When charging a water pressure tank, how much air should be added?

This article describes how to determine how much air should be added to a building water tank in a building water supply system where a private well is the water source and the well tank is not a bladder type or "captive air" tank.

Q&A on How Much Air is needed in the water pressure tank?

These questions and answers about making the right air pre-charge in a water pressure tank were posted originally at WATER TANK AIR HOW MUCH TO ADD - be sure to review that article.

On 2018-06-28 by (mod) - water tank loses air pressure?

Anon

Losing air pressure ? Really? Or do you mean simply losing water pressure in the system?

That could be a piping leak or a foot valve leak or water running somewhere you haven't noticed, like at a toilet.

Search InspectApedia.com for PUMP RUNS INTERMITTENTLY to see detailed diagnostics.

On 2018-06-28 by Anonymous

set tank at 38 psi pump kicks on at 40 runs until 70 psi then shuts off loosing air pressure till pumo kicks on again at 40 no water runing

Any suggestion

Set tank at 38 psi comes on at 40 ppsi but no pressure in house shuts off at 70 psi but loosing air pressure pump kicks on n off

On 2018-06-04 by (mod) - set the water tank air pressure pre-charge to 2 PSI below the pressure switch cut in

set the water tank air pressure pre-charged to 2 PSI below the pressure switch cut in pressure for example if your pressure switch Cuts in at 30 PSI then set the air recharge to 28 PSI

On 2018-06-04 by Anonymous

@Anonymous,
I need that same answer..Did you get an answer to your question I have the exact same issue and I don’t know how much pressure to put in the tank and it does have a bladder

@Ron Timmerman,

On 2018-05-07 by (mod) - what controls when the pump turns off?

No, it is the pressure control switch setting that determines the cut off pressure and of course the ability of the pump as well as the well to deliver in water and pressure. Take a look at

https://inspectapedia.com/water/Water-Tank-Bladder-Pressure-Adjustment.php

On 2018-05-07 by Anonymous

If you have a brand new pre charged wel tank at 38 psi.....when in operation will the tank pressure rise to 50 psi in order to shut off the pump?

On 2017-11-16 by (mod) - how to add water tank air

Ed

For a bladderless water tank, turn off the pump, drain all pressure from the system, empty the tank - so it will be at atmosphereic pressure (14.6 psi if you're at sea level and reading zero on the pressure gauge)

For a tank using an internal bladder, with pressure drained from the system, the tank's air precharge is set to 2 psi below the CUT IN pressure on the pump pressure control switch.

So if your water pump turns on when the pressure falls to 20 psi, then the tank's air pre charge will be set to 18 psi.

On 2017-11-16 by (mod) - how much air to put in the water tank

Ed

For a bladderless water tank, turn off the pump, drain all pressure from the system, empty the tank - so it will be at atmosphereic pressure (14.6 psi if you're at sea level and reading zero on the pressure gauge)

For a tank using an internal bladder, with pressure drained from the system, the tank's air precharge is set to 2 psi below the CUT IN pressure on the pump pressure control switch.

So if your water pump turns on when the pressure falls to 20 psi, then the tank's air pre charge will be set to 18 psi.

On 2017-11-15 by Ed Wilson

How much air can be put in tank and what's it mean when it says be certain the air pressure in tank is 2 psi below pump start up pressure

On 2017-10-14 by (mod) - put more air in the water tank

With the pressure in your system (and water from the tank) drained and pump off so that zero shows on the pressure gauge,

- for an internal bladder-type water tank, set the air pre-charge pressure to 2 PSI below the CUT-IN pressure that is set on your pump pressure control. So for example if your cut-in pressure is 20 psi set the tank pre-charge to 18 psi.

- for a tank with no internal bladder, drain all water from the tank, so that it is full of air. That's all you should need to do.

On 2017-10-12 by Randy

The air is all gone how much psi should I put to shut off

On 2017-06-30 by Ron Timmerman

I replaced the pressure switch at my tank a few days ago, the water pressure was great, now all of a sudden the water pressure has dropped to very low. the water is still running, but with a very low flow.

