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Running a new water line-need help in sizing it.

cowsrus

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I'm getting to run a new water line to my house. It's 3000 ft and i will be hooking it to a city water tap meter with a 3/4 in. outlet connector. My question is will it do me any good (pressure or volume wise) to run anything bigger than a 3/4 in. line?
i was going to run an 1 1/2 in. or 1 1/4 in. line, but will i be wasting my money? It seems to me that the 3/4 in. restriction at the meter is going to limit the pressure and the flow.
Any advice? please?
 

mwj

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Run the bigger line and you will gain a lot of volume. The 3/4 fitting will only reduce the volume a small amount if it is only a short distance.
 

bigbull338

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id run 1.5 in line.an that would get you better pressure.but only when the water syustem had good pressure.
 

Angus Cowman

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another option is to add a boost pump and pressure tank at your house so you will have adequete pressure
I would also see if they can put you a 1 1/2' tap on the city service that would help with the volume

I just checked in our spec books and they actually reccomend a 3" line any thing over 2500 ft you also need to install a check valve in the line at the house in case of low pressure your water doesn't back feed into the municipal system at times of high usage on the main line
 

Running Arrow Bill

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As a retired Texas Licensed irrigator, a 3,000 foot line will have a LOT of friction loss. Consult friction loss charts to size your line. Agree with other poster...try to get city to at least upgrade the meter to 1"...preferably 1.5". For the 3,000 foot line, do not go less than a 2" line! Preferably 2.5" or 3.0". With a small line, you might have to "suck the water out of the line" to get any. Also, the suggestion to put an inline centrifugal booster pump at the terminal end of the line is a good one. To make sure you have adequate pressure at terminal end, you probably need a minimum of a 1 HP pump. Also, use a backflow preventer at your end.

Things to calculate your needs with:

1. PSI on outlet side of meter.
2. Volume out of a 3/4" outlet at meter.
3. Length of your line.
4. Size of pipe in water line.
5. Size of booster pump (if used).

Good luck...keep us posted!
 

bear

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There are alot of factors involved. What is the elevation of your house in relation to the location of your water meter? What is the pressure on the main? How big is your house? How many fixtures in the house? Will there be any yard hydrants pulling off the house plumbing.

You will probably need to go to a larger meter. Most water jurisdictions use 5/8 meters when tapping for 3/4" service. The line loss in 3,000 ft. (depending on terrain) may exceed or be very near the flow rate of a 5/8 meter.

Meter size and line size is very important even when considering a booster pump as the pump could suck the supply line dry if your meter and or line size is wrong.

It may be worth the money to consult a local engineer to size according to all of these factors.

Bear
 

cowsrus

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The water pressure at the meter is about 60 psi and its pretty level from the meter to the house and yes i have outdoor faucets as well i am putting 4 freezeproof watering tanks. I will talk to the water meter people tomorrow about putting in a bigger meter, that would sure help I know. Its a city water dept., so i am sure they are not used to people running lines that far.
 

larryshoat

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Angus Cowman":3rrjzy18 said:
another option is to add a boost pump and pressure tank at your house so you will have adequete pressure
I would also see if they can put you a 1 1/2' tap on the city service that would help with the volume

I just checked in our spec books and they actually reccomend a 3" line any thing over 2500 ft you also need to install a check valve in the line at the house in case of low pressure your water doesn't back feed into the municipal system at times of high usage on the main line

I think A/C is giving good advice . I won't cost much to put in the bigger pipe, 3000 ft is a long way, they have charts that tell how much PSI is lost for a given size pipe . It would be sad to get that in and not have enough pressure . I only went 800 ft and I used 2", if I remember 2" pipe loses like .15 PSI per 100 ft ( don't hold me to that it's been 10 years :oops: ) .

Larry
 

bear

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At a flow rate of 20 gpm in 2" pipe, line loss would be about .3psi/100ft. or 90psi. With a flow rate of 25 gpm in 2" pipe, line loss would be about .5psi/100ft. or 150psi. As volume and velocity increase line loss or frictional loss increase.

2" pipe will not work!
You can decrease velocity and increase volume and reduce line loss by going to a larger pipe size.

At a flow rate of 20 gpm in 3" pipe, line loss would be about .05psi/100ft. or 15psi. Net pressure at the end of 3000ft. would be approx. 45psi.
At a flow rate of 30 gpm in 3" pipe, line loss would be about .1psi/100ft or 30 psi. Net pressure at the end of 3000ft. would be approx 30 psi.

At a flow rate of 30 gpm in 4" pipe, line loss would be about .03psi/100ft. or 9psi. Net pressure at the end of 3000ft. would be approx. 51psi.

You will probably want to produce at least 30 gpm at the house. You will still need to size the house and yard hydrant lines according to incoming pressure or install a booster pump. Your local water supplier should be able to tell you what their respective meter sizes will provide in gpm at 60 psi.
I would probably opt for the 4". If you go with the 3" at 30 gpm with a booster pump and max out the flows in your house and yard hydrants, you could starve the booster pump for water if the pump ran very long. The line losses above do not take into consideration any fittings. Run as straight as possible and use as few fittings as possible.

