A traditional tank water heater lasts 8 to 12 years. A tankless water heater lasts 15 to 20 years or more. Replace your unit when it hits 10+ years and shows signs of failure. Replace it when repair costs more than 50% of a new install. Or replace it when the tank itself leaks. Repair makes sense if your unit is under 8 years old and the problem is a single component.
How long does a water heater last? The short answer is 8 to 12 years for a standard tank and 15 to 20 years for a tankless. The longer answer depends on three things. Your water source, how often you flush the unit, and the type of failure you are seeing. Some homes in older parts of Cary and Raleigh still have water heaters from the early 2000s. Others fail at year 7 from skipped maintenance.
Unlimited Plumbing has installed and replaced water heaters across the Triangle since 2010 under North Carolina license #30294. Below is how long each type really lasts. Plus what kills them early and the math for deciding repair vs. replacement.
How Long Does a Tank Water Heater Last?
A standard tank water heater lasts 8 to 12 years on average. Gas units sit at the lower end of that range. Electric units often push a little longer because they have fewer moving parts. The U.S. Department of Energy puts the typical range slightly higher at 10 to 15 years with proper maintenance.
Three things shorten that lifespan in the Triangle:
- Skipped annual flushes. Even on Cary’s soft municipal water, trace minerals settle at the tank floor. Sediment hardens over years, traps heat, and stresses the tank wall.
- Old anode rods. The sacrificial rod corrodes first to protect the tank. Once the rod is gone, the tank itself starts to rust from the inside.
- Well water in outlying areas. Homes in rural Johnston, Chatham, or Harnett County often have harder well water. The extra mineral load speeds up sediment buildup.
Is your unit 10 years or older? If you have never flushed it or replaced the anode rod, it is on borrowed time. Most homeowners do not realize the rod even exists until a plumber points it out.
How Long Does a Tankless Water Heater Last?
A tankless water heater lasts 15 to 20 years or more with regular descaling. Tankless units run on demand instead of holding heated water. That means less constant stress on the heat exchanger and no tank to rust out.
Tankless units have their own maintenance needs. Mineral buildup forms scale inside the heat exchanger over time. Annual descaling with a vinegar or commercial solution keeps efficiency high and the unit running long. Homes on well water need descaling more often than homes on Cary’s soft municipal supply. Our tank vs. tankless guide covers the cost and efficiency tradeoffs in depth.
What Makes a Water Heater Wear Out Faster?
How long does a water heater last? The answer depends on the wear it takes. Five things cut years off the average lifespan. Most are preventable.
- Skipped maintenance. Skipping the annual flush and the anode rod check is the single biggest cause of early failure.
- Sediment buildup. Even soft municipal water carries trace minerals that coat the tank floor over years. Well water builds sediment far faster.
- High thermostat setting. Anything over 140 degrees stresses components and speeds up corrosion.
- Undersized unit. A heater that runs constantly wears faster than one sized for the household.
- Poor installation. Loose fittings, missing expansion tank, or incorrect venting all shorten lifespan.
Just bought a home in Cary or Raleigh? Schedule a flush and an anode check if you do not know the service history. Our water heater service in Cary covers both.
What Are the Signs Your Water Heater Is Dying?
Common signs your water heater is dying include rusty hot water and rumbling or popping sounds. Watch also for water around the tank base. Fluctuating temperature and rising energy bills also point to a failing unit. Any one of these on a 10-year-old unit means the clock is ticking.
Watch for these in particular:
- Water pooling at the base. A tank leak almost always means replacement. You cannot patch a tank safely.
- Rusty or cloudy hot water. Internal corrosion is leaking iron into your hot water lines.
- Rumbling or popping. Hardened sediment knocks against the tank floor as the burner runs.
For the full deep dive, see our post on the 7 warning signs your water heater is about to fail.
What Is the 50% Rule for Water Heater Repair vs. Replacement?
The 50% rule says to replace your water heater when the repair quote exceeds half the price of a new install. The same rule applies when the unit is approaching the end of its expected lifespan. At that point, putting more money into an old unit just delays the inevitable.
Here is the math in practice. A new tank water heater in Cary typically costs $1,500 to $3,500 installed. Half of that range is $750 to $1,750. If your repair quote is above that line, especially on a 10+ year old unit, replacement wins. Our full breakdown of water heater replacement cost in Cary covers the numbers in detail.
Common repairs that are usually worth doing on a unit under 8 years old:
- Thermostat replacement: $150 to $300
- Heating element (electric): $200 to $400
- Anode rod replacement: $200 to $400
- Pressure relief valve: $150 to $350
Common repairs that usually mean replacement is smarter:
- Tank leak from the body of the tank
- Failed gas valve on a 10+ year old unit
- Multiple repair calls in the same year
- Any repair over $800 on an aging unit
Should You Replace a Water Heater That’s Over 10 Years Old?
Yes, plan to replace a water heater that is over 10 years old. Replace it even if it still seems to work. Past 10 years, the risk of a sudden tank failure rises sharply. A failed tank can dump 40 to 50 gallons of water onto your floor in under an hour.
Planned replacement gives you three things an emergency replacement does not:
- Choice. You can compare tank, hybrid, and tankless options at your own pace.
- Price. No emergency-rate markups.
- No water damage. No soaked drywall, ruined flooring, or insurance claims.
If your unit is 10 years or older and showing any warning sign, get a quote now. Replacing on your schedule beats replacing at 2 a.m. on a Sunday.
Ready to Replace or Inspect Your Water Heater in Cary?
How long does a water heater last in your home? The honest answer is: as long as you stay ahead of it. Unlimited Plumbing has served Cary and the Triangle since 2010. We flush tanks, replace anode rods, and install new units of every type. No extra charges for nights, weekends, or holidays. Call 919-300-0092 or contact us to schedule. We can often quote a replacement the same day.