What would cause this after it was running so good? If anyone can resolve this problem for me I would deeply appreciate the knowledge and help. Please Reply,

On 2017-05-09 by (mod) - clogged faucet strainer

Kenny

If in the same bathroom you have hot water at a shower but no hot nor cold water at a sink in the same bath, then I suspect the faucet is clogged or the control valves are closed or there is a blocking in piping to the sink. It sounds odd for both hot and cold to a sink to fail at the same time while at an adjacent fixture both hot and cold work.

That's why I think of a clogged faucet strainer.

On 2017-05-09 by kenny

i have hot water to shower and cold also. but nothing in sinks any ideas

On 2017-01-14 by (mod) - find where the pipes are frozen

Rich please stop SHOUTING. Even though you're being driven crazy.

I would follow the pipes from a point where you know fixtures are getting water onwards to where your fixtures are just off or dripping.

On 2017-01-12 by Rich

OH YEA THE TUB AND TOILET RUN OFF THE SAME COLD WATER LINE AND TGE TOILET WORKS FINE AND WASHER GOES OPPOSITE DIRECTION.......DRIVING ME CRAZY

TODAY WAS 42 degrees realfeei 45 still having same problem

On 2017-01-11 05:36:52.941620 by (mod) - frozen water line

I suspect that the water supply to those locations is still frozen somewhere along its route. Leaving the water dripping especially if you can get warm water to drip a bit might speed the thaw out process

On 2017-01-10 by Rich

MY WATER WAS FROZEN AT THE MAIN LINE.....MY KNOW IT ALL BROTHER IN LAW WHILE I WAS THAWIBG OUT THE MAIN RELEASED AIR FRON MY AMTROL VALUE-WELL.......WELL NOW MY PIPES ARE THAWED ALL THE SINKS AND TOILETS WORK FINE THE MAIN BATHROOM IS FINE BUT THE TUB AND SINK IN MY MASTER BATHROOM AND ALSO MY WASHING MACHINE ONLY DRIPS COULD THAT BE BECAUSE OF THE AIR THAT HE RELEASED AND IF SO HOW DO I FIX IT......THANKS IN ADVANCE

On 2017-01-09 by (mod) - sanitize the well after working on it

Thanks for the feedback, Bill.

Good going.

If you have need to sanitize or shock your well please search inspectapedia for

Well shocking procedure

And you will see that the use of liquid household bleach can work just fine in the right concentration. Our article will tell you how much bleach to use based on the static head or volume of water in the well casing. It's not that hard to figure out.

However I never want to use pool chlorine tablets in a well. I'm not sure that we know what the effective disinfectant concentration would be. But worse people who have tried that have had a hell of a hard time getting the chlorine out of the well because you have this solid block that sits at the bottom and deserve very slowly.

On 2017-01-08 by Bill - well casing ok, added rings to protect well wiring

Ok, As far as I can see the casing looks like it's in tack and dry as far down as I can see with my high powered spot light...

This is about day three now and the water has cleared up completely(yay)!! I haven't put anything in my well so far as far as
bleach, was waiting until I heard back about your thoughts on it, so

I did add a couple of the plastic rings to my water line and also installed a Submersible Well Pump Torque Arrestor, which
wasn't present before, so hopefully everything is now going to be ok!

I have extensive knowledge in wiring and plumbing as being a self employed General Contractor for the last 40 years, I just didn't really get into anything involving water wells and such, as noted earlier,

I had replaced our pump over 10 years ago but that only involved cutting and splicing the wires for installation of the new pump itself along with the heat shrink material used, At that time I didn't have any problems with my Water just the dead pump!

So this has been an experience for myself I'll continue to monitor my water and the condition of it now that I have a little more understanding of how things all work, thanks to your help here on your site,,,
Thanks for all your help!
Bill

On 2017-01-06 by (mod) - causes of submersible well pump wiring damage

Bill:

Thank goodness nobody got fried.