Hope this helps! Bear
 

dun

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Our longest run from the well head is around 2000 feet and we used 2 1/2. Only use it for stock tanks, not sure how adequate it would be for a house.
 

cowsrus

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But will i benefit from running the larger size pipe when i'm coming off a 3/4 in. meter outlet fitting? It seems to me that the 3/4 in. outlet is going to restrict the pressure and the volume at the end of the run. (if you figure it without a booster pump)
 

jedstivers

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cowsrus":2tdzfvz3 said:
But will i benefit from running the larger size pipe when i'm coming off a 3/4 in. meter outlet fitting? It seems to me that the 3/4 in. outlet is going to restrict the pressure and the volume at the end of the run. (if you figure it without a booster pump)
I had been thinking about what I had posted and was going to re-post because after thinking about it more I don't think I would use less than 3" & with what bear posted that is even more to think about. You will benefit from a bigger pipe even with a 3/4" meter, as far as a larger meter in our area 3/4" and 1" are all that are offered and a 1" will put out lots more water but the price per gallon is more which doesn't make any sense at all but that's government in action.
 

john250

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We have a rural water system, and we have lots of 2" pipe feeding 3" pipe. Even 2" feeding 4". 3" is the smallest line we will install for new runs of pipe.
You don't get more pressure, but you get a lot more volume. And the pressure will stay up enough even if you use it heavy.
 

bear

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You will benefit from the larger pipe with a 3/4" meter. However, there will be pressure loss when the water travels through the tap on the main and when it travels through the meter.

We increase pipe size to reduce friction loss in order to maintain as much of our starting pressure as possible. We know that some pressure loss will occur, so we try to offset that loss with increased pipe size to maintain desired volume at the end of the line.

We have to take similar steps with the tap and meter size to offset the pressure loss through the tap and the water meter.

A 5/8" residential meter will have a pressure loss just through the meter of approx 11 psi. with a maximum flow rate of 10 gpm. This does not include friction loss from the tap or the meter setter.
A 3/4" residential meter will have a pressure loss through the meter of approx 11 psi with a maximum flow rate of 15 gpm.
A 1" residential meter will have a pressure loss through the meter of approx 11 psi with a maximum flow rate of 25 gpm.
A 1 1/2" residential meter will have a pressure loss through the meter of approx 11.4 psi with a maximum flow rate of 50 gpm.
A 2" residential meter will have a pressure loss through the meter of approx 12 psi with a maximum flow rate of 80 gpm.

Each size has approx. the same pressure loss but has different max flow rates. The 1 1/2"-2" meters will have less pressure loss at 25 gpm than the 1" at 25 gpm max flow.

If you are abe to use a commercial grade water meter, a 1 1/2" commercial grade water meter will have a pressure loss of approx 6.9 psi at 160 gpm.
There would be very little pressure drop at 30 to 40 gpm between the main and the 4" service line with the 1 1/2" commercial grade water meter and setter.

All of these charts and specifications are great information, but have very little regard for the "cost factor".

If your local water supplier will only tap 3/4" or 1", you could get by with the 1" tap and meter. In fact, unless you were going to need more than 25 gpm, I don't think I would pay for the 1 1/2" or 2" tap and meter if I thought I would need a booster pump with the larger taps. With the 4" service line you are at a calculated 51 psi. If you go with the commercial grade water meter, you still may experience an additional 1-3 psi drop in pressure. That would put your pressure at the house approx. 45-50 psi. Most people are not happy with this kind of pressure.

Be sure and check the pressure loss ratings of the meters used by your local water supplier. Have them verify the estimated flow rate out of the meter. This will be very critical in your meter size decision, unless they can only provide 3/4" or 1" meters. The specifications I used are from "Sensus" water meters.

If I were plumbing your house here in Missouri this is the way I would approach it. We have to put alot of faith in charts and specifications to guess at the end result. Long water services such as this one are always a challenge!

Bear
 

Angus Cowman

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Bear is correct in his statement but let me simplify it just a little

If you have a hydrant that is 100 ft from the main and it is fed by a 1" line you turn the hydrant on you will have say 50psi of pressure

ok lets attach a 100ft 3/4" garden hose to that hydrant at the end of that hose you will have about 10% less pressure and flow than at the hyd
and if you connect 200ft of garden hose to that same hydrant then you will have approx. 15-20% less pressure and flow than at the hydrant

but if you connected a 2" line at the hyd and ran it for 200 ft and then attached 5ft of 3/4 hose to the 2" line you will have the same pressure at the end of the 3/4" hose that you had at the hydrant that you originally started at

By running the increase line size you are reducing the resistance and increasing the holding capacity of the water sytem

then when you reduce the outlet size of the line at point of delivery you are increasing the pressure

it is like using a spray nozzle on the end of a garden hose the hose by itself will let water run out 2 ft beyond the end but when you put a spray nozzle on the hose and limit the flow you increase the pressure

By running the larger line and then reducing it at the point of delivery you can slow the volume and increase the pressure


You never stated where you are located

I know here in Mo i most parts of the state you can drill a well cheaper than you can run a 3 or 4" line for 3000 ft and you would be alot happier with the results
 

jcummins

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I had the very same situation, about 6 months ago. Ran 2000 feet, and the meter outlet was 3/4. I used 1 1/2 and my pressure is very good. Worked for me.
 

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