For most homeowners, hot, running water is a luxury they don’t think twice about. The average person uses warm water up to 20 times per day in their home. However, homeowners should always be proactive in maintaining their water heaters. But when to replace the water heater altogether? The manufacturer’s average suggested lifespan for a traditional water heater is between eight to 12 years. A tankless water heater can last up to 20 years before it needs to be replaced. Regardless of what type of water heater is installed, over time, it will corrode with age, and it’s essential to monitor it for any of the below issues, especially if it’s in the second half of its lifespan.
I’ve seen firsthand how easy it is to overlook water heater maintenance—most of us don’t even think about it until something goes wrong. To add some context, corrosion in water heaters often stems from the constant exposure of the tank’s interior to water, which can lead to rust or mineral buildup. According to a 2023 study by the U.S. Department of Energy, about 15% of a home’s energy use goes to water heating, so keeping your system in good shape can save you money. My tip? Set a calendar reminder to check your water heater annually, especially if it’s over five years old. Flushing the tank every year or two can help remove sediment and extend its life, but you’ll want to keep an eye out for the warning signs below to know when it’s time to say goodbye to your old unit.
The Water Looks Cloudy, Sandy, or Rusty
One common issue older water heaters have is producing discolored water. There are many reasons why this could occur, and it may not mean the water heater needs to be replaced. When corrosion happens, rust builds and can leak into the water supply. This leads to discolored water coming out of the faucets. Before jumping to conclusions about the water heater, homeowners should run cold tap water for a few minutes. If that water is also rusty, it may mean the issue is within the pipes, not the heater. If it is not rusty, it may be time for a new water heater. Sometimes water may be cloudy or sandy, caused by a buildup of sediment in the heater tank. Homeowners can rectify this issue by draining the contents of the tank and clearing out the sediment. However, if the water continues to run sandy or cloudy, the heater must be replaced.
Discolored water can be a real headache, and I’ve dealt with it in my own home. The science behind it is pretty straightforward: minerals like calcium and magnesium in hard water settle at the bottom of the tank over time, forming sediment. Rust, on the other hand, signals that the tank’s protective lining might be wearing out. A quick trick I’ve learned is to check the anode rod—a sacrificial piece of metal that attracts corrosion to protect the tank. If it’s worn down to a nub, replacing it (about $20-$50) can sometimes buy you more time. But if the tank itself is rusting, you’re looking at a replacement, which can cost anywhere from $500 to $2,000 depending on the type and size. Regular flushing can help, but if you’re seeing persistent cloudiness even after a flush, it’s a sign the tank’s days are numbered.
You’re Not Getting Enough (or Any) Hot Water, but Your Heating Bill Has Gone Up
The most obvious reason to get a new hot water heater is a lack of warm water getting to the house. This can mean the water isn’t as hot, the periods of hot water don’t last as long, or there is no hot water altogether. The issue worsens if the heating bill is going up at the same time. There may be no or less hot water because there is an issue with the electrical thermostat. On average, a home should have the thermostat set between 120 and 140 degrees. If the thermostat is readjusted and the hot water returns, then there’s no reason to replace the heater. The lack of hot water could also result from a broken heating element within the water heater. A plumber can easily fix this issue, get the parts needed, and restore heating functions within a few hours. However, the components required for older water heaters may not be as readily available, and in some cases, it may be just better to replace the system overall.
I’ve had mornings where the shower goes cold halfway through, and it’s not a fun way to start the day. When your water heater starts slacking and your energy bill creeps up, it’s often because the system is working harder to compensate for issues like a failing heating element or sediment buildup reducing efficiency. Data from Energy Star suggests that a new, energy-efficient water heater can cut water heating costs by up to 50% in some cases. Before you rush to replace it, though, try tweaking the thermostat—120 degrees is usually plenty hot and safer for preventing scalding. If that doesn’t work, a plumber’s visit (around $100-$200) to replace a heating element might do the trick. But if parts for your model are hard to find, it’s a clue that your heater is outdated, and a new one might save you more in the long run.
The Water Heater Is Making Strange Noises
As water heaters get older, the rumbling noises they make to heat up water might get louder. This can be due to various reasons, which may be more significant signs the heater needs to be replaced. As mentioned above, sediment can build up over time at the bottom of the tank. The noise caused by sediment buildup is the sound of the hardened sediment banging against the tank. If not flushed out, the sediment will grow harder and thicker along the floor and start to wear the water heater down. This will make the heater more inefficient and accelerate the damage to the tank. Homeowners should check for this problem as soon as they hear any unusual noise from their water heater. Taking early action can prevent long-term damage and extend the heater’s life if it’s not yet time for a water heater replacement.