Adding:

Thanks for the details: what you report will help other readers.

There is a problem with submersible pumps torquing or twisting the pipes and wiring in the well at the start and less but also at the end of each pump-on cycle.

Components sold to address this problem include torque dampers and spacers to keep pipes and wires from rubbing on the casing - a particular problem in deep wells - and also devices that absorb pump torque at on-off cycles.

You'll want to flush the system until you don't smell bleach. If you have trouble getting rid of the bleach smell you may need to wash down the sides of the well casing, or empty out water pressure tank and water heater tank.

DO NOT use chlorine tablets in a well. See https://inspectapedia.com/water/Well_Chlorination_Shocking_Procedure.php

YOu might see water moving because water is running into the casing from below the water surface. If the casing were damaged you might see also ground water (unsanitary) running down the casing into the well water.

On 2017-01-06 by Bill - found burned up pump wiring

Ok, I pulled the pump and to my surprise I found that the two wire leads to the pump had been burnt completely off about 60 feet deep or so, I didn't notice much tangled or twisted piping or wiring as i was pulling the pump up but I'm almost 100% sure it had been rubbing the well casing and one thing led to another, I repaired the wiring, then we put the 3/4 HP pump in a 55 gal drum with water it started to like bubble at first,

but then all of a sudden it started pumping really well, it was pushing water out of the pitless adapter and the drum water was going down at a really good rate, so I shut it off, cleaned up things best I could,

I then though ok I'm going to do that test I read about here on your site, I placed a piece of copper tubing about 16" over the 100' x 3/8" nylon rope I had and also tied the other end to another piece of 100' para cord I had, lowered the weight down the well until I ran out of the 100' of nylon rope,

and btw about 3/4 the way down I'd say 80' or so I could hear it hitting water, anyways I lowered the rope with the para cord tied on to the end another 50' feet or more and it kept going down more and more,

I now had approx 150' to 175' of rope down the well with the weight on it and it wasn't stopping? ( my well cap is stamped 125' -- 108' of casing, rated @ 10gpm ) so I'm thinking wow, my water amount should be ok.

So I ended up cutting off 3' of water supply piping and lowering the pump back down and see what happens..
I turned on the pump and within 30-40 seconds I had water pumping in the house (YaY!! lol) it was not muddy or really rusty looking

it was more like very cloudy like when you disturb a pond by walking in it and it takes a while for the water to settle down again to become clear... this is what I though was going on anyways,

I noticed the water had been actually clearing up hour after hour so I decided to let it set and not pull any water until the next morning, by then I ran water and it took about 3 mins and it was almost crystal clear,

a day late now it is crystal clear, I'm hoping cutting off 3' and raising the pump height is going to solve my problem (at least until warmer months lol) seems the longer it goes the clearer the water seems to be, we usually don't drink the well water unless we filter it anyways so im happy to have it running again at least for toilets and showers!!

I do have a question or two though to ask,

1. Someone told me to put a couple gallons of bleach down my well then run the pump until I could smell it inside at the faucets, then shut it off and let it stand for a while then later run it off?

Would you suggest this and how many gallons of Clorox should I use, another question related to this one is Since I have a pool I have some 3" chlorine tabs since we don't drink the water anyways would it hurt to drop one or two chlorine tabs down the well and let them dissolve?
I also forgot to tell you, when i used my high powered spot light to look down the well I could actually SEE water way way down, and I thought at one time or so we could actually see it moving??

2. Is this because we just experienced two days of rain and the water table is actually very high right now, or is it possible that the well water level could actually RISE over time?

I'm hoping the water lvl hasn't risen to the actual depth of the casing @ 108' because when I pulled the pump I measured approx. where I thought the water piping shown to be wet from actually being in the water and it was a surprising 30' from that point to the bottom of the pump.

