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#### aumfc

##### New Member
Hi All,

I've built a house on some acreage and the previous landowner ran a water line to another part of the property for his home. I'd estimate the total length of his line to be 2,000-2,200 feet with little rise.

The location of my new home branches off from the existing water line around the 1,200 foot mark, then goes another 600 feet uphill 60 or 70 feet. The would make my total run somewhere around 1,800' with a 70' rise at the end.

The existing line worked well, as far as I know, for the 7 or 8 years this person lived on the property, but it has sat dormant the last year and a half.

I'd like to run a new line to my house. What is the best / most cost-effective material and size pipe to use? What additional information do you need to make that determination, if any?

Thank you!
Jason

#### wwhitney

First thing you need to do is characterize the static (no flow occurring) water pressure of your existing water supply. Every 2.3 ft of vertical rise will reduce your static water pressure by 1 psi. You can take your static water pressure measurement anywhere on the existing system, but you need to pretty accurately know the elevation difference between that measuring point and your new house location. [You may also want to check with the utility or the current owner to find out if that static pressure is consistent, or if for some reason it might vary during the year, since you want to design based on the worst case.]

For example, say you measure the static pressure at a point 70 ft lower in elevation than your new house, and you get 80 psi. 70 ft of elevation gain is 30 psi of pressure loss, so at your new house the static pressure would be 50 psi, which is fine.

But if you measured 50 psi at 70 ft below your house, now your static pressure at the house would be 20 psi, which is not fine. So you'd need to use some sort of pump, either a booster pump or a pump plus some storage.

Whether you need a pump, and in what way, will guide your design. And then based on those choices, you can come up with an allowable pressure loss during water flow for your new water lateral. The necessary pipe size is then determined by the design flow rate, the length of the water lateral, and the allowable pressure loss during flow.

Cheers, Wayne

#### aumfc

##### New Member
First thing you need to do is characterize the static (no flow occurring) water pressure of your existing water supply. Every 2.3 ft of vertical rise will reduce your static water pressure by 1 psi. You can take your static water pressure measurement anywhere on the existing system, but you need to pretty accurately know the elevation difference between that measuring point and your new house location. [You may also want to check with the utility or the current owner to find out if that static pressure is consistent, or if for some reason it might vary during the year, since you want to design based on the worst case.]

For example, say you measure the static pressure at a point 70 ft lower in elevation than your new house, and you get 80 psi. 70 ft of elevation gain is 30 psi of pressure loss, so at your new house the static pressure would be 50 psi, which is fine.

But if you measured 50 psi at 70 ft below your house, now your static pressure at the house would be 20 psi, which is not fine. So you'd need to use some sort of pump, either a booster pump or a pump plus some storage.

Whether you need a pump, and in what way, will guide your design. And then based on those choices, you can come up with an allowable pressure loss during water flow for your new water lateral. The necessary pipe size is then determined by the design flow rate, the length of the water lateral, and the allowable pressure loss during flow.

Cheers, Wayne

Ok, thank you. So, step 1 is to figure out the static water pressure.

For budgeting purposes, let's assume its 80 psi and I don't need a pump. (The neighbor's water line runs the exact same path and then goes up a different hill and they have good pressure without a pump.)

Under that assumption, what would I need to do?

Thanks.

#### wwhitney

1) Determine static pressure
2) Determine design flow rate (10 gpm ?)
3) Based on step 1, determine allowable pressure drop during flow (5 psi ?)
4) Determine lateral length (2000 ft?)
5) Use a friction loss calculator to determine the necessary inner diameter.

I like this calculator: http://irrigation.wsu.edu/Content/Calculators/General/Pipeline-Pressure-Loss.php

With the above inputs it says you need a pipe of at least 1.7" inner diameter if using plastic. Probably round that up to 2" trade size. As to the variety of pipe to use, others have more experience with that. If you search the forum you will find earlier threads on that.

Cheers, Wayne

#### Jeff H Young

assuming 80 psi and 2 bath house no irrigation to speak of without figuring anything out between 1 1/4 inch and 1 1/2 I dont think 2 inch Im just guessing but to get idea for estimating costs polyethelene is what is mainly used.
When you actualy start planning this job in detail you might need to think of things like fire sprinklers as well. Ive got a 3 bath house with 120 psi coming in on 1 1/2" pipe with fire sprinklers 50 ft tops to the meter at curb. In California its often that plumber has to run a bigger main to accomadate fire sprinklers sprinkler contractor here has approved plans that dictate minmum size

#### Reach4

##### Well-Known Member
Menards has no stores in Alabama, and they will not ship the pipe to you. But this could give you some idea of what a good price is.

SIDR pipe hooks up with barbed "insert" fittings, and are attached with stainless steel worm gear clamps. I would go with brass fittings or stainless. Cheaper plastic irrigation fittings may not be as durable.

