# how to get maximum pressure and water volume at 300 foot distance.

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• posted on May 11, 2015, 1:50 am
My well pump at the pressure tank is 45 psi. From one of my exterior facets I want to run a line to my garden located 300 feet away, to feed a trickle irrigation system consisting of 20 - 120' trickle tube lines which are each run off of a 1-1/2" header pipe. Each 120' line has its own turn off valve so that as many lines as need to be, can either be turned off or turned on at the same time. Each of the 120' lines water requirements is about .6 gallons per min. Currently I am trying to feed the entire system with 300 ' of garden hoses all of which are 1/2" . It seems to me like there is an awfully lot of drop in pressure at the outlets individual line outlets, and currently I am only able to feed 1 or 2 of the 120' lines at a time. I would like to have enough water and pressure to feed more of the lines at a time if possible Questions: 1. will this work this way. 2. Would it be better to feed the 1-1/2' header tube located 300 ' away with a larger diameter piping? 3. Would it be advisable to add a booster pump to the line and / or if so what kind and how big?
Denny
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<%-name%>
• posted on May 11, 2015, 3:38 am
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Go to a larger pipe. Make sure all the pipeing is larger, including the pipe from the well tank to the hose. Each time you double the diameter of the pipe you get about 4 times the volume, or flow.
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<%-name%>
• posted on May 11, 2015, 3:43 am
On 5/10/15 10:44 PM, Denny of PA wrote:

If the 300' hose is level and the garden end is open, 45 psi would give you 2 gallons per minute. Your flow would be less because the trickle tubes will need some of that 45 psi.
If you used 3/4" hose and the end were open, you could get 6 gallons per minute. As the hose won't be open, you'll get less, but you should be able to feed more tubes than you can now.
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<%-name%>
• posted on May 11, 2015, 11:27 am
Denny of PA wrote:

There's a pipe sizing chart here if it helps: http://www.irrigationtutorials.com/irrigation-pipe-sizing-chart-for-laterals/ or http://tinyurl.com/nzybnjf It's probably not an issue but creating more pressure costs money for the extra energy required. Irrigation systems for farm use ran at 70 psi or so in the old days. Modern ones run in the area of 35 psi. That supposedly saves about 30% in pumping costs. These things typically run at 800 gpm or so.
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<%-name%>
• posted on May 11, 2015, 3:15 pm
Dean Hoffman wrote:

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<%-name%>
• posted on May 11, 2015, 3:28 pm
On Monday, May 11, 2015 at 11:15:38 AM UTC-4, Tony Hwang wrote:

I was thinking that too. He needs 12GPM, which isn't unusual, but there are plenty of wells yielding less than that. It's worth considering before scoping out the solution. He could also raise the pressure up from 45 a bit too.
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<%-name%>
• posted on May 11, 2015, 5:10 pm

I thought it was six GPM, but it looks like it is Point Six (6/10) GPM.
That would be around 1.8 GPM for the 3 lines. Big difference. That is why I would think he needs a larger line than the 1/2 inch he has, especially for over 300 feet.
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<%-name%>
• posted on May 11, 2015, 6:05 pm
On Monday, May 11, 2015 at 1:10:09 PM UTC-4, Ralph Mowery wrote:

The way I read it, he has 20 drip lines each using .6 GPM. That's 12 GPM. He could also put in a valve, either mechanical or automatic that would only run some subset of those at a time.
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<%-name%>
• posted on May 11, 2015, 8:34 pm

You are correct. I don't know where I came up with only 3 lines.
It will take a good well to put out 12 gpm for very long at a time. No wonder he can only run a couple of thoses drip lines. I was looking at some pipe flow charts and only used the 1.8 gpm that I some how made a mistake with. I am thinking around here (middle of NC) that a good house well puts out about 8 GPM. Maybe he has a lot larger than 6 inch well.
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<%-name%>
• posted on May 14, 2015, 2:16 am
On Monday, May 11, 2015 at 4:34:47 PM UTC-4, Ralph Mowery wrote:

NJ here and 4" well, 50-100ft, typically can do 15 gpm. But of course what matters is what his well can deliver and I agree, there are plenty of wells that won't be able to keep up.
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<%-name%>
• posted on May 14, 2015, 2:37 am

Today for curiosity I ran the water out at the facet, and determined that it was putting out just 6 gallons per min, so i guess it really does nor matter how much pressure I have, at most i can only use 10 of the lines at a single time, at the volume required is 0.6 gpm Is that the right way of looking at it ? BUT I am not able to get that yet, Could it be because i am only feeding the line with 1/2 " hoses,,,,? If I increased the diameter of the feed line hoases to 1" , would i then be able to get my full 6 gmp to the field?
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<%-name%>
• posted on May 14, 2015, 4:05 am
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http://www.tlv.com/global/TI/calculator/water-pressure-loss-through-piping.html#
You probably need a pipe that is about 3/4 inch trade size which is much larger than the actual measured size.
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<%-name%>
• posted on May 14, 2015, 2:00 pm
On Wednesday, May 13, 2015 at 11:44:05 PM UTC-4, Denny of PA wrote:

Yes. You can't get 10 lbs of crap from a 5 lb bucket.
BUT I am not able to get that yet, Could it be

Whatever flow you have from a 1/2" hose at 300 ft, you're certainly going to get a lot more from 3/4", and more still from 1". You'd be closer to 6 GPM, but from physics, you're still not going to get the full 6 GPM that you have with no resistance at all.
You said you're using it for strawberries and this sounds like a decent size project. Have you considered using black poly pipe/tubing? You can probably get a 1" x 300 ft roll of that for less than it's going to cost for hoses.
Any need for it to be buried? Lawn sprinkler guys could pull that pipe for you underground in an hour, assuming it's just clear shot, no trees, etc. IDK what they would charge, they'd have to bring the pulling tractor over, etc, so it wouldn't be real cheap, but then it's buried, permanent, etc. Just throwing it out as an option.
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<%-name%>
• posted on May 14, 2015, 10:30 pm

today as a trial I just replaced part of my feed line with an additional 50' of 1-1/2" header pipe , at the 300 ' end and I eliminated 50' of one of the 1/2" hoses that i was using to feed the head section. , and i was happy to see that i was now able to get 7 of the 120" trickle line working at a time. yes trhe larger supply pipe appears to be the answer, I was just using the hoses because they were available, but now that i know the cure to my problem i will invest in the poly pipe., and maybe i will be able to get 10 of the lines working at a time like i would like
Denny
thank you all for your
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<%-name%>
• posted on May 15, 2015, 12:57 am

its a trickle system, truly whats critical about running 10 lines at a time?
you could run just one line at a time, 24 hours a day.-
what difference would it make?
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<%-name%>
• posted on May 15, 2015, 1:57 am
replying to bob haller , Denny of PA wrote:

simply because I have 20 - 120 ' lines off of my 1-1/2" header line , and if i run 10 of them at time i water half the garden all at once in about 2 hours. my total supply is 6 gpm and each 120 ' line takes 0.6 gpm x 10 = 6 gpm , that is the max that I can possible water at the same time.
THAT ! is the difference. ;-)
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<%-name%>
• posted on May 12, 2015, 1:14 am
replying to Ralph Mowery , Denny of PA wrote:

OK, thank you all for your valuable input.
Yes for clarification the trickle line tubing uses 0.5 gpm/100' which means in 120' that is about 0.6 gpm in each one.
I imagine that what is reducing my pressure at the outside facet is because at that point, the facet is located about 50 ' already from the pressure tank which is located inside the home basement, and to that point that is only serviced by 1/2" copper tubing, so I cannot increase the size of my piping back to the pressure tank point as someone else had suggested.
I was working on it again today. Someone mentioned that most trickle irrigation systems are designed to run on 15 psi, that is correct and that is what I had been using to only get the 1 or 2 lines to be able to be feed at a single time. But today i decided to remove the restricted PSI attachment in hope that my flow with the greater pressure would be increase up stream at 300 feet away. When i removed the 15 psi filter, I now found that I was able to get up top 5 of the 120' lines going at once. I tried opeing a 6th line, and the volume of water flow was so slow that it then even detracted from the flow on the other 5 lines.
Tomorrow I am planning to try to obtain some larger supply hoses to see if the increased water volume be pushed would benefit I am going to buy a roll of 1" diameter tubing to use as a supply line to replace the 1/2 " to the garden, to see if this would increase the number of 120' trickle line be utilized at a time may be increased. . I would be really happy if i could get 10 of them to be used at once, which means I could water half of the garden at a time for several hours , and then water the other half.
BTW in case you are interested, what I am watering is 2,000 strawberry plants, which are planted in 120' rows located 4' apart. Many many thanks to you all again for your valuable input. I will let you know how the greater size 1" tubing works out, if I can obtain it tomorrow, or later this week.
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<%-name%>
• posted on May 14, 2015, 2:22 am
On Monday, May 11, 2015 at 11:44:07 PM UTC-4, Denny of PA wrote:

of 1/2" pipe, followed by 300 ft of other pipe, you'll never support 12 gpm. Once you throttle it back like that, you can put 2" pipe after it and it's not going to make much difference. Best bet is probably to water it in several sections instead of all at once.
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<%-name%>
• posted on May 11, 2015, 4:41 pm
On Mon, 11 May 2015 02:44:01 +0000, Denny of PA

Yes
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<%-name%>
• posted on May 11, 2015, 6:52 pm
On 05/10/2015 9:44 PM, Denny of PA wrote:

Simply going from 1/2 to 5/8" hose provides a 50% area increase/reduction in dP; 3/4" would be 36/16--> >2X ((6/8)/(4/8)^2)
That should help quite a lot. Most drip systems are intended to run at 10-15 psi; check your emitter supplier's datasheets for that so if you run more pressure you'll just have to have a reducer anyway.
As others have noted, make sure you've got the well capacity overall for 12 gpm minimum.
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