What size well pump do I need?


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Old 11-23-14, 01:50 PM
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What size well pump do I need?

Hello everyone, I'm building a new home on top of a hill on an old farm. There is an existing well at the bottom of the hill 100' down and 800' away that is no longer in use.

I need to know what size well pump I would need to pump the water up to the house.

The well is by the old farm house and I plan on pulling power from the farm house.

The well is 40' deep. But from the top of the well, I still have to pump the water up the hill to the new site, so that's another 100' of elevation. The new house has 4.5baths. And the supply line is 1.5"s.

I haven't measure the diameter of the well, but it's either 6-8"s. 40ft deep.

Any thoughts on what size well pump to get?
And does the pressure tank belong at the house or at the bottom of the hill in the well house?

Thank you for reading!
 
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Old 11-23-14, 04:44 PM
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I have to ask if building a new, rather large home why you want to rely on an old, shallow well?
 
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Old 11-23-14, 05:15 PM
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I was told that the water was very good and wouldn't run dry.
 
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Old 11-24-14, 04:41 AM
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Will you be able to get power to your pump so far away?

First figure out how much water you want at the house. Then add in the Resistance for your length of pipe and the additional pressure required because of the elevation difference (there are online calculators & charts). Then look at the output charts of pumps and pick one that will provide the flow and pressure you want.
 
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Old 11-24-14, 05:38 AM
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Yes

Thanks for your reply.
 
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Old 11-24-14, 07:55 PM
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Yea that is far far away 800 ft of pipe 800 ft of wire, can it be done is the question, get a quote to drill a new well closer by while your at it and compare.
 
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Old 11-25-14, 07:45 AM
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The wire gauge will have to be really big to run 240V 800 feet. Most people in similar situation get the power company to run a line out there from a nearby transformer (if none, then a transformer will be needed) and a separate meter.

There are voltage drop calculators online like this one. Voltage Drop Calculator

It says you will probably need to 6 AWG wire to run that far if the pump is 15 amps. No more than 5% drop will be acceptable.
 
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Old 11-25-14, 09:07 AM
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I don't even want to know what that much #6 wire is going to cost. Then it will have to be run somehow. That's an awfully long trench to dig.
 
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Old 11-25-14, 07:58 PM
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Power source

I have power at the old farm house by the well.

So, I would like to have the pressure tank and switch there and not run #4AL at 80cents per foot the whole 800ft.
 
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Old 11-26-14, 06:34 AM
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Let's leave the distance out for now.

First, you have to get the water tested for drinking water. If the well is polluted (and many are these days) you can only use it for irrigation which is a different type of well than one used for drinking water.

If you have power and a place to put your pressure tank, then we start at the beginning. How many gallons per minute will be needed? That's going depend on how much the pump can put out.

Some people have wells that can only produce 1/2 gallon per minute. Others can produce 20 gallons per minute or more. What should be done is a test of how much it can produce. You can rent a gas powered pump for not much money and then use large containers, like 5 or ten gallon cans or buckets.

Then you have to figure out how much water you need. What if all the toilets were flushed while someone was in the shower and the dishes were being washed in the sink? Knowing the toilet tank volume, how long does it take now to fill? Your shower head is rated in GPM, what is that? If you turn on the hose outside, how many gallons that does that take in a minute.

This will give you an idea of how many gallons you will need to keep in reserve and for how long. Then when you know that, you can compare what you need to how much you can get. Pressure tanks vary little, but in general, they hold about 40% of their rating, so a 50 gallon pressure tank holds ~20 gallons of water and the rest is air.

You may wonder why all this is necessary, but you are gong to need more pressure from the pump and the pressure tank than usual to make this work. More pressure equals more air and less water.

You could also use two pumps, one to draw the water and the other at the house to boost the pressure.
 
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Old 11-26-14, 06:22 PM
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Pressure tank sizing?

I may end up with two pumps.

So with more pressure, I need more air space. And being that I want to locate the pressure tank at the bottom of the hill, it will need to see pressure 80-100psi to give me 40-60psi at the house.