" total run somewhere around 1,800' with a 70' rise at the end.". You need to add the total change in altitude into your calculations.

#### aumfc

##### New Member
Hey Everyone,

The current water line is 1 1/2" sched 40 PVC. It runs a total of 2,145 feet from the meter to where the trailer used to sit. Elevation change +20 ft. I measured the pressure at the end of the line to be between 135 and 150 psi.

I would be cutting into this line at the 1,430 foot mark (also +20ft from the meter), turning and going uphill 600 ft with an elevation rise of 60 ft.

My neighbor's water line is the same size and material, and runs the same path to the 1,430 mark (+20 ft from meter). At that point, his line goes another 420 ft with an elevation rise of 80 ft. So, his line is a total length 1,850 ft and +100 ft elevation. His pressure and flow are great. I don't have the numbers but we lived in the house for over a year with 6 of us total and had no issues with either pressure or flow.

His line does have a regulator on it at the street to reduce it to 125 psi. His line had leaks at the PVC connectors over the years and he thought reducing the pressure at the street would help this. We may do this too at some point but not planning on it until after we get the water run to the house.

With this information, I'm thinking I will be fine to run 1 1/2" pipe from the 1,430 mark up to my house. Is my thinking sound?

I'm also thinking of running something other than PVC, like Reach mentioned. What would y'all recommend?

Recap of requirements:

- 600 ft going uphill 60 total ft, from 1 1/2 inch PVC at the bottom of the hill to 1 inch PVC at the top of the hill

I don't want to break the bank but at the same time, I'm willing to spend a little more to have 1) less issues now or in the future and 2) less install work to do since I'll be doing it myself.

Thanks everyone.

PS - My house has a large footprint as it's a single-level 4,000 sq ft home. We have a total of 4 showers and there are 4 of us living here. The water coming into the house right now from the well is coming in around 80 PSI and pressure has been fine throughout the house. I'm replacing the well water due to constant iron issues with the well water and flow rate from the well, fyi.

#### wwhitney

The current water line is 1 1/2" sched 40 PVC. It runs a total of 2,145 feet from the meter to where the trailer used to sit. Elevation change +20 ft. I measured the pressure at the end of the line to be between 135 and 150 psi.
What accounts for the change in pressure measurement, time of day?

If any of those measurements were taken while water is flowing, that's not what you want for your design starting point. You want the static pressure, when there is no water flowing on your lateral. Of course if the utility piping upstream of your meter is not super large relative to the demand on it, you could be seeing 15 psi fluctuation in your static pressure just due to fluctuation in demand on your water main. So I'll assume for now those are all static measurements.

1-1/2" Schedule 40 PVC has an inner diameter of 1.61". So take as a baseline that your extension is also 1.61" ID, and let's see if that will work adequately. In other words, if you choose some type of PE pipe instead of 1-1/2" Sch 40 PVC, choose one with a larger ID than 1.61", rather than a smaller ID.

I understand your total run from the meter will be 2030 ft, with an elevation rise of 60 ft relative to where you measured static pressure. That 60 ft of rise is a loss of 26 psi. So your static pressure at the house would be 109 psi to 124 psi.

Per the calculator referenced earlier, with 10 gpm demand the 2030 ft Schedule 40 PVC 1-1/2" lateral (no allowance for fittings, so that should probably be bumped up a bit) would drop 6.0 psi. With 20 gpm it would drop 22 psi.

Pressure drop through the water meter itself is non-negligible, you could specify the water meter model to get more exact data, otherwise we can guess 3 psi drop at 10 gpm, 7 psi drop at 20 gpm.

With those numbers, and no PRV, your max static pressure at the house would be 124 psi; the min dynamic pressure at 10 gpm would be 100 psi; and the min dynamic pressure at 20 gpm would 80 psi.

So those numbers show no lack of pressure, but the house static pressure would be too high and you'll need a PRV. If your water lateral can handle the up to 160 psi you seem to have at the meter, then just using a PRV at the house would suffice. If you set the PRV at say 70 psi, then depending on the model, it might drop 4 psi at 10 gpm and 7 psi at 20 gpm. So just after the PRV you should see 63-70 psi depending on demand.

I'm not knowledgeable on the advisability of running your lateral at up to 160 psi; so it might be better to have a PRV at the meter. If you rely on just that PRV, and set it so your house static pressure is 80 psi (maximum advisable), then you'd see a much bigger swing in pressure at the house, from 80 psi static to perhaps as low as 50 psi with 20 gpm of flow.

I'm also not knowledgeable enough to say whether looking at 20 gpm performance is reasonable, or whether for a single family house it would suffice to look at 10 gpm or 15 gpm performance. Although if you have large irrigation demands, or fire sprinklers on the same water lateral, I can say that 20 gpm is in the ball park and you may need to consider even higher flow rates.

Hope this helps.

Cheers, Wayne

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