Well Water Tanks

I’d like to know, what is the failure rate of captive air tanks compared to the older traditional tanks?

I was at Easton for a few days in an attempt to reconfigure my water system to a more permanent setup. Part of  the work was to move an 80 Gallon pressurized tank from the shed near the cabin to the new Well house about 400 feet away. The well house is powered by a 6/1 generator, and it’s floor is about 4 feet into the ground, the hope is the well insulated and earth protected building will not freeze in the winter, I guess we’ll know soon enough.


First thing I did was make sure the bottom valve was all the way open, and empty of water, then I went to load it into a light trailer for the trip behind the ATV to the new Well house. Yikes, it’s heavy! first thing I checked was for air pressure on the air side of the bladder, seemed to have plenty, but I shook the tank, and it was at least half way full of water!

I tipped it over on its side and looked at the bottom, there was a bolt circle on the bottom maybe eight inches in diameter, I loosened the bolts, and after slacking off about three, there was a blast of putrid, foul smelling water that started spraying everywhere, I backed up, and let it spray, it was muddy looking, almost jet black, lots of solids, and finally it seemed to ‘heal’ itself. I decided to slacken off the bolts more, and it blew again, and sprayed more of the same foul smelling stuff. After backing off the bolts about four different times, pressure fell to zero and I was able to take off the bottom flange and inspect the bladder. As you might imagine, all looked just fine, I was able to stick the hose inside the tank and flush out a lot of ugly stuff. I did a pretty good job of flushing it all out, and then added some bleach water, at this point, I was experimenting, and attempting to get the tank operational for the rest of my stay as I processed what was going on, and what I’d do for a permanent remedy. I put the tank back together and charged the bladder to 50 PSI, if there’s a leak, it’s small indeed, I guess I need measure it next visit to know more.

As I thought about this, and my fondness for pressurized tanks, my mind darted back to an incident at Cowiche, another off grid piece of property we own in the Cowiche Mountains, There was a time when I returned to the cabin and opened the faucet in the utility sink near the shower, out came a green soup that actually fizzed like an effervescent soda drink! I ran some out into a plastic wash tub and it reminded me of some science project. The smell was memorable indeed. Thankfully, we only use this water for showering, but we do wash dishes with it after running it through a propane heater. Since I had a gallon of bleach, I poured about 50 times more than necessary in with the spring water in the 55 gallon barrels and recharged the tank AFTER purging it. What is note worthy is it happened again about two months latter.

Now what I’m about to say is all theory, I’m no water expert, I never attended a single class on water wells, and I certainly don’t have a certificate from the health department certifying me as anything. At most, I’m only a consumer of water, and I mostly like mine as fresh as possible. But unlike normal folks, I have the DIYer bug, you got it too or you wouldn’t have read this far.

I said I like pressurized tanks, I guess I better tell you why. A tank with a bladder inside can be charged with air and acts as an accumulator, (an active element) in your water supply, when properly installed and sized, it can significantly decrease the number of starts and stops of your pump, and in single phase pumps (most of what we home owners have) the number of starts is directly related to how long the pump usually lives. Running a pump is not as hard on the pump as starting it.

What you could enjoy researching is how tanks worked prior to the bladder tank, to give you the short of it, there was a method to inject some air every time the pump cycled, this is necessary because air will dissolve into water, and sooner or later the air space would be gone!  The air is what drives the water out of the tank when you go for a glass of water, also note that water doesn’t compress worth a darn, so bad things would happen without the air space. The pump doesn’t need to run with modest draw downs once the pumps shuts off. The bladder tank WILL allow you to use twice the volume of water BEFORE the pump starts as the earlier water tanks of equal size, and some suggest an even bigger advantage. In theory this could double the life of your expensive electric pump. There’s another notable benefit, when the power goes out, you have more water in storage that will flow from the faucet before you need power again. If you can keep from flushing the toilet on yellow AND you use the water for the most important requirements like drinking and cooking, you might weather your outage in reasonable comfort.

The CONS ?

Here’s close to reality on how this tank works, and close to what the directions say.. there’s an air filler on the tank same as your car tire, use an air pump to pre charge, use a tire pressure gauge to measure the pressure. There’s usually some literature with your tank and to what he pre charge should be and how it relates to the cut in and cut out settings of your tank. Here’s a page from a leading tank manufacturer.  I don’t know if their tanks are good, better, or best.

If you study the pre charge, and you study the range of pressures the water side can operate between, what happens if there’s a small hole in the bladder? The closer we maintain the two pressures (bladder and water pressure) the less likely it will be that any real volume of water and/or water+?pathogens? flow. But lets look at the pressure right before the pump turns on, it could set at this pressures for hours or days depending on use, the bladder side may be at a higher pressure and if there was a hole in the bladder, the ‘soup’ could flow into the drinking water and contaminate it. When the pump does come on, it will likely run the water side to a greater pressure, and the water from that side could flow back to the air side and provide a continuous water supply to the ‘soup and pathogens’ manufacturing line.

I have not researched the offerings in pressurized tanks, but having some telltale when there is water detected on the air bladder side might be a great selling point. If it were a feature, I’d likely buy it!

Now if we look at Cowiche, and the ‘worst case’, I likely ran that tank down to about zero pressure. If there was 20 gallons of soupy water and bugs on the bladder side, it might charge the water side with that ugly stuff until the pressure equalizes. When I walk into the cabin, there it is again! that ugly smelly water EVEN though I shocked the tank with chlorine. Is the bladder leaking at Cowiche too?

