Yeah, flushing only gets you so far. I had a similar issue last winter—turned out my dip tube was basically disintegrated. Replaced it and suddenly the hot water lasted again. If you’ve got an electric heater, those elements are notorious for dying quietly too. Sometimes it’s just one thing, sometimes it’s a combo. Worth checking both before you start thinking about a new tank...
Not saying the dip tube or elements aren’t common culprits, but I’ve seen thermostats trip up more than folks realize—especially after a power surge or if the reset button’s been bumped. Sometimes it’s just a loose wire or a thermostat that’s gotten flaky with age. Ever check if both elements are actually getting juice? I’ve had heaters where only the top element was working, so you’d get a quick burst of hot water and then nothing... Not always obvious unless you test with a meter. Just throwing it out there—sometimes it’s not the tank at all, just a $15 part acting up.
Yeah, I’ve been burned by a bad thermostat before—literally got tricked into thinking my element was toast, but it was just the upper thermostat not kicking power down to the lower one. Wild how a tiny hiccup can throw off the whole system. I’d even add that sometimes those cheap wire connectors inside the panel get loose, especially if the water heater’s been worked on before… little bit of vibration over time and suddenly you’ve got an intermittent connection.
One thing I learned the hard way: don’t just trust the reset button popping out as your only sign. Had one where the button never tripped but the thermostat was still dead. Multimeter really is your friend here, even if you’re just poking around for continuity. Also, if your breaker’s been acting up or feels warm, that can sometimes be a clue too—power issues upstream can mess with things in weird ways.
Funny how it’s usually something simple, but it feels like you have to play detective every time the water goes cold.