Water tank FAQs #2:
These questions discuss the purpose of water storage or water pressure tanks on private well systems. How to diagnose & correct short cycling "on-off" of the building water pump.
This article series explains the different types of water tanks such as tanks using an internal bladder or diaphragm, bladderless steel, fiberglass, or plastic water tanks, and water tank pressure and air controls and valves.
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These questions & answers about water tanks were posted originally at WATER TANK: USES, TROUBLESHOOTING - the home page for this subject.
Does a home water pump need a water tank. can i run the water pump without a water tank. some days no water will reach 2nd floor. and some days even on the 1st floor water is weak. currently running no pump. - Ian 09/2011
Why do we need a water pressure tank?
Ian, with a water pressure tank and the air "spring" that it contains, the pump will short cycle on and off rapidly in many circumstances, delivering water in spurts and short cycling the pump on and off rapidly in any case at which water is being run more slowly than the pump output capacity.
That's because water is practically non-compressible. The air charge in the water pressure tank acts as a giant "spring" to give a continuous flow of water and to work with the pressure control switch to turn the pump on and off at a range of pressures typically about 20 psi apart, such as on/off at 20/40 psi or at 30/50 psi.
An exception, where no water pressure tank is needed, is when a water pump is being used in an open system, such as pumping water out of a creek or pond into an open stock watering tank or planting field. In that case, because the pump is picking up water from its source and pushing it to a destination without a restriction in the system, the pump moves water continuously as long as it is on and does not stop until it is turned off.
Supposedly the overflow valve in the water tank failed causing an amount of water to overflow from the tank. onto the roof area and down into the elevator which caused water damage on the top of the elevator cabs ...there is now only one elevator in the building and the other one has to be run manually.
The risers were drained in he basement to remove the sediment from the lines, The water was rusty for quite some time as well as off completely.
Can you offer me your expertise on this alleged unforeseen emergency The building is almost 50 yrs old Was built in 1966. thanks
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem whether it's with the failed valve in your water storage tank or in explaining how water moved from there into the elevator shafts. That said, it sounds as if you are describing a triple fault:
How is it the case that water from a spillage on the rooftop got into the elevator shaft and why wouldn't rainfall or snow-melt have done the same?
I'm not sure what other research or support you are requesting, but if you have a specific question let me know and I'll do my best.
Do the Bladderless Steel Water Pressure Tanks help reduse the smelly water problem? - Joe Y
Joe y: I'm not sure how the type of water pressure tank would reduce a smelly water problem. In most communities you can have your water tested for free by water treatment companies and sometimes by other agencies.
You need to identify the source of odor and based on that information an expert can recommend a water treatment system that can reduce or remove the unwanted odors. See ODORS in WATER for details on diagnosing and fixing water smells or odors.
My well guy told me that there are "weep holes" in the well pipe that is deep in the ground. It's expensive to pull a well pump and seal those weep holes so I really have to stay with a bladderless system.
The home improvement places do not carry bladderless tanks anymore but they are still available. - Anonymous
Anonymous: frankly I'm unclear why the system you describe would make one iota of difference between choosing a bladder-type or bladderless water pressure tank. In either case the tanks have the same working effect on the plumbing system.
If your well piping is leaking and you are losing tank pressure back into the well after the pump shuts off, the proper repair is to replace the leaky well line (saving burn out of the pump), though you could try installing a check valve above ground on the line that returns to the well. Review this with an experienced plumber so you get it right.
However, it is certianly true that on some submersible pump installations that used a bladderless water pressure tank, a snifter valve system was used to maintain the air volume in the water pressure tank.
The snifter valve system can include an air inlet valve above ground near the water pressure tank and an air inlet and water drain outlet port that is installed on a special fitting on the water riser pipe inside the well. Where a snifter valve system is installed it needs to be removed when changing to an internal bladder water pressure tank.
We discuss snifter valves on wells and water pressure tanks in detail at WATER TANK AIR VOLUME CONTROLS.
I have a 120 gal galvanized water tank that's beginning to corrode. This deep well services my house and lawn sprinklers and it's worked fine for decades. I read about the AVC which I have and it was replaced recently.
I was wondering how it is adjusted with the adjustment screw? It gets "stuck" sometimes and I have to mess with the screw to stop air bubbling into the house. However, then I get water coming out of the screw adjustment which I had left slightly cracked open because I didn't realize there was a float inside the unit. I was also wondering if I could switch to a bladder type tank or if it is better to stay with what I have. I've read a lot here and thank you for the useful information.
