Water tank air inlet valve (C) Daniel Friedman Q&A on How to Add Air to a Water Pressure Tank by the Air Valve

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

FAQs on how to add air to the water pressure tank by pumping at the air inlet valve:

Questions & answers on how to use the air valve on a water pressure tank to add air to the tank or to pre-charge the pressure tank with the proper amount of air. The air charge in the pressure tank is critical to avoid water pump short cycling on and off.

This article series describes how to add air to a building water pressure tank, and how to detect and correct air and water leaks in a building water supply system where a private well is the water source.

Green links show where you are. © Copyright 2017, All Rights Reserved.

FAQs on Adding Air to the Water Tank using the Air Valve

Snifter valve on a submersible pump well system (C) D Friedman

These questions & answers about how to use the air valve to add air or pressure to a water pressure tank were posted originally at WATER TANK AIR ADD AT AIR VALVE

On 2017-07-20 by (mod) how much bar to pre-charge the pressure tank


Pre-charge the empty water tank to 2 psi or 0.14 Bar below the pressure control switch CUT-IN pressure.

On 2017-07-20 by San

200Ltr pressure vessel how much bar want to fill

On 2017-07-20 by (mod) how much bar to pre-charge the pressure tank

The air valve used to add air into a pressure tank is described in WATER TANK AIR ADD AT AIR VALVE.

On 2017-07-04 by Anonymous

I don't know which is the correct valve to put air back into my tank

On 2017-05-17 by (mod) why the pressure in the tank goes from 28 to 40 psi after a cycle 40/50


I'm not sure where the 40/50 cycle term is coming from. Typically a factory-set pressure control switch is set to CUT IN at 20 psi and CUT OUT at 40 psi, OR to CUT IN at 30 psi and CUT OUT at 50 psi.

You could be seeing different pressures if someone changed the settings or adjustments in your pressure control switch. If you use the InspectApedia search box just above to find PRESSURE CONTROL SWITCH ADJUSTMENT you will find details of that procedure.

On 2017-05-17 by Ricardo

My question is why the pressure in the tank goes from 28 to 40 psi after a cycle 40/50 thanks.

On 2017-04-13 by (mod) do i have to empty the tank (water) and then pre-charge the air bladder or is the tank gauge faulty ?


The jet pump itself ought not run low on air - it doesn't want to see any air, but you are perhaps telling me about the water pressure tank connected to your jet pump.

The pressure you'll read at the tank depends on when in the pumping cycle you measure it.
If you drain ALL pressure from the system (pump OFF) and then set the air pre-charge to 2 psi below the pump CUT-IN - in your case 38 psi.

On 2017-04-13 by john popp

I have a jet pump normal range 40-60 psi. It ran low on air and I added air via schrader valve to 38 psi using a digital tire gauge to measure pressure at the schrader.

The tank gauge shows only 27 psi - do i have to empty the tank (water) and then pre-charge the air bladder or is the tank gauge faulty ?

On 2017-02-05 by dennis belk

lost prime after changing suction hose/pressure switch/gauge on deep well. when trying to prime thru gauge ,it only took approximately 4oz. turn on and gauge went to 20#. and slowly dropped to zero within 10 seconds. help

On2016-11-27 by Anonymous

Great information. Thank you

On2016-11-11 by (mod) re: sometimes lose water pressure, not sure exactly what to re-set the switch to


Filters can of course clog and cut water flow rate - or "pressure" at the fixtures. Iron can also clog pipes.

If the water flow rate is notably better with the filters out or offline that'd be diagnostic.

The fact that your pump turns on immediately suggests that your pressure tank is waterlogged. Search for WELL PUMP SHORT CYCLING to read how to diagnose and fix that.

Short cycling doesn't immediately explain weak water pressure but can, over time, damage the pump.

On2016-11-10 01:41:23.460233 by Margaret

my water pressure on a well system with a pressure tank has been decreasing over time. The water pressure is sometimes pretty good, but then other times, hardly any water will come out. The well pump itself is 2 years old.

I don't know the size of the tank, it is a WellXTrol, probably several years old, not sure. The pump kicks on almost immediately after turning on a faucet and continues to run for quite a while after faucet is shut off. The well has a LOT of iron in it. There are currently 3 filters but they are all after the pressure tank.

The filters don't seem to do much to remove the iron. I have to change the medium at least monthly. All of the pipe is poly but some of the fittings are galvanized.

Plastic ones sometimes would freeze and/or crack. The pressure gauge was new 2 years ago when the new pump was installed. It was set at 40 psi but has continually dropped and now is at about 12 psi. When I tried to add air to the tank using a air compressor, water comes out the valve and doesn't seem to let any air in.

The water seems to be under fairly high pressure. I have read about re-setting the pressure switch, but since I can't change the pressure on the pressure gauge by adding air, not sure exactly what to re-set the switch to. Any suggestions for what to check or what to do? Thanks.

On2016-10-31 by (mod) I think my tank is water logged


A water-logged tank will cause pump short cycling - rapid on-off switching; that might overheat the pump and cause it to turn off.

The kick-in or "cut-in" pressure on a residential system is usually 20 psi or 30 psi and the cut-off is usually 40 or 50 psi.

On2016-10-31 13:28:52.012231 by lois

I have a shut off switch on my well pump for to safe guard my pump in case the water level goes low. I know I have water in my well but am having difficulty in keeping my pump running.

I think my tank is water logged. to restart my pump lately, I have had to open water line and hold switch until water started to come out line. If I then, closed tap, my pressure gauge would move and finally, I would get water. Now, that is not working.

My pressure gauge sits at 40 or a little below at all times but seems to need to hold switch a little longer to get pressure a little higher before pump will run on its own. Could my tank be water-logged? What should my kick-in pressure be?

