need help choosing a pressure tank

I’m wondering how big or small a pressure tank I need.  I have heard that too small a tank requires the pump to run too much, and wears out the pump.

Are there disadvantages to a larger pressure tank? …. Other than higher cost of purchase and installation?

Also I read a thing about various kinds of pressure tanks:  air over water, diaphragm, bladder, are there others?

What’s the longevity of the different types of pressure tanks?  

I have a new place, quite rural, I can find someone to install it, but I need to know enough to tell who to hire and it may be me who goes to the store and brings it home….  I need to know how to talk intelligently about my options once I get to the store… or know what to order…

I live alone, but sometimes I have 6-8 guests.  We need to be able to flush one toilet while someone is in the shower and not freeze or scald them.

Currently there is no pressure tank.  I think it failed and the prior owner took it out and bypassed it.

Thanks for all your help.

Big vote for a big tank. Or if your space is tight, a few smaller ones daisy chained together. The pump starts/stops less and runs longer when needed, which is more energy efficient and reduces wear and tear. You also have a larger emergency reserve if the electricity grid goes down for a while.

The "hot/cold shower shock" issue is more of a plumbing design issue. It does however encourage thoughtful actions and good communication within a household. I learned this firsthand.

Air over water is the old style tank. I had one of these in my previous homestead, an old farmhouse. It's a simple tank with a cushion of air at the top, which acts as a spring. They work all right, but as the tank empties and refills, the turbulence slowly drains away the air cushion. No problem, it's just maintenance -- drain the entire tank and use an air compressor to fill it to ~30psi once a year. Voila, you're back in business.

All the tanks for sale these days have some sort of an internal bladder setup (picture a heavy duty balloon) so the air cushion "spring" doesn't dissipate. I can't make specific recommendations but I can say it seems exceedingly rare for anyone to replace a pressure tank unless they are upgrading their well system.

I do wish my current tank had a direct tap (in addition to a whole house shutoff valve). The ability to drain off sediment or to attach an honest to god garden hose for cleanup jobs in winter would be highly useful.

Hi Thekla,
First, a question, is your pump a variable frequency drive, or pressure switch operated? You can make a good guess by knowing whether the pump is submerged (VFD) or somewhere where you can see the pipes going to and from it (and if it has a little box on the side with a tube going to it, that's the pressure switch). Both types use a pressure tank, but with the VFD pumps, the tank is small, 1-2gal, to smooth output as the pump electronics adjust. If the pump is switch controlled, it's either on or off, and the largest pressure tank will allow the longest runtime, which is generally better for the pump.
Good luck,
Mark

Mark Miner wrote:First, a question, is your pump a variable frequency drive, or pressure switch operated?

Mark, that's interesting. I didn't realize that VFD's had filtered down to the consumer level. I still associate them with the 5000 HP behemoths my industrial clients use. But at either end of the scale, the energy efficiency gains can be stunning.

Do you know the flow rate of your well pump and the desired minimum run time?

Get a tank that fits you budget.  There is no such thing as a a pressure tank that's too large.

Thank you, Douglas, Mark and Anne…
I don’t have a well, or a pump.  I have low flow domestic water.  There’s a 1000 gallon cistern that has been bypassed, and there’s evidence of a long term leak and catastrophic failure probably of a former pressure tank.  The cistern loses about 50 gallons per day into the surrounding soil.

For now I am on a meter  as part of a system where almost everyone is on a dole. (Takes a month to deliver  the allotted 10,000 gallons).

I am trying to educate myself about the component parts of a system that would have increased pressure.  Currently I have low enough pressure that the toilet tank doesn’t refill if anything else is on, and I can’t run a simple frog-eye sprinkler.  

I have timed how long it takes to fill a 5 gallon bucket but will have to do it again because I forgot, but wouldn’t gallons per minute  substitute for well output?  

I can go back on the dole, but would need to provide my own pressure.  Would a modern submersible pump in the cistern provide me with that, or would I need a pressurized tank in the house?

The water was out for 3 days last winter due to ice somewhere…  The electricity has not gone off in the 10 months since I arrived.  