The casing as far down as I could see with my spotlight was Dry, until where I thought I had seen water but I could not tell if the water had actually been UP to where the casing had been or below it, just could not make that out

Thank You for your help in advance I really appreciate it a lot, I was just discouraged when at first I didn't get an answer I just couldn't find anyone or any information online about my problem, and I didn't know where to turn..Thank you agian!
Bill
Ps; I apologize for the length of this post I just tried to give you all the info I could on the problem!

On 2017-01-04 by (mod) - causes of brown well water

Sorry you're upset, Bill. Sometimes, with millions of readers, the question rate gets ahead of us. Apologies.

Brown water: I'd have the water tested so we know what we're looking at: a contaminant, mud or silt, rust debris. For example, low water in the well can cause the problem you describe but so can the problem occur from a damaged well casing (inspect the casing with a camera) or even from a well piping leak that squirts and stirs up silt in the well.

So let's do some diagnosis (inspecting) before going to anything costly. Sure you could try just pulling up the pump 2 feet as that's cheap. But surely something has changed.

On 2017-01-03 by Bill

I'm now wondering if my pump is setting too low in the well? since the brown like water, mud is showing up again all of a sudden?

now I have no water and pump wont run hopefully it has a protection switch on it but if not guess I'LL BE PULLING THE PUMP my follow up question how do I know the depth to lower my PUMP into the well so as to NOT have it setting on the bottom and collecting mud and debri from the bottom of the well? someone told me to pull it inspect the pump if it runs and is not burnt up cut off about 2 feet of water line and reinstall the pump is this a reasonable amount of piping to cut off?
Thanks
Bill

On 2016-12-10 by Bill

Replaced my well pump about 10-12 years ago, 125' well, once in a while I would get some really bad rust/mud color looking water when I turned on the faucet, along with a black

Gritty type substance in the sinks and tubs, sometimes it would get so bad I had to clean out all the faucet inserts, and tub faucet inserts, replace the whole mech. inside the toilet because it became clogged and wouldn't fill the toilet, this happened about every 9-11 months?

now its happening quite often like every couple months, If I catch it and let things set idle for a couple hours we have no problem if someone forgets and draws water to do laundry or dishes, they pull all the love thru the system and we have problems, what is happening? do I need a new well ? my current well to be dug deeper?

or another new pump? dont know where to start looking if so whats a ball park figure if I need my well to be dug deeper?

I just got everything cleaned up from our last episode/ not looking forward to another one! Please, any help in what to do or look for will be greatly appreciated !!
Bill

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On 2016-09-29 by (mod) -

Thanks SmithB. We work hard to provide free, authoritative information without bias so we're really happy when a reader finds InspectApedia.com useful. We also welcome questions, criticism, content suggestions, corrections. Working together makes us smarter.

On 2016-09-29 by Smithb147

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On 2016-07-03 by (mod) - pump won't run after power failure

Shelley

Typically the cause of the condition you describe is a leaky check valve or foot valve. When the power is on the valve leaks slowly until the pump comes on and re-pressurizes the system. When there is no electrical power the leak continues until the pump has lost prime.

DO NOT keep running the pump as running "dry" can damage it. Your plumber or well repair company will find and replace the leaky valve(s) after confirming that that's the problem.

On 2016-07-03 by Shelley

So my power was off for a few days. I now have no water. Pump won't kick in. Pressure tank has no pressure. What do I do

On 2016-06-23 by (mod) - working on pipes when there is no shutoff and no water tank drain

The tank will have piping connected to it. That piping either goes to a drain or you can install one by turning off the pump, draining pressure from the system, then cutting the pipe.

If necessary there are freeze fittings or other devices that let us work on water pipes without draining the system. Let me know if you need help finding one of these.

On 2016-06-23 by walt

How can I let water out of a water tank that has no drain?

On 2016-05-15 by (mod) - pressure falls after pump stops

Tom, check for a bad check valve, leaky foot valve, or a leak in well piping.

