Water Well and Pump Repair/Storage tank water/air level


QUESTION: Hey Robert:

My question:
I have a submersible well with a 120 gal tank above ground. How can I tell if the tank water-to air ratio is correct?
There is a gauge on the side of the tank with a screw for adjusting the air I believe ,but not sure.

When I feel the tank, it is like cold about half way up, if that tells you anything.

Thanks for the help


ANSWER: Dennis,

Galvanized tanks with the Air Release valve like you described work very well.  The device with the screw has a float inside the tank that opens and closes a schrader valve to let out air when it gets down to roughly the half way mark.  You probably will see a brass check valve in between the tank and the pump.  That valve probably has a schrader valve (like on your cars tire) that allows the pipe from the valve to the droppipe drain every cycle so that the pump can shove more air into the tank each pump cycle.  It's a great system. If your in the north, the cold water will give away the water's level quite nicely after the pump has gone through a recent cycle.

The adjustment screw is to keep the air release from letting out air when the pressure in the tank drops below a certain pressure. It's to keep a little reserve in case of a power outage.  It works well, but the screw also helps the Air Release valve plug up sooner.

You can learn a lot about pumps etc. on my site:  http://www.pumpsandtanks.com

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick return Robert.
So from what I grasp, the gauge and valve I see on the side of my tank has a float attached inside the tank. You mentioned a Schrader valve also, but I do not have one on my system. Is there supposed to be one? Should I get one and can I install it myself. (Do not want to pull the drop pipe) Also, why the gauge with this valve.?
Another item, can I install a constant pressure valve (60psi) on this system?

Hope I am not a nuisance.

Thanks Dennis

The gauge is just there to monitor your pressure.  It may or may not work.  Most of us sell cheap gauges because customers don't want to pay for a good expensive one.  They are mostly there for us to set things up.  After that they're not necessary.

If you don't see the check valve and schrader, don't worry, there is a device somewhere that is making air to that tank.  That is if it's half full of air.  It should take some time for the pump to come on once the tank is full and someone opens a valve somewhere.  The drawdown would be around 14 gallons or better.  Yes you could install a constant pressure valve.  It should go between the pump and tank.  

Water Well and Pump Repair

All Answers

Answers by Expert:

Ask Experts


Robert Tabor


I can answer any question related to Water Wells, Water Pumps and Water Filtration.


From age 13 to age 66

High School

©2017 About.com. All rights reserved.