Thekla McDaniels wrote:I don’t have a well, or a pump.  I have low flow domestic water.  There’s a 1000 gallon cistern that has been bypassed, and there’s evidence of a long term leak and catastrophic failure probably of a former pressure tank.  The cistern loses about 50 gallons per day into the surrounding soil.

For now I am on a meter  as part of a system where almost everyone is on a dole. (Takes a month to deliver  the allotted 10,000 gallons).

I am trying to educate myself about the component parts of a system that would have increased pressure.  Currently I have low enough pressure that the toilet tank doesn’t refill if anything else is on, and I can’t run a simple frog-eye sprinkler.  

Personally I would try to work with the metered water system. I'm trying to understand if the issue is low pressure or low flow. Do you get a momentary burst of decent pressure when you first turn on a tap, and then it tapers off quickly? That suggests a low flow issue. If so, a large pressure tank with a check valve (one way flow valve) may help a lot without needing a pump.

Also, what setup do your neighbours have? Local knowledge can be useful. Or can you call up a local well/plumbing company and chat them up about options people are using? The outfit that supplies your water should be able to tell you the typical system pressure you can expect from their distribution system.

Hey thekla. I would need to know more details on what you have going on. But what it sounds like you will need a pump and a pressure tank.

The pump moves the water up, and the pressure tank is like a cushion of water so the pump isn't always running. There's a few ways to approach this.

Run a shallow well jet pump followed by a pressure tank, welltrol wx-202 or wx-203 is a good size for your needs.( 20 or 30 gallon).

You can tie both the water lines ( dole and cistern) and have valves to be able to control/isolate each depending on what's available to use. If you do that you're going to need a pump for each location. Unless you have a way to pull water from both systems using one pump.

You then plumb in the pressure tank after the pump. Do some research on some diagrams, they show you how to plumb the fittings and what fittings you will. If you need help just send me a message I'll be glad to. I use to do this for work.

The submersible pump for cistern will work, you will need to put the pressure tank after the pump somewhere in line between the cistern and your water valve and lines. The pressure tank gives you the cushion of water so you don't burn your pump. What the guys said above is good advice for the types and you will need to maintain the air inside. You can get a bicycle pump and a small pressure gauge. Research how to service a pressure tank not too hard.

You could also put in a booster pump on your domestic dole water but that's a lot more expensive. That don't use a pressure tank(you can if you want) the pump runs every time you use water and adjusts the pressure based on your usage etc.

With your given situation, I'd suggest you try to rig up a rainwater system and have it feed your cistern. Maybe looks to get the cistern patched, I know that ain't cheap baby lol. Or you could run the rainwater into a few ibc totes and pump that through few filters into your home. You will have to figure something out for freezing temperatures.

Hope that helps and best of luck. If need help on details send me a message I'll be glad to talk you through it

Most of my neighbors have dole and cisterns of varying ages, though I bet I could find out some good information from some of them.  They may have had to replace pumps and such, and I would get to know more of them!  Thanks for the reminder!  

One of the problems I have experienced with neighbors is that I never get the same story twice, even from the same person! … and so I come to Permies😊

There’s no initial burst of pressure.  This morning it takes 1 minute to receive a gallon of water.

Most of the water company’s customers are on dole system.  Only a very few are metered.  I think the pressure at point of delivery on the metered system is variable.  Really, it’s miraculous that the water system even exists.

Thanks for the support!

Hi Thekla,
I do recall your cistern post previously, but I did not realize you didn't have a pump already. I seem to recall you are in Portugal, yes? At least, I will assume a non-US supply chain.

Since you don't trust the meter line pressure, but do get adequate water volume, two avenues occur to me if you really want more pressure: put a new tank higher uphill (with direct feed to the house) to increase house pressure, filled either by your slow line or a pump from your system, essentially making your own water tower; or, put a pump system ahead of your house, fed from your cistern, either a sumbersible VFD or a switched pump and pressure tank. Grundfos is Danish, and has both types of pumps (*based on my US experience), and is generally a good brand. If your use is minor and domestic, Grundfos even makes some smaller VFD non submersibles, meant to do exactly that job, pulling from a cistern and boosting pressure to a house. If you pump agriculturally at all, you might wear out that class of pump quickly, though. Look up Scala2 pumps if this seems appealing.
Good luck!
Mark

Hi Mark

I am in western Colorado rather than Portugal.

I am getting a clearer idea how to proceed from the conversations here on Permies

I do want to use some water for agriculture, but don’t plan to exceed 10,000 gallons a month.  Should I mention that when I talk about this situation?

If money were not a consideration I would seal the cistern, have dole fill the cistern, pump out of the cistern for house, garden, stock water and put all the “extra” water in a pond.  I would build a frost proof shed above the cistern, with the means to heat it (rmh).  That is years out.  Maybe my interim plan is a large pressure tank in the house.

I probably don’t utilize 80,000 gallons of my yearly 120,000 gallon allotment!

I usae about a 25L pressure tank ina house with 3 people all the time.

Hey Thekla,

I think we're getting a better picture of your situation.

First things first -- I think you need a water storage reservoir as the foundation of your system. If your metered water system can deliver 1 gal/min, that is potentially 60 gal/hr x 24h = 1440 gal/day. That's a nice amount of water, but you would need to store it somehow to have a decent reservoir to supply your house plumbing. An outdoor seasonal tank would be brilliant. There are also indoor cisterns tanks (poly tanks) that can fit through existing doorways for frost-safe winter use. Honestly, without this initial, unpressured reservoir of water, a pump and pressure tank will not solve the problem.

Once you have this water reservoir for a pump to draw upon, a cheap 120VAC jet pump matched with a pressure tank will supply your house piping very nicely.

(As an aside - Personally I would have the metered water trickling into some sort of catchment all the time day and night. Indoor cistern, outdoor cistern, rain barrels, fish pond, anything. There's nothing more important than a water reserve on site.)

Apologies, Thekla, I had you mixed up with someone else!

That said, Franklin is my go to US brand of pump, I think the rest of my comments are reasonable. I like the 3/4 hp Franklins, and used them for lots of tree watering in AZ, with a 44gal pressure tank and pressure switch.
Best,
Mark

This is wonderful, thank you.

I wonder if I can manage water storage under the house for the pressurized system to draw from.  And I wonder if there’s a pressurized tank that would also fit in a crawlspace.  The only ones I have ever seen are vertical.  

Or, if I need easy access, maybe an added insulated shed adjacent to the house, or a dedicated utility room within the existing heated space might be best of all.

I think my two outdoor frostfree hydrants are plumbed into the house water.  

It would be great to water new trees and vegetables, herbs etc.  I haven’t devised a good way to do the outdoor watering with the low pressure.  It takes so long, and I need to move the hose frequently.  And I forget.

In the wintertime, there are usually a few days out of the month when the hoses aren’t frozen.  I would like to run “my” excess water into the pond (which I have yet to build).  In a winter without snow cover, the ground dries out.  Trees need winter water to get established.  It’s just one puzzle after another.

So, I am thinking I need the larger (60-80 gallons) tank for the pressure tank if I am going to try to run hoses off it, is that correct?

Sorry to be so disorganized in my presentation.  I am thinking it through as I write.  Currently I am having the house leveled, and a foundation put under the house so it will stay level.  Then begins the process of renewing and repairing the house.  When I started all this I thought I did not want the water system inside because I thought the pump would be noisy… but now when I think about building a heated structure, it seems like a lot of extra work (and or expense).  A good sign I need a break from planning and building!

Does a pump for a pressure tank make a lot of noise?

A jet pump certainly makes some noise, though you can make an insulated housing to reduce that. I had one at my previous property. But a bit of noise is not always a bad thing. A few times I woke up to use the loo and wondered "why is that damn pump running?" Answer - I forgot to shut off an outside hose before I went to bed. Oops.

I’ve had an oops or two like that🤣

For a while, I officed in the shipping container that was also the power station and water hub of our property. 1hp jet pumps will make a Zoom meeting awkward if you are 6ft away. However, Douglas is spot on, hearing it kick on at night after dinner washup and kids abed was usually a reminder to go check something. Also, the noise difference between 3/4hp and 1hp is large in the Franklin VersaJets, and that is why I suggest (and installed for clients) the 3/4hp for modest domestic use!

I have laid pressure tanks on the side with no problems.
Will the tank be subject to freezing?
If so will that be an issue?