean out the sludge buildup. However, that is a time consuming process that can also lead to other plumbing issues, because you’re dislodging sediment buildup that can then get carried throughout the rest of your plumbing system, potentially clogging up other fixtures. And, if you hire a plumber to do it, the labor cost could exceed the cost of a new residential heater. Or you could proactively replace the heater as you originally thought. However, with any of these options you’ll still have a recurring issue of sediment building back up unless you solve the root problem and install a water softener first. We hope this helps. Good luck!
Thank you for getting back to me. Only 3 weeks ago, we installed a Culligan full house water softening system. This noise only started “after” the system was installed and I even wondered, is this noise happening because of the water softening system now working in the electric hot water heater? OK, should I still be concerned, or do you suggest calling my plumber to flush the hot water heater. Again, its only about 5 years old.
Many thanks
Hi again Gloria. The fact that the noise began right after you got your softening system installed does seem like there’s a correlation. Generally, a softener should not cause your water heater to sound differently as a rule, so I’d actually suggest calling Culligan to investigate the situation, to make sure all the connections are setup right. (Though I should also ask, are you certain the noise is coming from your water heater and not from the new softener or the nearby pipes? Softeners do make noise during their regeneration process – though that shouldn’t be a hissing sound, nor should it happen very often.)
If it is definitely the water heater hissing, and if Culligan can’t identify anything else that could be triggering the noise, then contacting your plumber to at least inspect the heating elements and tank for sediment buildup is still a good idea. Especially now that you have a softener, if you end up replacing the heating elements and/or flushing the tank, you’ll be starting with a relatively clean slate & should get plenty more life out of that heater going forward, and it will run more efficiently too. For a residential heater that’s only 5 years old, preventative maintenance is definitely worth trying before just replacing it, especially if it’s working correctly otherwise.
My gas water heater is almost 10 years old and was working fine until a week ago when I noticed it backdrafting. You mentioned to check to see if the flame is yellow.I did this and I can’t really see a yellow flame. My vent is installed correctly as there were no problems before.Is it possible that it isn’t burning hot enough and even though the flame appears normal that if I replace the water heater it will correct this? Thanks for this informative site.
I replaced the water heater and it is working fine. Everything was installed correctly and the flame wasn’t yellow but wasn’t hot enough, I guess , but working now with no backdraft.
Hi George, We apologize for not responding to your original comment, but we’re happy your new water heater is working without issue. And it sounds like you made the right decision! Since your old heater was back-drafting but wasn’t producing a visibly yellow or orange flame, then most likely the flue pipe inside the unit was either clogged with internal soot buildup or was damaged in some way, limiting the air flow through the flue resulting in the back-drafting. Flue pipes can sometimes crack or rust away over time and once the flue itself is compromised there’s not much that can be done to fix it other than replace the whole water heater. Thanks for the comments & the update on your situation – we wish you many years of good hot water with your new water heater!
my water heater is about 10 yrs old the and is piped to drain into my crawl space the other night I kept hearing my sump pump kicking on and it hasn’t rained in over 2 weeks so I went into the laundry room where the hot water heater is and I could hear water dripping out of the overflow pipe and it was very hot so I checked the relief valve and released some pressure and it seemed to help I also lowerd the temp down is this a sign that it is going bad or maybe a bad vavle
Hi Mark, Good question. From your description, it sounds like it’s likely a bad T/P valve. We definitely recommend changing that out, because once the valve begins leaking consistently, it needs to be replaced for safety. And that’s a relatively inexpensive part to replace, especially compared to the cost of a new water heater. We suggest calling a professional if you don’t know how to safely change this valve yourself, as there’s specific steps to follow to ensure it’s done properly. If you still experience the same issues after replacing the T/P valve, then it might indeed be the end of your heater and it’s definitely time to call a plumber. We hope this helps, and good luck!
Thank you for this article..our electricity was off for several hours yesterday when it was turned back on the electric hot water heater started popping so loudly , it was scary. I was about to google the problem and it suddenly started gushing water. The heater is located in our hallway with hardwood floors. I immediately turned the water valve off so flooding wasn’t too bad. I had never experienced this in all my 64 years. Will be getting new hwh tomorrow. Thank you so much ,now I understand the problem and what to do to prevent future damage.
Wow, what an experience! Unfortunately, sometimes all it takes is a simple event like a power outage to trigger a problem like that. Sounds like the sediment buildup in your tank was probably keeping the weld sealed – for who knows how long – but with the longer power outage the water inside the heater got cold for long enough that the metal contracted and the sediment shifted. So once the water heater came back on, the sediment started popping as it was heated and the metal expanded again and just like that the seal finally gave out. So sorry you had to go through that, but thanks for sharing your story! I’m glad our article was able to provide peace of mind during a stressful situation. Good luck with your replacement water heater!
I’ve noticed a lot of dripping water coming from my water heater! I thought it was just the pipes! Thank you for letting me know it might be a sign that I need to repair my water heater. I’ll make sure to take care of it as soon as possible. Thanks!
I had no idea that it was so important to regularly check your water heater. Like you explained, small leaks can lead to very big problems. I imagine that without checking your water heater regularly it would be very hard to spot those small leaks until there is mold growing and it is almost too late. Now that I know the importance of checking the water heater I will make sure that I do so more frequently.
You mentioned that “understanding where your water heater is leaking FROM matters.” That is something that we are a bit concerned about right now. We noticed that our water heater was leaking a couple days ago but can’t figure out from where. We will have to keep this information in mind and hopefully be able to fix whatever isn’t working properly.
Thanks for reading, Danni! We’re glad you found this useful. Yes, identifying the leak source is pretty vital. We wish you luck in finding your source and hope it’s one of the easier situations for you.
Nice piece of information shared. Thanks.
So glad you found it helpful – thanks for reading!
My water heater has been dripping water recently. I don’t know what that means but I am happy to know that I should get it looked at. I like that you mention the differences for the leaking so that I can explain it to the plumber when I call him!
My hot water heater makes a sssssss sound like it is relieving pressure. Is this dangerous? What can I do ?
That’s a noise that should definitely be investigated by a professional in person, because it could mean different things. It could indicate that your heater has developed a small leak at the bottom – water dripping onto the burner can cause a flash boil which makes a noise similar to what you’ve described. Unfortunately, if you have a leaking water heater, it will need to be replaced and it’s best to replace it before that small leak gets bigger and the whole bottom drops out. Alternately, water heaters do have an important part called a T&P (Temperature & Pressure) Valve, designed specifically to relieve excessive pressure as a safety precaution. However, the noise you describe is not a noise that valve should make, so if the noise is originating from here you need to call a plumber to inspect your heater for trouble that could be causing a pressure buildup (which yes, can be dangerous), and/or to determine if that valve needs to be replaced. In either case, your concern is valid and we recommend having a professional inspect your equipment as soon as possible to prevent a bigger issue. Good luck!
Antonia, here’s our best guess: When you say “located behind a removable metal guard covering this area,” it might mean there’s a gasket leak in that area and the water may be combining with the insulation of the tank. The insulation (especially on older equipment) when wet can become sticky.
This is just a guess though. We officially recommend you seek the advice of another plumber who can do a more thorough inspection on site.
you mention a “honeycombed mineral sludge”. my water heater seems to be “spitting out” a sweet sticky substance at the bottom where the valves and other wires are located behind a removable metal guard covering this area. my plumber has never seen anything like it and thinks that i may have spilled something sugary on the heater. (not likely at all) what is this substance and why is it coming out of my water heater?
can you tell me if your pipes seem to be under pressure and you turn off the water suddenly and it makes a loud sound, would that cause the water tank to fail.