On 2016-05-15 by tom

my pump kicks off at 60, but the pressure drops and does not hold pressure

On 2016-05-04 by (mod) - excessive water pressure not caused by tank air charge

Wrong water pressure tank pre-charged pressure is not a cause of intermittent or repeated water pump on off cycling. Rather I suspect a leaky or stuck foot valve. Another possibility would be a leak in the well typing.

I suspect a leaky or stuck foot valve. Another possibility would be a leak in the well typing.


Turn off water to the house. If the pump continues to cycle on and off, you know the problem is in the well piping or foot valve.

On 2016-05-04 by Anonymous

Few weeks ago the hose on my refrig that runs water to my ice cub maker popped off. After getting a new clamp and putting it on it came off again. Needless to say I realized I had a water pressure issue. After looking closer at my water system I noticed that my water gague always read 35psi even with water running.

After replacing the gague I noticed my water pressure spike to above 100psi where I replaced the pressure switch and the smaller connecting rod which was completely filled with sediment. This very same sediment months prior cases my impeller on my water softner meter to halt and not properly regulate my regeneration system.

With all this in mind I recently put in a hole house water filter before my water tank in order to a dress the sediment issues I have.

Since putting in the filter and completely flushing my system of what sediment I could my water pump seems to be intermentently cycling on and off every 15 mins.

There is no leaks in my house and the wx-203 tank is fine from what I can diagnose. How likely is it that the issue is the foot valve? Any other possible causes, maybe under/over charge tank? Thought?!?! Thanks in advance for your time, Matt

On 2016-04-20 by (mod) - pump runs but no water comes out

Check for

- lost prime

- damaged pump impeller

- disconnected or leaky well piping

Search InspectApedia for NO WATER PRESSURE to read details

On 2016-04-20 by Randolph

Hey my pump is tuning but there is no water coming out

On 2015-12-24 22:25:49.195799 by (mod) - well pump was coming on every 7 or so seconds,

Thanks for the feedback DIY'er. WE work hard to make our information accurate and useful so are really happy when we hear that it's worked for you.

Daniel

On 2015-12-24 by Do it your selfer

Hey, my well pump was coming on every 7 or so seconds, and it was shaking the well T when it did come on. I read your website and diagnosed it and added air and now I've got it so it goes 31 seconds. Thanks for the info it was very helpful, the guide type format really helps for diagnosis.

Question:

(Jan 2, 2015) Anonymous said:
how much air should be in a water pressure tank

Reply:

Anon,

The answer is in pressure rather than volume, in part because there is no single right voiume answer given that tank sizes vary. Set the air pre-charge pressure to 2 psi below the pressure control switch cut-in pressure - that adjustment is for a tank that is empty of water.

Question:

(Mar 5, 2015) vicfordlop@gmail.com said:
My pressure switch is set at 60 to 40. As soon as I turn on my water, the pressure drops to about 30 psi. I have a 315 gallon tank.Please help. My water pressure is low at my faucets and outside faucets. I can only turn on one at a time in the house.

(Mar 5, 2015) Vic ford said:
Do I need to drain my 315 gallon tank to add extra air. Also, does a 315 gallon tank actually hold that many gallons. What does it hold.

Reply:

Vic

If the pressure drops very rapidly as soon as you turn on the water that suggests that the pressure tank is waterlogged.

...

Continue reading at WATER TANK AIR HOW MUCH TO ADD or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• WATER TANK AIR, HOW TO ADD
• AIR DISCHARGE at FAUCETS, FIXTURES
• SNIFTER & DRAIN BACK VALVES
• WATER TANK AIR VOLUME CONTROLS
• WATER TANK AIR ADD AT AIR VALVE
• WATER TANK AIR ADD BY DRAINING
• WATER TANK AIR HOW MUCH TO ADD
• WATER TANK AIR HOW OFTEN TO ADD
• WATER TANK AIR INLET VALVE

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WATER TANK AIR CHARGE QUANTITY FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS & SPRINGS

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