Almost nobody calls us the first time they run out of hot water. They call after the third or fourth cold shower, usually with the same sentence: it used to last so much longer than this.
They're right, and it's worth saying plainly: a water heater that used to give you twenty minutes and now gives you eight has not suddenly shrunk. Something inside it is taking up room that used to hold hot water, or something has stopped heating it. Those are two very different problems with two very different bills, and you can usually narrow it down before anyone comes out.
The most common cause is sediment, and it is cheap to fix
Central Texas water is hard. Every gallon that goes through your tank leaves a little calcium and magnesium behind, and it settles on the bottom. After five or six years there can be several inches of it sitting in the bottom of a 40-gallon tank.
That matters for two reasons:
- The sediment takes up volume. A tank with four inches of scale in it is not a 40-gallon tank anymore.
- On a gas heater, the burner is underneath. It now has to heat through a layer of rock before it reaches any water, so the tank recovers more slowly between showers.
The tell is sound. A sediment-heavy tank pops, rumbles, or crackles while it heats, because water is getting trapped under the scale and flashing to steam. If your heater has started making noise it didn't used to make, that's your answer.
Flushing the tank is the fix, and on a heater that's been maintained it's straightforward. On one that hasn't been flushed in a decade, sometimes the drain valve clogs solid with the debris you're trying to remove — which is annoying, but still a much smaller job than a replacement.
If it went cold suddenly rather than gradually, look at the elements
Sediment is a slow decline. You notice it over a season, not over a weekend.
A sudden change usually means something electrical. Most residential electric heaters have two heating elements, an upper and a lower. If the lower element fails, the upper one still heats the top third of the tank, so you get hot water — just a lot less of it, and it runs out fast. That's the classic "I get exactly one short shower" complaint.
A failed element is an inexpensive part. Diagnosing which one, and confirming it's the element rather than the thermostat or the breaker, is the actual work.
On a gas heater, a sudden loss usually points at the thermocouple or the gas control valve instead. If the pilot won't stay lit, that's where to look.
Things worth checking yourself first
Before you call anyone, two minutes of looking can save you a trip charge:
- Check the thermostat setting. Somebody may have turned it down. 120°F is the normal setting; anything below about 115°F will feel like it's running out early.
- Check the breaker on an electric unit, and the pilot light on a gas unit.
- Check for a leak at the base of the tank. Standing water or rust streaks change the conversation entirely — a leaking tank is not repairable.
- Note the age. There's a date in the serial number on the label. Most tank heaters last eight to twelve years here.
If the tank is twelve years old and leaking, we're going to tell you to replace it. If it's six years old and rumbling, we're going to flush it. We'd rather tell you the cheap answer and have you call us again in four years.
When it's genuinely time to replace
Replacement is the right call when the tank itself has failed — a leak from the body of the tank, not from a fitting — or when the repair costs a meaningful fraction of a new unit on a heater that's already near the end of its life.
It is also worth a conversation if your household has grown. A 40-gallon tank that was fine for two people is not fine for four, and no amount of repair work changes that. In that case you're not fixing a broken heater, you're sizing a new one correctly, and that's a better use of the money.
What we'd do
If you're in Austin, Buda, Kyle, or Round Rock and you're not sure which of these you've got, call or text us and describe what changed and when. Gradual decline plus noise is almost always sediment. Sudden decline is almost always a part. We can often tell you over the phone which one you're looking at, and roughly what it costs, before anybody schedules anything.
That's the whole idea. You should know what you're buying before you buy it.