So are there any advantages to going to a bladder tank? One thing I am not sure of is how air is pumped into the tank I have. Obviously, I would have to stop the air addition if I go to a bladder system. My system doesn't have one of those disk shaped thingamajiggers that I read about in here that adds air. Any help would be appreciated. - Steve J.
I made an error in the statement below, the galvanized take is 82 gallons in volume, not 120.
After more research, sounds like the non bladder system I have is best because the addition of air and occasional automatic air purging removes some well water gasses resulting in a fresher water supply. People kept referring to the non bladder system as "old" technology but it appears to also be better technology.
I have a U.S. Gauge Type 310WJ installed but that appears to just let air out of the system, not add it. Am I missing something about how that gauge works? The description written in here says that it adds air with each pump cycle but looking at the gauge, I don't see how that's scientifically possible.
I would still like to know how the air is pumped into my system. Perhaps I need to contact US Gauge. Thanks again for all the details written here - it was a big help.
Steve J:
A bladderless water pressure tank might be referred to as "old technology" because of the history of difficulty keeping an air charge in the tank. Air is absorbed into water in the tank over time and so has to be made up.
Systems that automatically add air typically do so by allowing a valve to open to let air into the system when the in-tank pressure drops, closing again as in-tank pressure rises. Indeed it's scientifically possible; some such devices tend to clog or fail over time however.
The types of air volume controls used on bladderless water pressure tanks are explained beginning at WATER TANK AIR VOLUME CONTROLS. You'll also want to review snifter valve systems used for air volume controls as we explain in detail in that article.
A few years back I had our old water tank replaced with a HT20 bladder tank, every since then we loose water pressure as the water runs (taking a long shower, watering the garden ( we cant run a sprinkler in the garden as it looses the pressure to keep it flowing)) I have been told it could be many things, I adjusted the pressure in the tank from 20 to about 28-30 and we ran out of water pressure faster, so I adjusted it back to 20 and the water pressure last longer, now I was told that maybe I need a bigger tank. I was told that I should have about a 30-35 gallon instead of the 20gal. Should I invest a couple hundred in a new tank or could it be something else? - Phil
Phill:
Changing the water pressure tank size, from smaller to a larger unit, does not change water pressure delivered in the home. Pressure is determined by the capability of the water pump and the settings of the water pressure control switch.
If you are not running out of water but water pressure falls off too much during the pump cycle, the gap between pump cut in and cut-out may be too large. You can change this by adjusting the pump pressure control switch. Details are at WATER PRESSURE CONTROL SWITCH ADJUSTMENTS.
But we have heard from quite a few readers who complained of water pressure variation problems after changing out their water pressure tank. Often the problem is traced not to the new tank but to debris and crud stirred up in the water piping system during the plumbing operation. If the water supply is contaminated with silt, mud, debris, or if water piping includes rusty iron, debris can easily clog the water pressure control switch sensor opening on the bottom of the switch, or it may clog the small diameter pipe nipple used to mount the pressure control switch to the water system.
Replacing the clogged pipe nipple and pressure control switch can fix that problem. But if the water supply has silt or mud in it you'll also need to install a water filtration system or the clog problem is likley to recur again soon.
WATER PUMP DIAGNOSTIC TABLE lists other causes of water pressure and flow problems along with recommended steps to confirm the diagnosis and cure the problem.
I tried what you recommended and adjusted the gap on the pressure control switch and didn’t effect anything at all, so per the recommendation from my local hardware store I replaced my gauge and the pressure control switch to a 30/50 one. I have more pressure at the beginning but the water flow diminishes after running it for awhile (it is better though and the pressure is better as well). Do you think I need a bigger tank or could it be something more serious like a well problem or well tip? If it could be the tank size could I add a 20-30 gallon tank (in line) before the other 20 gallon tank so I would have more water storage or doesn't it work that way?
Thank You
Phill, it is normal for water pressure in the building to vary through the pump cycle, from the low (cut in) to the high (cut out). A larger water pressure tank won't change those pressure limits but it would give you a longer draw-down time between pump on cycles and in that sense water pressure would drop more slowly.
But if your water flow rate exceeds the rate that the pump is capable of delivering, the pump will run continuously while you're running water. If in that condition the water pressure and flow are inadequate, you'd need a more powerful water pump to improve the pressure.
If the poor pressure were due to clogged piping the symptoms would be similar but I think the pump might have a better chance of "catching up" when water is being run.
