09/15/2026
Hot water used to last through two showers. Now it doesn't.
Nothing in the house changed, so what did?
Three things affect how much hot water you actually get, and any one of them can shift without you noticing:
πThe temperature of the incoming water. Colder incoming water means your heater starts further behind, and you draw more from the tank to reach the same shower temperature.
πWhat's sitting at the bottom of the tank. Sediment builds up over the years and takes up space that used to hold hot water. That rumbling sound during heating is what it sounds like.
πHow long the tank gets to recover. A heater refills far slower than most people expect, so a shorter gap between showers changes the outcome even when nothing is wrong with the unit.
We explained how each one works and how to tell which is yours:
https://bens.plumbing/blog/running-out-of-hot-water-in-the-shower/