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.

Water System

  • 1
    It sure sounds like you have some blockage in the pipes AFTER the pressure tank. Since the pressure at the tank is good, and it stays stable after you open a tap, you should get good flow as the water is delivered from the tank and the pump eventually comes on. But you are seeing low pressure at the tap with good pressure at the tank.
    – jwh20
    Commented Mar 24, 2020 at 16:34
  • 3
    Since it started shortly after you broke a pipe, I would think you got debris into the pipe and it worked it's way to a valve or ? and is blocking most of the flow. If you have an expansion tank on the water heater in the house, that would allow the lines in to house to slowly get up to pressure, but would normal pressure would only last until the pressure dropped in the expansion tank. Would it be possible to "reverse flush" your supply line? A diagram of your entire water system would help. Commented Mar 24, 2020 at 16:57

3 Answers 3


After trying everything I could, attaching a hose to the farthest water line in the house to a hose and flushing water back out to check for blockages. Changing or cleaning all the filters. Bypassing every part of the system I could. I finally took the step of replacing the pressure tank and entire T assembly, and that fixed it.

I have no idea what was wrong with the pressure tank though. I checked for water in the air compartment, and there was none. The pressure gauge always seemed to be working, and showed normal pressure drop with usage and increase when the switch turned on. There were no blockages in the T or pressure tank that I could find.

So I never found the actual problem, but it has to be something with the pressure tank. It looks like the answer to my issue was to just replace the pressure tank.

  • Please give yourself a check mark since this solved your problem (even though you don't understand why it did).
    – FreeMan
    Commented Jan 11, 2021 at 12:00

I think that you have a partial 'blocker' in your water line. It might be something that get into it while doing the pipe repair. Since it's affecting all of your house, it must be in the part of the piping that is common to all of them, so somewhere between there and your pressure gauge. Its most likely somewhere that is most likely to trap it, so to speak. Is there a valve somewhere? That would be an excellent place for something to get stuck. Or at a corner. Or reducer in diameter.

I would check for valves and if you find one, open and close it several times and see if that shakes something loose.

My next thought is that to fix your going to have to go a'hunting to find the location of the blockage. Tap into the pipe somewhere logical to test if that spot also losses pressure. If it does or doesn't will tell you on which side of the tap the blockage is located. I'm not a plumber, so they might have other, better tricks for this process. Or a tool that you can use to clean the pipes much like that is done with the waste pipes.

  • As I mentioned in my update, I took apart everything in the system from just before the break to where it couldn't get past, the spin down filter. It did its usual works fine for awhile, and then starts to lose pressure. I am starting to think that maybe something else happened right around the time of the break, and it was all just a coincidence. But I am grasping at straws at this point
    – ursasmar
    Commented Mar 26, 2020 at 14:51

When you replaced your pressure tank, or bladder, you likely also inadvertently replaced your Water Pump Pressure Control Switch. If the Water Pump Pressure Control Switch on the prior bladder tank were faulty or the cut in- cut out ranges were improper set, that could account for the original water pressure problem you were experiencing. Good job on replacing the Water Pump Pressure Control Switch and bladder.

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