I'm going with a 1.5hp pump, now I just need to size the pressure tank.
 
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Old 11-27-14, 05:03 AM
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Keep in mind that hp does not determine the water volume or pressure. Two different pumps with the same hp can have very different pumping characteristics. Many people just fall into the trap that thinking more hp is better when all you're doing is running a big motor with the incorrect pump for the job.

Why is it so important to put the pressure tank at the well? Not only will the tank be operating at much higher pressure you also have to protect it from freezing. It also places your surge reserve to handle sudden peaks in demand very far away from where the water is needed. Water has a lot of mass so when you open a couple faucets are opened at the same time the water in your 800 feet of pipe has to get moving before anything happens at the pressure tank.

You may also have issue with water hammer. When a faucet is running in the house all the water in that 800 feet of pipe is moving. Flip the faucet knob closed and suddenly all that water has nowhere to go and slams to a hault. It can be very hard on pipes and fittings. It can cause a loud clunk or bang sound after you turn the faucet off and eventually it can cause leaks as pipes and fittings get hammered to death.
 
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Old 11-27-14, 07:57 AM
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"I'm going with a 1.5hp pump"

How do you know your well can support that much pump? I think you are guessing. I think that it is pretty good guess, and I would guess the same, but it is still a guess.

100 feet is the equivalent of a 10 story building. Maybe you can google on that and see what turns up.

--added a little later--
Maybe you can rent a pump, hook it up to the 800' of pipe you will need to buy anyway and see what happens. At least it will give you an idea of what to do next. I've never run a pipe that far for an on demand system, only for irrigation from a lake to an open sprinkler head (mostly a big gun), so I don't know about water hammer.
 
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Old 11-28-14, 06:31 AM
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Wait. I know what you need. You need a pump curve for the pump you are thinking about buying.

Here is how to read one:
http://www.austincc.edu/hart/lab-mat...ic_systems.pdf

Once you read this, you will know why you need one.

Getting one could be a problem. If you walk up to a clerk in a big box store and ask the clerk for one they will look at you funny, but if you go to a real pump store (we have them here on the side of the road in the rural areas) and ask, they will have them on file and will be much more knowledgeable than we are here.
 
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Old 11-28-14, 06:29 PM
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Thank you. I clicked the link, but realized that after working outside in 20*f weather today, I cannot stay focused enough to understand the curve.

I will check the link again tomorrow, and again on Sunday.

About the 1.5hp pump, that was what the supply house sized for me, but they were not any help with having the pressure tank at the well. They said it needed to be at the house. Which, I agree, it would be nice to have it there, but it's just not really feasible. Like an earlier suggestion, you might as well drill a new well.

My other choice is city water, which is just as far away, and has 100psi at the street. At best, I would have 60psi at the house, but more likely to be 40-50psi. A new tap would also cost $2,000 vs a new pump, pressure tank, and switch at $1,000.

So, we will see how it goes.
 
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Old 11-30-14, 12:30 PM
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I think I would probably go for the city water. You are forgetting about the ongoing expenses of running a well, such as electricity and repairs. My Dad never hired contractors for our house, save one. He always made sure he had a good well man. Irrigation he did himself, but drinking water is a big deal.
 
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Old 11-30-14, 04:49 PM
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You are building a 4.5 bathroom house and you are worrying about the extra hundreds of dollars for electrical wire, or $2000 vs. $1000 for a new city tap, and you dont want to spend several extra thousands for a new well and instead would be willing to bury 800-900 feet of pipe which could be a major headache in years to come, just so that you could get the water from an existing 40 foot well on the property.

The money you are talking about would get completely lost in the noise for the cost of the new home. Something smells very fishy here IMHO- but I'm no expert to say the least.
 
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Old 12-01-14, 07:01 AM
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Are you within the city limits? In my area you are not permitted to use a well for potable water when municipal water is available. A well may be used for irrigation but the house must be connected to the municipal supply. It's their wonderful way of insuring customers and connection fees.
 
