🔧 Repair or Replace
Water Heater Trouble: Repair It or Replace It?
Age, the type of failure, and what a repair costs relative to a new unit are the three things that decide it.
Marcus Ibe · Oct 15, 2026 · 6 min read · 5 steps
A tank water heater typically lasts 8 to 12 years. Tankless units often last 20 years or more. When something goes wrong, the age of the unit is the first thing to check — it is printed on the label or encoded in the serial number.
Some problems are cheap fixes on a unit with years of life left. Others are a clear signal to start shopping.
Problems that are usually worth repairing
These parts are inexpensive and replaceable on most units:
- Pilot light that will not stay lit — often a thermocouple or flame sensor
- No hot water on an electric unit — often a failed heating element or thermostat
- Dripping temperature-and-pressure relief valve — the valve itself may need replacing, but have the pressure checked too
- Leak at a fitting or valve on top of the tank
Problems that mean replacement
Water pooling under the tank from the tank itself almost always means the inner lining has corroded through. There is no practical repair for that. Rusty water coming only from the hot tap, combined with an older unit, points the same way.
Rumbling and popping noises come from sediment build-up. Flushing can help a younger tank, but on an older one it is a sign the end is approaching.
The 50 percent rule
A common rule of thumb: if the repair costs more than half the price of a new installed unit, and the heater is past the middle of its expected life, replace it. You avoid paying for a repair on a unit that will fail again soon.
If you are replacing, think about the next 15 years
A like-for-like tank is the cheapest and quickest option. But it is worth comparing a heat-pump water heater or a tankless unit, which cost more up front but can cut running costs. Check for local rebates, and ask the installer whether your electrical panel or gas line needs upgrading.
Extend the life of the next one
Flush a tank heater once a year to remove sediment, and ask a plumber to check the anode rod every few years. That sacrificial rod corrodes so the tank does not; replacing it on time can add years to the heater’s life.
This is general home-maintenance information, not professional advice. Building codes, permits, and safe practices vary by location — consult a licensed contractor, electrician, or plumber for work beyond your experience.