Low pressure. Starts out high

[Jimbo Furgeson]

I am trying to diagnose a low water issue on my system. When first running water it comes out fine for a few seconds then slows to half of what it should be. The gauge on my pump is showing the correct pressure, kicks on at 30PSI and off at 50. The PSI on the pressure tank is matches what the gauge on the pump reads.

The low pressure is happening to all faucets, spigots, and toilets. They all get a second of good pressure and then drop fast.

Any suggestions on troubleshooting this?

 

[Boycedrilling]

When the pump shuts off at full pressure, turn th breaker off. Turn a faucet on and see how much water you get before you have zero pressure. Measure the pressure in the tank. Tell us what you found.

 

[Sponsor]

 

[VAWellDriller]

Got any filters on system that could be clogged?

 

[Jimbo Furgeson]

When the pump shuts off at full pressure, turn th breaker off. Turn a faucet on and see how much water you get before you have zero pressure. Measure the pressure in the tank. Tell us what you found.

Took 20 or 30 minutes to get to zero. Pressure in tank is at 29 empty. There are no filters that I know of. Tank is a "one way in and out" type

 

[Boycedrilling]

You have a restriction in your system somewhere blocking the flow. When you are not using water, the pressure equalizes. But when you start using water the restriction will not let the water flow fast enough to maintain pressure.

Clogged filter like VAWellDriller suggested?
I have seen the bladder in a pressure tank block the outlet
Pipe restricted from corrosion?
Did somebody adjust or bump a valve handle?

It’s going to be a process of elimination to find the restriction

 

[Jimbo Furgeson]

You have a restriction in your system somewhere blocking the flow. When you are not using water, the pressure equalizes. But when you start using water the restriction will not let the water flow fast enough to maintain pressure.

Clogged filter like VAWellDriller suggested?
I have seen the bladder in a pressure tank block the outlet
Pipe restricted from corrosion?
Did somebody adjust or bump a valve handle?

It’s going to be a process of elimination to find the restriction

Pressure tank is pretty new. Less than a year old. All valves are open. There is very old metal pipe that runs underground to the house. Any suggestions on how to check for, and clear, corroded pipe?

 

[Boycedrilling]

Is there a yard hydrant befor the water line comes into the house? If yes does it have restricted flow? Is there a drain valve at the pressure tank? Check it for flow. Take the areator off your sink faucets and check the flow. As I said, it’s now a process of elimination.

It should have been a matter of a few minutes to empty the pressure tank.

 

[Ryan Greene]

I've been working on a similar issue. Pressure is good at the well, but in the house pressure starts high and gets very low after a few seconds. First thing I did to see if it's the main line was to hook a garden hose to the spigot at the well, then connect the other end to a spigot on the house and open both. Check if you have constant pressure inside the house. For me I have perfect pressure when I do this so I know the restriction is after the well tank and before that house spigot. Then i dug up the main line and cut it, then back flushed the line by leaving the garden hose on both ends and opening them both. This blew out a bunch of crap from the line. I hooked it all back together but still have low pressure, not as low as before but still not where it should be. Check these pictures for a better visual. Sounds like you have metal pipes though so it may be more difficult. Here's a link to my post: https://terrylove.com/forums/index.php?threads/what-came-out-of-my-main-line.78576/

Good luck!