Purchased my home 8 months ago and one of the first things I did was replace the pressure tank, switch, and water softener, and added a new filtration system. Everything was running fine, but overall pressure was a bit low, so I adjusted the pressure switch, and all was good. About a month ago, I accidentally broke part of my water line, so I replaced the broken piece, and all was good, for about a week. At that point, pressure would fall off in the house rapidly. Just using a faucet would give about 10 seconds of full pressure, and then quickly drop to barely a trickle. Flushing a toilet would kill pressure at all faucets for minutes.
To diagnose the problem I would turn on a faucet and then go to the pressure tank. The pressure gauge was at 60, and would slowly lower, like normal, but the water was still a trickle at the faucet. So, I replaced the pressure switch. Drained the tank, cut power, checked that the pressure in the tank was 38, attached the new switch, turned it all on, and it filled without issue. I checked the faucets, and everything worked fine. Ran the shower and flushed the toilet, and there was negligible pressure drop in the shower. This lasted for about 24 hours before the same problem came back.
To make sure the issue wasn't my filtration system I ran a new line directly from the outlet of the pressure tank into my cold water lines, bypassing the filters. Same issue as before, little to no pressure after a few seconds of use. So I turned the power off, drained the lines and pressure tank, rechecked the pressure in the tank, turned it all back on, and it again it worked properly for about 24 hours before returning to its old ways.
This behavior has me confused, and I am now unsure of what to try next, or check next, or what to look in to. Any help would be appreciated.
Update: I took apart the my system from the check valve to the spin down filter, flushed all of that out, then put it all back together again. I got the same 24 hours of normal use, and now it has gone back to its old ways, but, the pressure doesn't drop as much, and it recovers more quickly from a toilet flush than it did before.
And for reference, the initial break in the line happened between the pressure tank and spin down filter.