# Pumping Cost From My Well



## freemare (Nov 16, 2016)

So i am trying to work out how much it costs to pump one gallon of water. I have some tenants living in my back house and I need to charge them for the power they use to pump the water. Anyway, maybe someone will know how much it costs. As I have a water meter to tell me how much they use. Thats why I need to know how many gallons one kilowatt will pull up from the well. Any super good math people out there :nanner:

My well is 2h/p
Is 300 feet down for water
and for 1 Kilowatt is 12 cents.


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## painterswife (Jun 7, 2004)

freemare said:


> So i am trying to work out how much it costs to pump one gallon of water. I have some tenants living in my back house and I need to charge them for the power they use to pump the water. Anyway, maybe someone will know how much it costs. As I have a water meter to tell me how much they use. Thats why I need to know how many gallons one kilowatt will pull up from the well. Any super good math people out there :nanner:
> 
> My well is 2h/p
> Is 300 feet down for water
> and for 1 Kilowatt is 12 cents.


You need to know gallons per minute as well.


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## Hitch (Oct 19, 2016)

Why don't you just average the usage based on historical data. Here's no need to quibble over a few bucks.


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## Fire-Man (Apr 30, 2005)

How big your storage tank is, its condition, how many times the pump has to restart makes a lot of difference on how much electricity the pump uses per month. 

When using my well a few years back---it has its on meter/service---the electric bill was $20 some per month for 3 homes and all 3 homes had 2 adults and 2 kids. Averaged around $8 per month per home, BUT the cost per Kilowatt was higher per kilowatt because of it being a well service instead of a residential service. We switched to the rural water service when the pump casing went out. Now we have 5 homes on the meter and it runs about $35 per month. 8 adults and 2 kids live in those 5 homes. 1 home does not have a clothes washer, none of the homes has a dish washer---none of the homes has a big "garden" tub in the bathroom and most all of the homes take their cars to car washes. I check the meter every few weeks when everyone is gone to work to see if there is any water movement--usually meaning a water tank/commode running and I determine which home has the problem and see that it gets fixed.


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## wy_white_wolf (Oct 14, 2004)

1 horse power ~ 0.75KW

2HP ~ 1.5KW 

1.5KW * .12 = 18 cents per hour

So how much does it pump in 1 hour?

WWW


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## freemare (Nov 16, 2016)

My pump can pump around 40 gallons per minute. Give or take


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## Nimrod (Jun 8, 2010)

Been a long time since I had a physics course.

How high does the pump have to raise the water from the static water level in the well? Your well is 300 feet deep but what's the static water level? 

A gallon of water at 40 degrees f weighs 8.3451 pounds. (at 32 f it weighs 8.3436 pounds which is why ice floats.) 

Your electricity is sold by the Kwh (killowatt hour). One Kwh costs 12 cents.

Work = F X D

1 Kw = 44,000 ft-lbs/min

1 Kw = (1 gallon of water/8.3451 pounds) X (44,000 ft-lbs/min) = about 5200 gallons of water/ft in 1 min.

1 Kw X 60 min/hr = 5200 gallons of water/ft/min X 60 min/hr = 312,000 gallons of water raised 1 foot /hour = 1 Kwh 

Now divide by the height the water is lifted in your system from the static level of the well to the height its used at. This is how many gallons per hour 1 Kwh will lift the requisite height.

Now divide by the gallons of water used in a month and the result is how many Kwh it takes to pump the water. 

Multiply by 12 cents and you know how much the electricity costs.

Of course this doesn't factor in the friction and the start up surge of the pump motor so the cost will be somewhat higher. 

I now have a pounding headache and am overdue for dinner. I hope you are happy.


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## TnAndy (Sep 15, 2005)

Then you would take the number of gallons used, divide by 40 gal/min to give you the number of minutes of use of power per day/week/month (depending on the time period you read your water meter.) Unless they are using a bunch of water for some reason, which your meter should tell you, I'd be surprised if the use is 10 minutes/day.....that's 400 gallons/day.