My tank pressure is dropping although i have shut off the main valve from the pressure tank to the house and have a check valve from the well to the pump to prevent pressure drop. Still the pressure gauge is still slowly loosing pressure. Has anyone experienced this? help advise please. thanks. - Rey.
Rey: if the water pressure tank pressure falls after you have closed valves into the building, one of these may be the problem:
See WATER PUMP DIAGNOSTIC TABLE and WATER PRESSURE PUMP REPAIR GUIDE
Having a problem where water stops flowing completely out of the faucet at about 40 PSI, then the pump kicks in at about 35 PSI. There's a several second time frame where no water comes out (very inconvenient in the shower) while waiting for the pump to cut in.
I can remove this delay by turning the cut-in nut on my pressure switch (9013FSG 2) clock-wise, but the point at which there's no water output drop-off before the pump starting results in about a 65 PSI cut-off point.
I can't see this high a pressure being good for my pump or the water fittings throughout the house. Does anyone have any ideas about how to get the pump to turn on while water is still flowing? I don't really understand the water tank, so I'm wondering if I need more pressure in it to keep the water flowing until the pump cuts in. Help! - Greg F
Greg I wonder if your pressure gauge is clogged with debris and not giving an accurate picture of system pressures, or if the pressure control switch is itself debris clogged. Certainly your description sounds like a sticky pressure control switch.
See WATER PUMP PRESSURE CONTROL REPAIR for details on diagnosing and fixing pressure control switch problems.
Twice now we have experienced air in our water fixtures. I have drained the pressure tank and everything has worked fine for approximately 2 weeks, and then the problem has started again. Any advise as to what could be causing this. Our pressure tank is probably about 30 years old and it is a private well. - Mike 1/7/12
Mike at AIR DISCHARGE at FAUCETS, FIXTURES (article link in Related Topics section near page top) we give diagnostic procedures for air in water fixtures.
I have a single outdoor water line that i'm using for an outdoor shower... i've put a pressurized bladder 85gallon tank for naturally hot water (sun blasts this thing in summer) and water storage... to store a reasonable amount of water, what would you recommend i set the psi on the bladder to? do i set that when empty or when there is water... i think incoming pressure is about 30psi - Dave 1/20/12
Dave, please see the instructions at WATER TANK BLADDER PRESSURE ADJUSTMENT
I found that after being in the home for a year, that my water pressure was low. I replaced the pressure switch and the pressure gauge. Watching the gauge it shows that the pressure goes to approx 30psi and no higher. The contacts on the pressure switch show closed. If I turn the power switch off, the pressure guage goes to zero. Do I have a pressure tank issue, foot valve issue or some other issue? - Bill B
Bill, you may have a well with very modest flow rate, or a pump that is damaged and can't reach cutoff pressure, or a leak in the well piping that has the same effect. When water pressure drops to zero on the gauge, if it really is zero no water would be coming out of your water faucets. If this is the case then the pressure control switch is not turning on the pump when it should, OR the pump is not working OR the well is out of water.
Can a water reservoir tank be placed under a mobile home or does it have to be next to the well pump? - Jay 9/13/2012
Jay
A water reservoir tank can be located almost anywhere, though there are considerations of installation cost as well as access for inspection and maintenance as well as freeze protection depending on your climate. Generally the tank and pressure control need to be close together for best operation.
Why would there be two 300 gal plastic water storage tanks in my basement other then storage? Could it be a fix to something problematic? - JD 9/30/12
JD,
When we see very large on-site water storage at a private house we figure that the ability of the well to deliver water, its flow rate or recovery rate, is very very minimal - someone installed large water tanks intending that the pump and well fill those tanks very slowly, over time, including when no one is using any water (at night when you're asleep for example) so that when you need water there is some stored in the tanks.
What this means to you is that your well is not very effective and you may need to address that problem soon.
have water at well not in house - Anon 10/6/12
Anon
Your question doesn't give anything to go on, but I imagine you are saying the well is not dry and you've no water in the house. I mean, I'm not sure how you know that there's water in the well.
See WATER PRESSURE PROBLEM DIAGNOSIS TABLE (article link in Related Topics section near page top) for a tabular guide to diagnosing your lost water pressure problem.
the tank fills with soemthing like 3 gallons - i think that's not normal, how do I fix it? - Anon 10/17/12
Anon, take a look at the labels on the pressure tank, or the instruction and installation guide to see what the rated tank capacity is in gallons of water; if you don't have that information tell us the brand and tank model (send along photos if you like) and we'll look it up for you. If the tank is one that uses an internal bladder and you cannot get water to enter the tank the bladder may have collapsed and stuck to itself. If the tank is not a model that permits internal bladder replacement, the tank is shot - needs replacement.
