As soon as we returned from an 8-day vacation last month, I noticed a substantial drop in showerhead water pressure. It's been like that ever since. And there seems to be a much longer delay between the times when the well pump kicks in to boost the pressure than before the vacation. Our other water fixtures do not appear to be affected as much.
The incoming water pressure is unchanged: about 35 psi coming into the pressure tank from the well, which has a 3/4 hp submersible pump. No water leaks are visible under the tank or under the 50-gallon electric water heater. I haven't checked the pressure of the tank yet. The iron-filtration system appears to be working normally (when it gets plugged up it can cause problems). It is connected downline from the pressure tank.
The pressure tank is more than 11 years old. But before I can determine that to be the problem, I need to learn more about it.
Question: Why would the showerhead pressure drop so much during several days of nonuse? And what should I be looking at for clues to solve this problem?