Meaning (10/60) x 18 cents/hr = about 3 cents/day, or a buck/month.

If I had decent tenants...meaning they pay the rent on time and don't tear the place up too much, I'd be danged if I wouldn't throw in a buck...or ten....a month in power use.


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## 1948CaseVAI (May 12, 2014)

I have no idea how to compute your costs, but I know I am sure glad I am not your tenant if you are going to worry about ten bucks here or there (or whatever the piddling amount turns out to be).


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## Murby (May 24, 2016)

Purchase a 220 volt Kilo-watt meter and hook it to your pump's electrical breaker circuit.. Then just divide the kilowatts used by the number of gallons and it should be very very accurate.


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## TnAndy (Sep 15, 2005)

Murby said:


> Purchase a 220 volt Kilo-watt meter and hook it to your pump's electrical breaker circuit..



Got a source for 220v meters ?


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## Murby (May 24, 2016)

https://www.amazon.com/Electric-Meter-100A-Volt-3-Wire/dp/B00GMZRXE8

cheaper here;
http://www.ekmmetering.com/basic-kwh-meter-100a-120-240-volt-3-wire-60hz-ekm-25ids.html

might want to call them to make sure its what you want.


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## Murby (May 24, 2016)

Cheaper options:
http://www.ebay.com/itm/Digital-WAT...064685?hash=item2a73a8bced:g:uCcAAOSwuzRXdngw

There are a lot of them on ebay like this one:
http://www.ebay.com/itm/AC-380v-220...384590?hash=item33aeb44fce:g:ohkAAOSwk1JWd9UJ

Not sure how much effect it might have but these styles use induction coils.. notice that round ring on top? You run the power wires through that and it measures the EM field.. 
Ever see a "Clamp-On" multimeter with the lobster clamp? They work on the same principle. 
The problem is that inductive coils are not as fast or as accurate as a shunt is.. for a motor that runs for long periods, this wouldn't mean much.. but for a motor that cycles on and off and has a high-inrush current, like a pump motor, this error could add up over time.. still not sure how much of a difference it would make.. 

You might not realize it, but pretty much ANY household electric meter would work.. if you can find an older model for cheap, it would work just fine if you attach it to its own circuit on the water pump.


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## mustangglp (Jul 7, 2015)

wy_white_wolf said:


> 1 horse power ~ 0.75KW
> 
> 2HP ~ 1.5KW
> 
> ...


My 1 HP rate pump pulls 2 KW according to the PG&E smart meter Mesured with amp meter 1 per leg. You guys are lucky to have such cheap electric rates. 200 kw cost me about 90 dollars a month with all the fees tacked on.


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## Murby (May 24, 2016)

mustangglp said:


> My 1 HP rate pump pulls 2 KW according to the PG&E smart meter Mesured with amp meter 1 per leg. You guys are lucky to have such cheap electric rates. 200 kw cost me about 90 dollars a month with all the fees tacked on.


That doesn't make sense. 
1 horsepower = 746 Watts... 2hp*746w = 1492 watts

So a 2 hp motor is really a 1.5 KW motor..

There are some variables that could increase that, but not by 500 watts.. That would make your 2hp motor almost a 3hp motor.

Might want to check the accuracy of the meter.


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## Alaska (Jun 16, 2012)

1948CaseVAI said:


> I have no idea how to compute your costs, but I know I am sure glad I am not your tenant if you are going to worry about ten bucks here or there (or whatever the piddling amount turns out to be).


 I agree. don't nickel and dime a good tenant. If you are worried about how much water they are using install a flow meter on the pipe and inform them rent is based on including so much water use. If consumption goes up to much rent may have to go up.


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## freemare (Nov 16, 2016)

Alaska said:


> I agree. don't nickel and dime a good tenant. If you are worried about how much water they are using install a flow meter on the pipe and inform them rent is based on including so much water use. If consumption goes up to much rent may have to go up.



I do have a flow meter for the house in my well house. I just want to make sure they dont crazy with water, and pay for wear and tare on my pump and help cover maintenance on the pump as well. My neighbor had a incident were she included the water in there monthly rent. Then when she got her bill it was almost double. She found out they were taking hour long showers, washing dishes in the dishwasher several time...etc. As they in turn did not have a water bill. So they were using a lot of water.


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## Belfrybat (Feb 21, 2003)

I think you are wise to charge a fee for water, but don't nickel and dime it. Just tack $15.00 +/- onto the rent for water use and call it even. One time I rented a place on a well and the landlord charged $10.00 a month for water -- this was in 1986. That was about the same cost as water in town at that time, so the amount was fair. Where I just moved from the city water cost was $28.00 for 2000 gallons and $6.95 per 1000 gal. above that. A flat fee on a well makes sense.


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## wy_white_wolf (Oct 14, 2004)

freemare said:


> My pump can pump around 40 gallons per minute. Give or take


.18 / (40*60) * 1000 = 7.5 cents per 1000 gallons.

WWW


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## wy_white_wolf (Oct 14, 2004)

mustangglp said:


> My 1 HP rate pump pulls 2 KW according to the PG&E smart meter Mesured with amp meter 1 per leg. You guys are lucky to have such cheap electric rates. 200 kw cost me about 90 dollars a month with all the fees tacked on.


Pulling more amps than the rated amount is a sign a problem with the pump/motor. Bad bushings, brushes, or winding dragging creating a larger drag on the motor.

They also could have the meter set to return highest reading which would be your startup surge and has little effect on the overall power usage unless your restarting the motor every 5 or 10 seconds.

WWW


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## mustangglp (Jul 7, 2015)

This is the pump Have they dont say much about how many amps it pull I suspect it might be under rated I can run 10 rainbirds with 1/8 nozzles 
It replaced a 2 hp but that was before the smart meter went in. 


http://store.waterpumpsupply.com/20gpmsubwelp.html


Murby said:


> That doesn't make sense.
> 1 horsepower = 746 Watts... 2hp*746w = 1492 watts
> 
> So a 2 hp motor is really a 1.5 KW motor..
> ...


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## mustangglp (Jul 7, 2015)

wy_white_wolf said:


> Pulling more amps than the rated amount is a sign a problem with the pump/motor. Bad bushings, brushes, or winding dragging creating a larger drag on the motor.
> 
> They also could have the meter set to return highest reading which would be your startup surge and has little effect on the overall power usage unless your restarting the motor every 5 or 10 seconds.
> 
> WWW


It dose not start and stop I watch that close I thought it seemed high that why i measured with a amp meter A little less then I kilo watt per side if i remember right 
Its been in for 4 years and ruining fine so i dont think theirs a problem with it.


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## MichaelK! (Oct 22, 2010)

My 1.5hp Grunfos pump pulls 10.0 amps at 240VAC, so I'd estimate your 2hp pump consumes about 13.3 amps, or ~3200watts.

(3200watts/1000watts/kw) X (.12$/kwh) would equate to 38.4 cents per hour.


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## idahodave (Jan 20, 2005)

Just a quick note: For an inductive load like a motor the power used is I*E*PF not just I*E. Power factor for a motor is a function of load, but if the motor is properly sized a PF of 0.8 to 0.9 can be used.

Most motors run hot, so a few hundred watts could also go up in heat.

Dave


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## fordy (Sep 13, 2003)

...............There is a real simple way to apportion the water well electric usage.............install a volume meter on the output side of the pressure tank(total gallons pumped during the month) , then install a volume meter on THEIR water line ! The numerator is how many gallons they used , the denominator is the TOTAL gallons the well pumped during the month from the pressure tank meter . Then , just multiply the total electric bill for the well by that fraction ! You'll have to have an electric meter for the well to know how many kilowatts the well used during any given month . , fordy


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## Belfrybat (Feb 21, 2003)

Fordy - that doesn't take into consideration the actual cost of pumping the water. Electricity is not the only cost. There is maintenance and equipment replacement to consider. 

The OP hasn't been on here for a while and I'd be interested in what he decided to do.


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