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Old 12-04-14, 10:10 AM
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Personally, I'd be all for getting my own water, from my own well. It is just how I operate...plus, in our hood, water meters are installed on city water, and that will be another revenue stream, even if they say otherwise.
First though, I'd get the water tested and do a flow test (recovery test). 40ft sounds shallow from where I am from. Just rent a jet pump and pull some water into 5 gallon pails. Measure time to fill and well static drop, and time for well to recharge.
As for pumps, each manufacturer has charts for size of pump needed for whatever flow rate you can sustain.
800' of pipe isn't an issue with 1-1/2" pipe. 130' head isn't all that bad either. Just make sure you have check valves on run.
Once you've figured out what size pump you can use, then you can figure out what size pressure tank you need. Larger is always better. You want your pump to cycle as little as possible, and to give it time to cool down between pump cycles...again, the manufacturer of each pump will have literature on this...
Although, I had no choice but to build my own well, as city water water doesn't come down my street, if given the choice, I know I'd want well water, than city lake water. City water is heavily doped with chemicals given it's source. My deep well doesn't have that problem.
 
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Old 12-16-14, 06:14 PM
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Just dropped in to say thanks for the help and replies. I first tied into the old street meter, but it wasn't enough pressure to get the water to the top of the hill, so then I got the 1.5hp pump and a 55g pressure tank, and plumbed into the shallow well.

I had to bump up the pressure to 80-100psi to get a good pressure range at the top. Looking good so far! Pumped out alot of sand and mud, but now it's clearing out.

Hopefully, I'm done with this thread.
 
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Old 12-17-14, 04:57 AM
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Just make sure you have everything protected against freezing before the really cold part of winter hits.
 
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Old 12-17-14, 03:53 PM
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Speaking of which, the one thing I forgot to put in the ditch with the power line for the pump, was another line for frost protection.

So, now I'm thinking about wrapping the pipe and doing whatever else I can to keep it from freezing without using electricity.

The pressure tank and switch are in the old farm house which is kept above freezing. So, I'm not worried about those pieces. Just worried about the 6' of pipe, or whatever it is that is in the well house.
 
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Old 12-18-14, 05:14 AM
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Insulating very well and enclosing it all in a well sealed well house protects mine OK until we get prolonged cold temperatures and nights below the teens. A cold night is not enough to cause trouble as the building, well & pad can store the days heat. It's the cold spells lasting a few days coupled with water not being used at night that can be an occasional problem.

Getting up in the night and using the toilet or leaving a faucet drip doesn't work well when you have a pressure tank. It's tidal volume can supply enough water for several toilet flushes and hours of dripping faucet without the pump having to cycle on and bring fresh, warmer water through the well head piping.

Like you I forgot to run separate, continuously on power to the well for heat. Luckily my well is close enough that a long extension cord will reach. It's good enough for the 1 or 2 weeks a year it's needed though last year I left it hooked up for a month. Inside the well house I put a thermostat outlet into which I plugged a heated office rubber floor mat like is used under people's desks to keep their feet warm. The mat is waterproof and only pulls 40 watts.





I wonder if there is a small, thermostatically controlled propane heater or even just a pilot light to put a little bit of heat into your pump house. A barbecue propane tank would probably be enough to keep a pilot light going for weeks and if the enclosure is well insulated that would probably be enough.
 
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Old 12-18-14, 08:08 AM
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20K BTU Vent-free Blue Flame Heater - 611581, Garage Heaters at Sportsman's Guide

This is the lowest BTU propane heater the is thermostatic controlled I could find at a good price.
 
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Old 12-18-14, 08:39 AM
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There's a 10K BTU Ice House Heater on the same site - #609952 - w/ thermostatic control for somewhat less. And if you want to go ice fishing you're equipped.
 
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Old 12-18-14, 09:02 AM
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I once sold a home where the owner had simply rigged up an incandescent light bulb to heat his "insulated" Spring House if the temperature in there ever dropped to +35F . . . . and if it dropped further (because the bulb burned out?), he had a 2nd thermostat and light bulb that kicked in at 28 or 30F.

Simple; but it had worked for decades, even when our temperatures here in Vermont sometimes get down to -50F.
 
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Old 12-18-14, 11:18 AM
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The problem is that there is no constant source of power at his well house.
 
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Old 12-18-14, 11:30 AM
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I'm wondering if you talked to your local propane company that hopefully also services gas stoves. Get a millivolt gas valve ($75) and a pilot light assembly ($25-$50) with a thermopile. The pilot light would generate about 1'000 btu per hour which would be enough to keep a small space from freezing. If the pilot light goes out the gas valve would shut off the flow of gas so you don't have a explosion hazard.
 
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Old 12-18-14, 06:06 PM
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I have a small propane heater like this one, with another line so that I can hook it up to a 20lb grill tank. It has a pilot light that I could leave on.

[ATTACH=CONFIG]43451[/ATTACH]

I like the thermostatic plug too. I may end up getting one and then running an extension cord to the well house. At some point, I'll install a new line to provide permanent power to the well house.

So, here are a couple of pics of what I'm working here and thinking about what needs to be done insulation wise. Take a look

[ATTACH=CONFIG]43453[/ATTACH]
.
.
.Here is the inside of it.
[ATTACH=CONFIG]43454[/ATTACH]
0
0
0

Just before posting this, I previewed it and thought, wow, I really need to push dirt up to it to cover the block walls and then they will be below grade. It would help a little.
 
Attached Images    
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Old 12-19-14, 04:56 AM
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You can also line the walls inside with rigid insulation. But after seeing how close it is to the house I'd run an extension cord with a small heat source. Light bulbs were the old standby but when the bulb burns out you're left with no heat so I've found the rubber foot warming pads to be more reliable. They also don't get very hot. Instead it's a gentle warmth over a larger area so you don't have to worry about a hot light bulb melting something if it should shift position when you're putting the lid back on.
 
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Old 12-19-14, 09:08 AM
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As close as the well house is to the house, I would bury some 12/2 with ground UF wire and hook it up to a breaker. I would install a exterior plug with a CGFI to plug in the heater or light. I would bury the UF about a foot deep and then I won't have to worry about it. I would also install a small light on top of the well house to signal when the heater was on.
 
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Old 12-19-14, 06:07 PM
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At 12"s of cover, you would need rigid conduit or GFCI protection for the shallow buried wire. Your GFCI outlet or dead front has to be installed between the panel and the point where it goes underground. I'm sure you know, but for the visitors, your scenario requires 24"s of cover.

And I plan on doing that, but it maybe the spring by that time. The extension cord will have to do for now.

I'm going to pick up one of those foot heated pads, pulling 40watts is nice! I thought it would have been higher. And a bulb would do the trick, but they aren't reliable enough to provide the level of protection that I would like for my pump.

So, the main thing now is a way to insulate the opening/cover. Because on a cold windy night, it would be pretty drafty in there.
 
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Old 12-20-14, 03:46 AM
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That well has been there for quite a while . . . . what has protected it from freezing in the past ?

I never considered Tennessee to be a place where freezing had to be taken seriously. I've gone through there in January, and the Tulips were already coming up !
 
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Old 12-21-14, 10:58 AM
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It's only a week or two out of the year that it stays in the teens here. It's been cold enough to gel the untreated diesel fuel in my truck and leave me stranded on the side of the road a couple of times. 15*f was the temp all three times.

The other thing is that no one is monitoring the well pump on site. If the pipes do freeze and bust, then the pump will kick on and pump out gallons and gallons of water per minute. No telling how long it will run before someone catches it.

It would fill the well house and then contaminate the well, which would be one heck of a mess to clean up on a cold winter day just to get water flowing again.
 
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Old 12-21-14, 02:50 PM
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Well I hope this doesnt happen to you and I dont want to be Mr. DoomandGloom, but that pit may fill up with water on heavy rains. Mine looks like a swimming pool with several feet of water on heavy rain, and as far as I know those pits are not allowed any longer because they do in fact fill with water and thus the contamination problem you mention, but are grandfathered in.

Hopefully you will be OK.
 
 

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