On2016-09-28 by (mod) I would rather not rely on electricity or an expensive manual deep well hand pump.


You might search for RAM JET WATER PUMP to see an alternative.

On2016-09-26 by JNoon

How do i get water pressure without using electricity, gravity, or manual pump?

I'd like to fill a water tank by lifting and pouring from buckets, close the fill pipe and then pressurize the tank to supply up to 30 gallons to one faucet in a small off grid cabin.

I would rather not rely on electricity or an expensive manual deep well hand pump. Another thought is to bucket fill a barrel inside the cabin and pump from that using a shallow well pitcher pump. Ideas?

On2016-09-02 by (mod) is it normal for water to come out of the Schrader valve?

No, not for a tank that uses an internal bladder - that is if the valve you're checking is the one near the top of the tank.

More likely the tank bladder has burst or the tank is waterlogged.

On2016-09-02 by Tubero

I am trying to check the bladder's pressure, is it normal for water to come out of the Schrader valve?

On2016-08-08 by (mod) loosening both adjustment screws and starting all over

Russ you're asking about adjustment screws in an article about air pressure adjustment valves for a pressure tank.

I think you want to search InspectApedia for


and for


as those two articles give complete detail about the adjustment screws for a water pump pressure control switch.

If you're asking about something else just let us know.

On2016-08-07 by Russ

I asked earlier about loosening both adjustment screws and starting allover is that ok or not?answer would be appreciated thanx

On2016-06-01 by (mod) Have air coming out of faucet


Please search InspectApedia for AIR DISCHARGE AT FAUCETS to read details and suggestions

On2016-06-01 by Roger

Have air coming out of fauset when you turn it on but clears up after you run it for a little bit

On2016-05-03 by James

My shutoff pressure switch will not switch off

On2016-01-05 by (mod) pump cannot reach shutoff pressure

If the pump cannot reach shutoff pressure there are several causes involving switch, piping leaks, or low well flow.

Please search InspectApedia for WELL PUMP WON'T STOP RUNNING to see diagnostic and repair details.

On2016-01-05 by TJC Scotia

I have a well with a water treatment system. I shut off main water from well fixed a leaky tub faucet , turned water back on. water pressure only reaches 35 lbs. Needs to hit 60 lbs to shut off clorinator. It will continually hold at 35-38 for days, and come back to 35-38 after using water

It never goes above that to shut off pressure switch to turn off clorinator. I did try adding air manually to 60 lbs to bladder tank, clorinator shut off and held 60lbs for days until I took a shower. Dropped back to 35-38lbs Thats where it stays as we speak. ANY IDEAS????

On2015-11-16 by (mod)

Thank you so much for the feedback. We are so happy that this worked for you. We also welcome questions critique and comments from oureaders.

On2015-11-15 by Dan Anderson


Just wanted to say thanks for the info. My homes pump was short cycling because my air pressure had run down.I followed the instructions and now my pump has returned to normal

Thanks again

On2015-10-08 by Gary

pipe broke at water tank do I need to add air to the bladder water tank when fixed?

On2015-09-24 by (mod) Increasing water tank air pressure will not improve water flow rate from your well.

Increasing water tank air pressure will not improve water flow rate from your well. The well's own flow rate and the pressure capacity of the pump set that.

On2015-09-24 by Anonymous

I am getting a low flow of water from my well I put air in of 2 bar but im still getting a low flow of water should I increace the air pressure to 3 bar

Question: Well pump is cycling intermittently at 45 second intervals.

(Dec 27, 2014) Dick said:
Well pump is cycling intermittently at 45 second intervals. It takes 45 seconds from cut in to cut out and the same from cut out back to cut in. I have isolated the house by closing the main water valve at the tank. I recently replaced this valve because the old gate valve failed last week while I was replacing my water heater.

I replaced it with a quarter turn ball valve. Isolating the house has no effect on the condition, confirming that the problem exists between the house and the well somewhere...Water LEVEL in the water tank appears to be correct. Water PRESSURE in the water tank also appears to be correct.

I opened the valve between the tank and the main shutoff and got a good strong, clear stream of water. I have rapped and tapped at all the intersections of piping around the tank and pump switch. All to no avail. Any ideas? Thanks.


Dick in the Water Pump Repair Guide articles in More Reading at the end of this article, see the diagnostic article titled


Question: is the air inlet valve repairable or do I have to replace the whole tank?

(Jan 22, 2015) Tina Clifford said:
air inlet valve in leaking. Can we put a new valve on or do we have to buy a whole new tank?


(Jan 23, 2015) (mod) said:

Tina if the leak is at the valve stem or core, that part can be replaced using an ordinary automotive tire valve tool to remove the old valve core and to install a new one.

However when buying the new valve core you want to buy one that is designed to operate in the same pressure range as that selected by the manufacturer of your water pressure tank - which may be (and often is) quite a bit lower than that found in an automotive supply store.

Check with the manufacturer. This may not matter fxor some installations but for water system air valves used in SOME designs that require automatic air venting

See SNIFTER & DRAIN BACK VALVES and see also the article starting at the top of WATER TANK AIR ADD AT AIR VALVE. A low-release-pressure valve core is needed.


Continue reading at WATER TANK AIR ADD AT AIR VALVE - use the valve to add air to the pressure tank, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER TANK AIR INLET VALVE - explanation of what water tank air valves are, what they look like, how to find them


Or see AIR VOLUME CONTROLS, WATER TANK used on bladderless water pressure tanks



Or see WATER TANK AIR VALVE REPAIRS To fix a bad water tank air valve see details at

Suggested citation for this web page

WATER TANK AIR ADD at VALVE FAQs at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman