# well water pressure loss over distance

Can anyone tell me of a simple way to determine pressure loss over distance in Gallons-per Minute of well water? Example: Assuming I have 10 GPM at the well head, if I run a 2" ID water line 100', what loss in GPM will I get? The tables I have been able to find all refer to loss in water pressure (PSI). I need to go about 600' from the well head to the new house and want to know if it is even practical to try to utilize the old well.
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According to Glover's Pocket Ref -2nd ed- 10 gpm thru a 2" plastic pipe will loose .03 gpm per 100'. Glover's Pocket Ref is a very handy book.
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If you have anything near 10 gpm at the wellhead, you will have more water than you will ever use, even if you went 3000 feet.
I have a very small spring that produces about one gallon per minute. I pipe it 1200 feet uphill, and never have any problem.
Good luck !!
--james--
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You need to worry more about how much rise (or fall) the line has. Each foot of rise will reduce Pressure (not volume) by about .4 lb i believe it is.
--
Steve Barker

"bodega" < snipped-for-privacy@yahoo.com> wrote in message
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bodega wrote:

bodega -
I hope you don't lose any gpm....cuz all the water going to the pipe at the well head better be coming out of the pipe at the house....otherwise you've invented a "matter destroyer"
Your pump has certain preformance capability
flow (gpm) at various pressure (head) levels
ranging from.......
lots of flow at very little pressure to very low flow at high pressure
the length, material & condition of the pipe & elevation change will determinw how much head (pressure) drop will be suffered from well head to house
here is a pressure loss calcaulator, you can play around with it
http://www.freecalc.com/fricdia.htm
2" PVC (600ft) with 10gpm flow will lose less than 1 psi 1.5" pipe ~ 3psi 1" pipe ~ 30psi
1.5" pipe is probably signifcantly cheaper than 2" & you can probably handle ~2psi extra pressure loss
so unless you're pumping a long way uphill in addition to the 600 ft AND you have a really wimpy pump you should be fine
cheers Bob
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On my spring which produces 1gpm, I have a two inch plastic pipe that goes 1200 feet to our cabin, and has a total rise of 300 feet.
I have a 1 hp pump, that pumps water pefectly fine to the cabin, and I set my pressure tank at 50 psi, and it works just great !
The spring site has a 300 gal storage reservoir, so our 4 member family never runs out, even at this very very low water rate of 1 gpm.
If you have as much as 3 or 4 gpm, you can simply quit worrying about running a pipe 600 feet. You can do all the calculations you want, but what you really want to know is will you have plenty of water and good pressure, and I can tell you that you will !!
--James--
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3-4gpm??? A water saving shower head uses 3 gpm.
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Mike wrote:

Mike-
Maybe he's talking about the well / spring flow capacity not usage demand / supply at the house.
He's using the 300 gal storage reservoir at the spring site as a means of supplying the drawn down demand of the cabin use?
A 1 hp pump would run dry in a heart beat if only supplied w/ 1 gpm.......
he needs ~140psi just to over come the rise.
so the 3 to 4 gpm house supply would be rather lean
IMO a house / cabin with more than one person needs more like 10 gpm to give decent performance.
cheers Bob
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In a previous post Bobk207 wrote...

Bob's estimate sounds about right for the required flow rate available in the house -- think showers and laundry + toilet flushing all at once. That's why there should be a pressure/reserve tank at the house. As long as the tank is big enough you can have a very low volume flow to the tank from the well or spring.
BTW, this is the classic calculus problem of filling a tank at one rate and drawing it down at a higher rate. How long before the tank is empty?
--
Bob Morrison, PE, SE
R L Morrison Engineering Co
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Thanks for the info. I suppose a guy could always increase the pump size if more pressure was need too. Bobk207 wrote:

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