Those loud pops and rumbles from a water heater can sound like a mini construction site, can’t they? That noise usually comes from sediment getting heated and causing tiny explosions of steam in the tank. I learned this the hard way when my old heater started sounding like a kettle about to blow. Flushing the tank can sometimes quiet things down, and it’s a job you can DIY with a garden hose and about an hour of time. If the noises persist, though, it’s a sign the tank’s interior is taking a beating. A 2024 plumbing industry report noted that sediment-related issues account for nearly 30% of water heater failures. Regular maintenance can delay the need for a new unit, but if your heater’s making a racket and it’s over 10 years old, start budgeting for a replacement to avoid a bigger mess later.
You’ve Noticed the Water Heater Is Leaking
At the end of their life span, hot water heaters tend to leak around the floor of the tank. This could potentially lead to minor to significant property damage for the homeowner. A leak in a water heater tank could mean it’s time to replace it. Leaks are usually caused as the result of expansions to metal in the tank. These expansions occur over the multiple heating cycles of the tank’s life. Fractures may occur because of this expansion, leaking water at the height of each heating cycle. Sometimes, the leak may be minor enough to fix, but this is only delaying the inevitable replacement.
Spotting a puddle around your water heater is never a good sign—I had a small leak once that turned into a soggy basement floor before I caught it. Leaks often happen because the constant heating and cooling cycles stress the metal, causing tiny cracks. According to plumbing experts, even a small leak can escalate quickly, potentially causing water damage that costs thousands to repair. If you catch a minor leak early, a quick patch might buy you a little time, but it’s like putting a Band-Aid on a broken pipe. My advice? Keep a close eye on the area around your heater and consider a replacement if you see any moisture. Newer models, especially tankless ones, are built with better materials that resist corrosion longer, which could save you from this headache in the future.
You’ve Called in Multiple Repairs in Recent Years
Water heaters can be sensitive and may need to be repaired frequently. If a homeowner finds themselves calling in a plumber on multiple occasions for a hot water heater repair, it may be worth it to replace it altogether. Water heaters are getting more sophisticated every year. Depending on which heater is purchased, it could last longer and even provide some efficiency for electricity bills.
Calling a plumber every few months for the same water heater feels like throwing money into a black hole. I’ve been there, and it’s frustrating when you realize the repair costs are adding up fast. Modern water heaters, especially Energy Star-certified ones, can reduce energy use by up to 20% compared to older models, based on recent industry data. If you’re sinking $200-$500 into repairs every year, a new unit (starting around $800 for a basic model) could pay for itself in energy savings and reliability within a few years. Plus, newer models often come with better warranties—some up to 12 years—which gives you peace of mind. If your repair bills are piling up, it’s time to weigh the cost of a new system against patching up the old one.
Your Water Heater Is Old, or You’re Not Sure When It Was Last Replaced
Often, when a person buys a house, the water heater was installed years ago. If the previous homeowner doesn’t have any documentation, it can be challenging to gauge how old the water heater is and when it needs to be replaced. Luckily, the serial number on the water heater typically includes a manufacturing date. In most cases, the first letter of the serial number will indicate the month it was manufactured, starting with “A” for January, leading all the way to “L” for December. The next two numbers will indicate the year it was made. For example, if a serial number starts with “C19” the water heater was manufactured in March 2019. Even if none of the above problems are occurring, if a water heater is over 10 years old, the homeowner should have it maintenanced. It’s best to hire a professional plumber who can let you know if there are any issues with the heater and give their professional opinion about when they should replace it.
Not knowing your water heater’s age can feel like a bit of a mystery, especially in an older home. I remember moving into a place and having no clue how long the heater had been chugging along. Checking the serial number is a lifesaver—mine started with “F15,” so I knew it was from June 2015. If your heater’s pushing a decade or more, it’s worth getting a pro to take a look. A 2024 survey by HomeAdvisor found that water heaters over 10 years old are 80% more likely to fail unexpectedly. Regular maintenance, like checking the pressure relief valve or inspecting for corrosion, can catch problems early, but if your heater’s from the early 2010s or older, start planning for a replacement. A plumber’s inspection (usually $100-$150) can give you a clear picture of whether it’s time to upgrade.