If your tank does not use an internal bladder then the problem is elsewhere, with the well, valves, piping, controls - I'd need to know more.
we just purchased a pre-charged pressure tank. it didn't come with a air control valve kit. do we need to purhcase the kit? the pump is working without it - Cheryl 10/17/12
Cheryl
No you should not have to buy a kit - I'm unclear what kit there is. I'm guessing that you are referring to some water pressure tanks taht may exclude an air pressure adjustment valve are not be adjustable, come with a factory pre-set charge pressure, and work as is. However IF your tank manufacturer provided a tapping on the pressure tank intended to accept an air valve and if the instructions recommend installing one, offering the valve as a separate part, you might need to purchase the valve and adjust air pressure IF the tank is not working acceptably as is. If you see 30 seconds or longer of draw down before the pump turns on you are probably ok.
I was fixing some issues with the insulation in my pump house and the power to the pump was cut off inadvertently. The whole system lost pressure and the pressure tank emptied completely. Am I supposed to bleed the system to get back to normal pressures? - Tim 12/15/12
Tim, it sounds as if you might have a bad check valve or foot valve that let the system drain back onto the well.
now all tanks from all condominiums are filled each day at around 6:30pm by a giant tank (probably underground).
The problem is we have to switch off the motor (have to be there at this time or switch the valve if we plan to not be there) and turn an valve, then water flow in the water tank until the float (bulbe and not electronics) stop the water.
It is the general and basic system used in South America and I heard in few other countries too, as you can see very primitive.
Now I will like to know if someone or a company have the brightest idea to build a electronic system to make it all completely automatic
I means, timer, open-close valve and switch on/off the motor.
Because of course the motor switch have to be on once the tank is full, the motor not turn but in standby until someone take water from home, and stay open until no one need anymore water, then the motor power off, (not the switch)
Can you tell me something about it. This is a blue plastic tak about 7' long, plastic. - anonymous 12/27/2012
Dear anonymous:
We'd like to help but I think I may need a few added details. To start, we have a very similar system here at our location in Mexico. A tanque atop the building is filled at various times by means of water pressure from a city system. The tank fill-up procedure is stopped by a mechanical valve much like a toilet float. I think that's what you have as well. With that system the water storage tank will fill automatically with no trouble - we leave the manual fill-valve from the city open at all times; It will feed water into the top of the water tank until the tank is filled, then the valve at that location stops the fill process.
If you need to manually open and close your tank fill-supply valve manually it may be because your fill pipe enters your tank bottom - in that arrangement, if you didn't close the fill valve water would drain backwards out of your water tank back into the supply system - a bad design for several reasons including the risk of back-contamination of the main supply by a contaminant found in an individual home's water tank.
The pump system you describe is a common installation here in Mexico as well, though not on most homes - most buildings supply water into the building by gravity - elevating the water tank if needed to improve water flow rate and pressure. But for homes in which occupants want or need more water pressure, a booster pump is installed.
If a water pressure booster pump is installed by itself, the pump indeed turns on as soon as you start running water and turns off when you stop running water. This is a bit hard on the pump and shortens its life. A better installation is to include a water pressure tank in the plumbing system - usually next to your water supply tank and water pump; the pressure tank allows the pump to turn on and off under control of a water pressure switch (typically on at 20 psi and off at 40 psi);
With that design and paying attention to how water is delivered (to the top of your water tank and controlled by a mechanical valve) you should not need a more costly electronic sensor and valve control system.
Send me some photos and sketches of your water supply system and we can perhaps comment further and more accurately.
(Feb 6, 2013) jt said:
i recently replaced my pressure switch as the old one was sticking. Now I have good pressure on the cold side, but poor pressure on the hot side. both were good and equal before the pressure switch change. I drained the hot water tank but that has not helped. any thoughts?
(Feb 27, 2013) Jas said:
We have a deep well, 400 feet, and a holding tank. We recently had company over we used more water than normal over a few days and the water stopped flowing out of the faucets. We had the pump checked and it was in good running condition. Then after 3 days of no water the water started flowing again with full pressure like nothing was ever wrong. Do you have an explanation for this?
(Mar 10, 2013) mark said:
we live in a place with cold winters. our pressure tank is outside. i am building a new shed for it with thick walls so i can add lots of insulation. are there advantages of placing the shed on a concrete slab? would be good to drop the tank and plumbing a foot or so into the ground (the supply pipes are already 30 inches deep)?