So here I am wondering what to do for Easton, do I risk buying another expensive bladder tank?

Now we add one more piece of information, I call a friend who just had a well put it, his water man said he doesn’t install the pressurized tanks anymore because of the call back rate, he says he seldom gets called back on a job where he installed the older tanks with the air injectors. Is this a customer education issue, or a high failure rate of the captive air tanks? There are tanks with a five year warranty.

Here is an email from Phil P., a first class DIyer


Having been on wells for over 32 years I can give an honest opinion on water storage tanks. I have never had a bladder tank nor will I ever have one.

My friends and neighbors all have them and I can’t remember even one of them that has not had a problem with a bladder tank. Some last only a couple of years before they rupture, (stinky water and waterlogged tank, constant pump cycling).

I have a steel glass lined tank with an air valve (40 gal.) Works great although the air valve needs to be replaced every 10 – 12 years depending on your water quality. I have hard water and they eventually lime up and the valve doesn’t seat properly.

Also with my system are two bleeder valves in the water line ( submersible pump ) where the horizontal pressure water line turns down into the well casing. They are about 30″ apart and they bleed off any pressure after the pump shuts off ( they are in the vertical line in the casing )

Their purpose is to bleed off pressure so the pump does not start under pressure next time it runs, check valve located just above them to retain tank pressure. They also admit air into the line as the water drains out between the two bleeder valves.

New air valves are about $18 at the local farm stores.

Another home we used to own had a well with a shallow well jet pump, the literature for the pump and tank was in the basement when we bought the home – dated 1947, wards jet pump and tank. We sold that home when we built our new one in 1994 and that pump and galvanized tank were still in service although I did do some repairs.

It did not have a air valve but it did have a schrader valve on the tank to charge it with air or you could just drain the tank and “starterup” again – did the same thing as pumping in air only easier.
Needed draining or air pumped into tank about every 2-3 months.
That’s my opinion on water storage tanks – no bladder tanks period.


Some thoughts, and I hope more feedback can be used to determine how prevalent failures are in these thanks.

Captive Air Tanks offer some real advantages when you have a single phase pump, far less pump cycling, and the fact that hard water is stored in a bladder and does not touch metal is very appealing to me. It may be a wise move to research the better bladder design, and to install a “quick check” system for detecting faults with the bladder. Understanding the bladder and how long you can go before detecting a problem gives me some thoughts. Improper Air Charge and other faults could cost you your pump or other troubles.

Installing a cheap indicator lamp off the pump controller so you can see when the pump is running sounds like a necessity, This might even be something you can monitor from a typical ‘point of use’, a small red indicator light on any time to pump is running. When it starts ‘short cycling’ you’d have a way of knowing.

I think we consider making use of that lifting eye in the top of the tank, once a year or more often, we turn off the pump, and completely empty the tank, we design a place to attach a simple balance scale between the ceiling and the tank, we could even make a crude balance and leave it in place. With flexible black plastic or similar to the tank, we could know the weight empty, and we would quickly discover when we had a few gallons (or more) of water on the air side of the bladder, this could give us plenty of time to replace the tank BEFORE we compromise our pump or other problems develop. Knowing the weight of the tank new is key.  I think problems at summer homes or places where water systems are unused for months at a time could really benefit from a drain down of the water tank, and a quick measure of the weight of the tank. I can see a tank set up with a permanent balance scale, when the tank is drained, you see the tank 1/2 inch off the floor.

well water tanks

Above, a simple balance and weight installed permanently to monitor for faults in bladder tanks this could be made out of a piece of pipe, a few holes drilled, and some chain.

More research, I looked at a captive air tank being tossed out at Easton, there was no way to replace the bladder, so you just toss the tank. My tank is a Flotec I believe, and the liner IS replaceable, what we are all certain of is that the liner will be expensive! regardless of what they cost to make, the general rule is they price the liner just low enough for you to compare the cost of a whole new tank against the cost of a new liner, I will call for a price during the week, no service on Saturdays.

One thing we know, if that’s bear steel on the air side. we need clean it and seal it up before we install a new liner, it’s possible that linseed oil might work, possibly better is a zinc rich paint with high solids.

For those who want to start a submersible pump off a generator, what considerations should we give to our design WHEN we put it in?  If we have a fairly deep well, and a low static level, is there any consideration to allow this tall column of water to ‘bleed off’, and what effect will it have on the current to start the pump, and the duration of that high current as the pump starts?

Suggested reading from friends of Utterpower:

This article above points out that the captive air tank stores the water in the bladder where it never touches metal, this sounds like a big advantage when you have hard water.

Information on iron and manganese in drinking water.

Here is on on bacterial sludge.

One on Iron Sulfer Bacteria.

This one has a lot of good condensed advice!

And finally, one about Interesting Pumps.

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2 Responses to Well Water Tanks

  1. athmy dutta says:

    its idea that air tank stores the water in the bladders and it never touch the metal parts, this result more advantage while using hard water

  2. Carol Knott says:

    i have just purchased an eagle water filtration system,
    which includes a 20 litre water holding tank with neoprene bladder

    how free of zeno-estragens is neoprene
    could one find a glass lined one instead>why did the water stagnate
    wastes for drinking or washing only sounds like the system was open to bacterial contamination

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