City water up hill. 3,000 feet and 300 feet up.

[Gary P.]

I need help to get city water up hill. It comes out of the meter at around 75 psi and needs to go about 3000 feet in length uphill with an increase in elevation of 300 feet to where we are putting our home. I have no idea where to start to figure this out

Pipe sizing information, link by Terry

 

[Terry]

http://water.me.vccs.edu/courses/CIV240/lesson7.htm

The link above has a lot of tech information.
I don't think you want anything less than 1-1/2" pipe.

 

[Sponsor]

 

[Nukeman]

There's a couple ways to do it, but pump(s) will need to be involved. Roughly speaking you can figure 0.5 psi drop for every vertical foot of rise. So, at about half way up your hill, the pressure will have fallen from 75 psi to near 0. This doesn't include any frictional losses. You could do something with a couple of booster pumps along the way to get you there. Another option could involve cisterns and submersible pumps. Either way, you are looking at a lot of trenching for pipe and wiring. Also, the long distances will not only involve sizing the piping (due to frictional losses), the wiring for the pumps will also have to be sized due to the voltage drop over that distance.

Once you have a general idea of the design, you can start sizing the pumps, wiring, piping, etc. You will also have to think above freeze protection for each pumping station (depending on design).

 

[LLigetfa]

The 300 feet of vertical elevation is not the biggest problem. Deep well submersibles do that easily. The problem is the 3000 feet of run and what pressure it needs to withstand at the bottom. The formula is .43 PSI per foot of elevation, so close to 200 PSI if the pump is located at the base.

Depending on where the power is fed from also will factor wire size. Buck/boost transformers can help there but high voltage runs have their own challenges depending on whether you have a pole line or not. Separate metering is a possibility.

 

[Nukeman]

Yeah. There are many ways to do it. We would need to know more about the site to say what is better. For instance, the frictional part could be reduced by having a lower average flow rate over most of the distance, then collect the water in a cistern, and then would only have to handle peak flows over the final segment.

 

[LLigetfa]

...the frictional part could be reduced by having a lower average flow rate over most of the distance, then collect the water in a cistern...

If the cistern is placed as high as the city pressure can push it, you would only need one pump in the cistern to push it the rest of the way. The pipe size need not be as large as if pushing from the bottom. A second cistern at the house would require a second pump.

The line from city meter to cistern need only push enough GPM to satisfy average consumption. 1 GPM is 1440 gallons per day.

 

[Valveman]

300’ lift is the same as 130 PSI. Friction loss won’t add much to that if you use large enough pipe. You will probably want about 50 PSI more when it gets to the top, so you need to boost 180 PSI. I wouldn’t count on 75 PSI coming in when you start sucking from that line. Figure maybe 20 PSI coming in, so you need a pump than will boost 160 PSI which is the same as 370’ of lift.

Figure how much flow you want for the house. If 10 GPM is sufficient, then you need to size your pipe for minimal friction loss at 10 GPM, and to handle pressures up to 200 PSI.

You will need a multi-stage centrifugal booster pump for that much pressure. A pressure switch that can start and stop the pump from 170 PSI to 190 PSI, and a pressure tank that can handle that much pressure will also be needed.

The farther up the hill you can move the booster pump, the less pressure it will have to produce. But if you don’t want a booster set up half way up the hill, you will need to work at the pressure I described above.

 

[Gary P.]

At the bottom of the hill I have access to electricity as I have a home there now. The pressure from the meter is almost always 75 or higher and is fed with 3/4 line. The idea of one pump at the bottom was more like what I wanted to do. If I went with one pump closer to the bottom what size line would be sufficient.