Water heaters in this valley do not usually die of old age. They die of scale, and they do it years ahead of the warranty you were quoted at purchase.
That is not a defect and it is not a brand problem. It is what happens when you run very hard water through a steel tank and heat it every day.
What scale actually does
Heat water and the dissolved minerals in it come out of solution. They settle on the lowest surface in the tank, which on a gas heater is the exact piece of steel sitting directly above the burner.
Now the burner is heating a layer of mineral instead of heating water. The layer insulates. So the burner runs longer to get the same result, and the steel underneath it runs hotter than the designer intended, because the water that used to carry that heat away is on the other side of the deposit.
Steel that is repeatedly overheated fails. Usually at the bottom, usually as a slow seep before it becomes a puddle.
The other casualty is the anode rod. It is a sacrificial piece of metal whose whole job is to corrode so the tank does not, and in hard water it gets used up faster. Once it is gone the tank is on its own.
The rumbling or popping you hear from an older tank is not the burner. It is water flashing to steam underneath the scale layer. By the time a tank is talking to you, the damage is well along.
The maintenance that works
Three things, in order of how much they actually matter here:
- Flush the tank annually. Everywhere else this is advice people reasonably ignore. Here it is the difference of years. It takes about an hour and it removes the sediment before it packs down hard.
- Check the anode rod. Every few years. It is cheap to replace and replacing it is the single most effective thing you can do to extend tank life.
- Check your water pressure. A pressure regulator that has drifted high shortens the life of the heater along with every other fixture in the house. Most people have never had theirs tested.
If you have a softener, the heater benefits along with everything else. If you are weighing one up, the case for softening in this valley is stronger than the salesperson's pitch usually manages to make it — it is about what you are not going to replace over the next decade.
Tankless is not exempt
A tankless unit does not have a tank to accumulate sediment, which people hear as "no maintenance." What it has instead is a narrow heat exchanger, and scale in a narrow passage is a bigger problem than scale in a wide one. Tankless units here need descaling on a schedule. Skip it and you will be having a warranty conversation.
Repair or replace
Repair is usually right when the tank itself is sound and a component has failed — a thermocouple, a gas valve, a heating element, a thermostat. Those are service calls.
Replace when the tank is leaking. Not "consider replacing" — replace. Water coming from the body of the tank rather than a fitting means the steel has gone through, and there is no repair for that. Everything else on the unit could be brand new and it would still be finished.
The genuinely difficult case is the unit that is well into its second half of life and has just had something moderately expensive fail. Putting a few hundred dollars into a heater that owes you two more years is a real decision, and the honest answer depends on the age and how it has been maintained, not on a rule.
When not to call us
If you have no hot water and a gas heater, look at the pilot before you book anyone. If it is out, the relight instructions are printed on the side of the unit and they work. A relight is not worth a service call.
If it is electric and there is no hot water at all, check the breaker. Then check the reset button on the upper thermostat behind the access panel. Two things, both free.
If either of those fixes it and it stays fixed, you did not need a plumber. If the pilot goes out again within a week, then call — something is actually wrong, and now we know what to look at.