JT: look for debris clogging in the hot water tank outlet, piping, or control valves
Jas: your well may have a limited flow rate - and took a long time to recover.
Mark,
You don't say what your winter climate temperatures are so I'm just guessing but ...
A foot or so lowering the tank won't do a thing for you - you'd need to get everything down into a well pit that was itself below the frost line.
A slab in the tank shed is a good idea - especially if you insulate beneath the slab and then provide some safe heat for the space.
(Apr 3, 2013) Marife said:
Hello! I have a water Refill station (RO) and deep well source of water, can you tell me what kind of pressure tank i need to use for this. Thanks
Sorry Marife I don't see enough data to have an opinion. Perhaps the thing to do is call the equipment manufacturer to see if they have a special requirement. If not, I can't imagine why you'd need some variation other than a normal home water pressure tank.
(Jan 24, 2014) Rhett said:
I'm considering installing two 119 gallon pressure tanks in series for extra capacity. Is there any disadvantages in doing this?
Rhett,
Presuming you're addressing a problem of poor well flow or recovery rate and are discussing adding a large onsite storage capacity, no, not that I see, other than space, costs, controls.
(Jan 24, 2014) Rhett said:
The well is 320' feet with a static of 105'. The well produces 200 gallons per minute, so there are no flow or recovery issues. We will be doing a lot of irrigating during the summer months, plus power washing cars. I figured the extra storage capacity would reduce the amount of times the pump kicks on and off. Besides the electric pump at 200 feet, we are also installing a backup solar pump at 150 feet. The solar pump will be mainly a backup system, but pumps about .75 gallons a minute. I will have a 1700 gallon storage cistern for the solar, but thought the 119 would add additional storage. I know this sounds overkill, but I would rather be overkill than put strain on my electric or solar pumps.
I understand better from the added details, thanks.
200 GPM is a stunning water flow rate from a well, more than ten times what I read is provided by residential water wells.
I'm not sure that adding a large *water storage* system would do a thing for the pump on-off cycling rate. The pump and water pressure tank don't know whether the water is coming from a well or from a storage tank.
But adding one or two large-volume *water pressure* tanks would indeed lengthen the draw-down cycle and thus decrease the well pump cycling rate.
We may just be trying to clarify terminology here.
To reduce the pump on-off cycling rate what you want is a very large water pressure tank with a large air charge, to give a much longer draw-down cycle. Some installations combine these features in one very large water tank by placing the pressure control switch right on the large storage tank itself.
Our article link titled WATER TANK: USES, TROUBLESHOOTING - (search InspectApedia) discusses how pressure tanks work , while a separate article: WATER STORAGE TANKS, LARGE shows how a large water storage tank can also be used to give a long draw-down cycle.
Keep us posted, and if you can, send along photos of your system using the CONTACT link on our pages.
(Feb 12, 2014) Andrea Acker said:
I have a small pipe feeding me water from the municipal village water supply. My pressure drops off when the village uses too much water, so that it will reach my first floor but not the second floor. Can I use a pressurized tank without a pump, so I can just store extra water inside my house under the village pressure? Will this then give me the same pressure as the water was at when it filled the tank until the tank is drawn all the way down? My goal is to have water available at the seconsd story at all times (even when the village water pressure will not push it up there) ISs this or a tank with a float valve feedign gravity feed water into the second story a better and cheaper solution?
Andrea, You could install a pressure tank with no pump, figuring that it gives you a brief pressure boost for a small water quantity but without a pump and pump control you'll probably get just a few minutes of boosted water pressure (say 1-3 minutes depending on the starting pressure when the muni system is at preak pressure and the flow rate at your plumbing fixture).
In sum, you want a pump and pressure control switch that will draw water from the municipal system and push delivery pressure up to an acceptable level during periods of poor municipal pressure.
In communities where municipal water pressure is not just sometimes slow, but sometimes off alltogether, we feed municipal water to a rooftop tank, using a pump if necessary, then store water in that tank, often 100g or more, so that water can be delivered down to the building at good pressure at all times. Indeed, those tanks often operate by a float valve that fills the tank from slow-muni pressure when tank level drops; and those tanks may feed into the building plumbing fixtures by gravity alone, or by a pressure booster pump (and separate pressure tank). If you read our InspectApedia article about "Rooftop water tanks" you can see some of these.
I should add that you don't have to use a rooftop water tank to boost pressure; other buildings use a simple pressure tank and pump as I described in the first part of my initial comments. That system can be located in a basement or on another building floor as is convenient.
...
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