What water heater problems can be repaired?
Most problems outside the tank itself can be fixed, including thermostats, heating elements, the temperature and pressure relief valve, sediment buildup and loose connections. These are the repairable faults listed in A.O. Smith’s repair-or-replace guidance.
Not enough hot water is often a thermostat or element. A dripping relief valve can be a pressure problem rather than a failing tank.
When should a water heater be replaced instead?
Replace it if the tank itself is leaking, it's more than about 10 years old, or the repair costs more than half the price of a new heater. The 10-year guide comes from A.O. Smith and the 50% rule from Rheem.
A leak from the tank body usually means internal corrosion. A.O. Smith says a corroded or cracked tank is normally a replacement, not a repair. Our water heater replacement cost guide covers what that costs in Knoxville.
How much does water heater repair cost?
HomeServe’s Tennessee water heater figures put the average diagnosis at $101 and the average repair at $479. The average replacement is $1,387.
The final price depends on the part, the heater type and how easy it is to reach. Ask for the price before work starts.
What should I do if my water heater is leaking?
Turn off the cold water supply to the heater, then turn off its power at the breaker (electric) or set the gas control to “off” or “pilot” (gas). Then call a plumber.
A leak from a fitting or valve is often a quick repair. A leak from the bottom of the tank usually isn't. If water is spreading, treat it as an emergency.
Should I switch to a tankless or heat pump water heater?
They cost more to install but less to run. The U.S. Department of Energy says tankless heaters are 8%–34% more efficient than tank models and heat pump heaters can be 2 to 3 times as efficient as standard electric ones.
The federal tax credit for heat pump water heaters only applied to equipment placed in service before December 31, 2025, according to the IRS. Weigh the upgrade on running costs alone.
Frequently asked questions
How long does a water heater last?
Manufacturers Rheem and A.O. Smith put a standard tank at about 8–12 years. The Department of Energy says 10–15 years, and about 20 for tankless.
Why is my water heater making popping noises?
Usually sediment on the bottom of the tank. Rheem recommends flushing the tank once a year to remove it.
Updated 2026-10-07