Replacement timing
How long do water heaters last?
A traditional tank water heater is commonly expected to last about 8 to 12 years. Tankless systems are often quoted at roughly 15 to 20 years or more with proper maintenance. Those are planning ranges, not expiration dates.
Age matters most when it is combined with another signal: leaking, repeated repairs, reduced hot-water performance, corrosion, or an expensive repair quote. A functioning 11-year-old tank does not automatically need replacement, but it is reasonable to know the replacement option before an emergency.
Typical planning ranges
| Type | Common planning range | What changes it |
|---|---|---|
| Tank water heater | About 8 to 12 years | Water quality, installation, maintenance, operating conditions, and tank condition |
| Tankless water heater | Often 15 to 20+ years | Maintenance, water quality, scale, usage, and serviceability |
How do you find the age?
Start with the manufacturer label. Look for the model and serial number, then use the manufacturer's serial-number lookup or support documentation. There is no single serial-number format that works across every brand.
Age alone is not the decision
The more useful question is whether keeping the current unit still makes sense. Put the repair cost, age, current condition, reliability, and replacement option next to each other. If the tank is sound and the repair is limited, repair may still be reasonable. If the tank is leaking or the unit is creating repeated uncertainty, replacement becomes easier to justify.
Read the repair-or-replace guide.
When should you get a replacement quote before failure?
- The unit is already in the later part of its expected service life
- You are seeing intermittent leaks or corrosion
- Hot-water performance is changing
- You have already paid for repeated repairs
- You want time to compare tank, tankless, or heat-pump options without emergency pressure
Rheem water-heater lifespan guidance and State Water Heaters repair-or-replace guidance, checked September 2026.
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