I have well water and the main pipe bringing the water from the well into the house had leak. The pipe was replaced with a new pipe about a month ago.

Since then, the water pressure has been dropping gradually. The well guy came in yesterday and he told me that it was the filter in the line that got clogged up with debris. I replaced the filter again - I had put a new filter after the pipe was replaced-- and pressure is better that after the pipe replacement, but not as good as before. The well guy mentioned that if the problem persists after replacing the filter, it might be the tank might gone bad and it needs to be replaced. He looked at the tank which is 4 year old and there is no leaks, no rust, no scratches, nor any signs that would indicate a bad tank.

My question is: Considering the tank looks in good condition, how does the reservoir tank affect the pressure into the house?

I am by no means a plumber, but other than having leaks, I don't understand the role the tank plays on the water pressure flowing through the pipe. Or is the well guy trying to pull a fast one?

  • Not all workers are “trying to pull a fast one”, some want to help... hope your well guy is not on here and recognizes you...
    – Solar Mike
    Aug 16, 2019 at 5:19

1 Answer 1


The tank has a bladder inside the bladder holds the water on the outside of the bladder( inside the tank is filled with air) . With the tank empty of water we normally pressurize the air to a few pounds less than the pump turn on pressure. So if your pressure switch is set for 40-60 it turns on at 40 psi and when it reaches 60 it turns off in this case we Would pressurize the tank 36-38 psi. This pressure pushes most of the water out of the tank with out the pump needing to start until the pressure drops to 40 psi. If the bladder had a leak and was not holding air the pump would short cycle rapidly and your pressure at your faucet has low flow. To check this turn your pump off drain the water out, using a tire pressure gauge measure the air pressure in the tank there is a small Schrader valve on the top of your tank.

if the pressure is below your cut in or pump on pressure by more than 5 psi it needs to be filled. A standard air compressor or bicycle pump can be used to pump it up. It may have a leak or got bumped when the pipe was replaced if it holds everything should be back to normal. Some manufacturers do make replacement bladders but seeing that they are not much cheaper than a new tank and a new tank will have a warranty I usually go new tank but have purchased bladders when they were reasonably priced. If the tank is holding its air charge the next thing is the pressure switch, I have had them freeze and not quite work correctly so it had to be replaced. If you don’t have a pressure gauge on your water line after the tank, it is a good idea to have one this way you can see when your pump is cycling and the pressure values. This should help you troubleshoot the system. Your plumber should have checked the air charge especially since the tank is only 4 years old, bladder based tanks at normal pressures have lasted over 20 and some closer to 30 years so I would check it out prior to replacing.


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