Start with the symptom
Common Water Heater Problems
Which situation is closest to yours?
Hot water that runs out too fast
On an electric tank this usually means the lower heating element has failed, so only the upper portion of the tank is heating. It can also mean the tank is undersized for how the household actually uses hot water, or that sediment has reduced the usable volume.
Sediment is worth taking seriously here. Central Texas water is hard, and accumulated scale genuinely reduces capacity over time. If the unit has never been flushed, that is a plausible contributor — the maintenance page covers what flushing does and when it stops helping.
Popping, rumbling, or a tankless error code
Popping or rumbling on a tank unit is sediment. Water trapped beneath a hardened mineral layer flashes to steam and forces its way out. Early on, flushing helps. Once the deposit has hardened, it often cannot be removed.
An error code on a tankless unit is more useful than it looks — write it down before clearing it. Codes are manufacturer-specific and point directly at the fault, which shortens diagnosis considerably. Scale-related codes are common in hard water when descaling has been skipped.
If you smell gas, see smoke, or suspect a combustion or electrical hazard, leave the area and contact the appropriate emergency service or utility. Natural gas in Pflugerville is supplied by Atmos Energy across the great majority of the city — the emergency line is 866-322-8667 — and by SiEnergy in unincorporated areas that carry Pflugerville addresses, on 888-468-7007. Check which one bills you before you need it. Make that call before calling anyone else.
What happens after you identify the symptom
Knowing the symptom does not diagnose the unit — that takes someone looking at it. What it does is make the first conversation faster and let you tell whether the answer you get accounts for your situation. From here, the repair page covers what tends to be fixable, and the repair or replace page covers the decision itself.
Common questions
What is the most common problem with a water heater?
On electric units, a failed heating element or thermostat. On gas units, a pilot or thermocouple failure. Across both, sediment buildup is the underlying condition that shortens life and causes the rumbling most people notice first.
Who do I call if my hot water heater is not working?
A licensed plumber. Before calling, two checks take a minute: on an electric unit, look at the breaker; on a gas unit, check whether the pilot is lit. Those resolve it often enough to be worth doing first.
Should I turn off my water heater if something seems wrong?
If it is leaking, yes — close the cold water supply valve and switch off the breaker or turn the gas control to off. For a unit that is simply not heating, shutting it down is not urgent, though it does no harm.