Tank versus tankless: the trade-offs
A tank water heater stores hot water in a large vessel and reheats it as you use it. A tankless water heater heats water on demand as it flows through, so it never runs out and takes up less space, but it costs more upfront and needs descaling in hard water.
Gas units heat faster and cost less to run in many homes; electric units are simpler to install where gas is not available. The right choice depends on your household size, fuel supply and budget.
Why water heaters fail
Most failures come from sediment buildup, a failed heating element or thermostat, a worn anode rod, or a leaking tank. Sediment insulates the element and causes overheating and energy loss.
In tankless units, scale in the heat exchanger is the common culprit. Regular flushing and descaling prevent most of these failures.
When to repair and when to replace
Repair a sound tank with a single failed part. Replace when the tank leaks, the unit is near the end of its expected life, or repairs are piling up. The same logic applies to pipes, drains and sewer lines: a localized fault can often be repaired, while a failing system may need replacement.
For a deeper look at how to weigh repair against replacement across your plumbing, see our guide on when repair is the right choice versus replacement.