I have a rural house that is fed by a well system. Pump, tank, and then through the house. The problem is that the tank never fills up. It pumps water, bypasses the tank, and proceeds into the house (where it provides just enough water to perform very basic tasks) and, of course, the pump never shuts off because it never builds pressure.
I’ve checked the air pressure in the bladder of the tank and it reads normal. Any ideas of what would cause the pump to bypass the tank?
is there a value that is closed that shuts the pressure tank off from the rest of the system.
What do you mean by “I’ve checked the air pressure in the bladder of the tank and it reads normal.” What is normal? It should read some lower value, like 30 psi maybe initially, then as the tank fills up it should increase to something like 50 psi (normal values for your system may be a bit different from this). Is it staying at the lower value? This might indicate that water can’t get into the pressure tank, which is probably what johnpost is suspecting. If there is no shutoff valve then the line into the pressure tank could be clogged.
If there isn’t anything blocking water from getting into the pressure tank then I’d wonder if the pump is going south and can’t overcome the pressure required to fill the tank.
Is there maybe a leak in the feed coming up from the well?
If the pump is never shutting off then your system is not developing pressure.
In a properly running system if you shut off the tank the system will still develope pressure and shut the pump off. When you open a faucet and let a little water flow the pressure will drop and the pump restart. The function of the tank is to stabilize the system and absorb pressure fulxuations.
Your tank is being “by passed” because you are not developing pressure. If you can put a pressure gage at the pump well head. Shut you pump off, close every valve in the system. Now start the pump while watching the pressure. If the pump will not develop pressure then you have one of two problems. Either you pump is not pumping or you have a major leak.
Reasons why a pump not pumping. Plugged suction or discharge strainer. Pump air bound needing priming. Not enough water in well. Problems with motor. Bad impeller. Pump bad.
This is the most likely answer. Other failures could cause similar results.
Your tank has a set pressure bellow the pressure the pump is set to turn on at. If the pump can not produce enough pressure to exceed that, the tank would remain mostly air.
There are many reasons a pump might not be developing pressure. I’d recommend getting someone qualified to trouble shoot it.
Yes. When I shut it, the tank still doesn’t fill.
It is supposed to be at 28psi to start. It remains at 28psi. The pump is about two days older than God. The inlet to the tank is cold as if there is water passing there. Perhaps the pump is failing…
I’ve known a person who’s water tank was completely full of sand sucked up by the pump.
Maybe the limit switch that turns the pump on. If your tank never gets above 28psi, I would say the high limit is too low. It sounds like maybe the high and low limit are set the same. You can adjust the switch with a screwdriver, but be careful, pletty of hot wires in there. And we are talking 220v.
The air pressure tank has a bladder in it to separate the air from the water. These bladders develop leaks over time. I just replaced my air pressure tank this spring, at about 20 years of age. The symptoms I had sound exactly like yours. For a couple of years I went down every few months and re-charged the air tank with a bicycle pump. This would reduce the cycle time of the well pump and increase my water pressure. But the pressure would start to drop after a few weeks, and the pump would need to run more often to keep up.
It cost me about $100 to replace the air tank and all has been well since. I managed to do it myself. It wasn’t too difficult.
Isolate the pump and tank completely from the supply to the house. Hopefully there is a valve there.
You want only the Pump and the Tank. Start the pump, see if it builds pressure. If it does, then you have a leak somewhere in your house/hose piping (which is very common, especially if the old black supply line was used). If you do not build pressure to just the tank, and it is a simple pump (no down-hole pump), then the pump is probably just worn out. That does happen over time. It is possible to change the impeller, but probably not worth it.
When my foot valve rusted out, the pump motor continuously cycled.
Update: Problem solved.
I pulled the pipe up from the well. At the end of the pipe, there was a metal mesh screen which I supposed acts as a filter. It was filled with greenish glop.
Once I cleaned that, the system acts normally.
I would guess that greenish glop should not be in my well. I brought home a sample and tested it. While it tests a little on the hard side, everything else seems normal.
Any ideas what this green stuff is? I don’t notice it in the house water.
That would be the foot valve. The glop was keeping it open.
I win! 
No idea what the glop was, though.
The foot valve is a one way valve that lets water be sucked up by the pump, but keeps it from running back out.
Sounds like bacteria or algae. You may want to chlorinate your well.
http://blogs.howstuffworks.com/2009/08/31/how-do-you-chlorinate-a-well/