Water Pressure on Undeveloped Land

SoonerAviator

Final Approach
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SoonerAviator
Have a question about a potential land purchase. Land is at the top of a fairly tall hill, and has rural water at the bottom of the property with reportedly good head pressure. Water also available at top of property but no guarantee on water pressure. Any solutions to maintaining adequate water pressure for a household? I figure that a sizeable pressure tank like what is typically used for water wells might be an option, but I'm not sure how that functions if you don't start off with decent pressure to begin with. I suppose water could be pumped up from the bottom of the property (where pressure is better) but that probably gets a bit more complex.

Anyone have experience with such a task? Side note, there might be a water well being drilled as well for an outside water source and there is a natural spring at bottom of property.
 
In typical POA fashion, I don't have any answers, but I sure have more questions!

- Why bother with the water company if you are going to drill a well? I have a well with basically unlimited free water (other than the pump electricity) and would have zero interest in buying water from the man, regardless of if it were available.
- How long and tall is the hill from the rural source?
- What is the pressure at the source?
- Why can't you check the pressure at the top of the hill?
 
Have a question about a potential land purchase. Land is at the top of a fairly tall hill, and has rural water at the bottom of the property with reportedly good head pressure. Water also available at top of property but no guarantee on water pressure. Any solutions to maintaining adequate water pressure for a household? I figure that a sizeable pressure tank like what is typically used for water wells might be an option, but I'm not sure how that functions if you don't start off with decent pressure to begin with. I suppose water could be pumped up from the bottom of the property (where pressure is better) but that probably gets a bit more complex.

Anyone have experience with such a task? Side note, there might be a water well being drilled as well for an outside water source and there is a natural spring at bottom of property.
Pump and pressure tank at bottom of hill… need 1# pressure per 2’ rise, roughly.
 
I'm not sure how that functions if you don't start off with decent pressure to begin with

The well pump will be sized to provide enough pressure (& flow) to the pressure tank.
If that is inadequate, you can then install a booster pump to push it to the building.
All this has to be sized to accommodate the well capacity, your useage, elevation changes etc etc.

(We have done away with our pressure tanks in favor of newer pumps/controllers that don’t require them.)
 
In typical POA fashion, I don't have any answers, but I sure have more questions!

- Why bother with the water company if you are going to drill a well? I have a well with basically unlimited free water (other than the pump electricity) and would have zero interest in buying water from the man, regardless of if it were available.
- How long and tall is the hill from the rural source?
- What is the pressure at the source?
- Why can't you check the pressure at the top of the hill?

Lol, well first off being that treated water is already available at two ends of the property, so it's a bit easier to deal with. Being able to water a bit of yard and gardens with well water makes it cheap versus using rural water, so drilling a well makes some sense over the long run.

The property itself has about 170ft of elevation change from one end to the other based off of available info. The hill itself is about 400ft total above surrounding area (looking at VFR map).

We haven't checked with the 2 other houses on the top of the ridge yet as we haven't gotten that far into the process (don't know if they are on well water or rural water). No place to measure pressure at this point other than those houses which are a few hundreds yards down the road.
 
The well pump will be sized to provide enough pressure (& flow) to the pressure tank.
If that is inadequate, you can then install a booster pump to push it to the building.
All this has to be sized to accommodate the well capacity, your useage, elevation changes etc etc.

(We have done away with our pressure tanks in favor of newer pumps/controllers that don’t require them.)
With any luck there is adequate pressure at the top and we have no issues. The house and shop would be placed almost halfway down the 10 acre property which doesn't lose much elevation until that point. I'd guess that if we had to push water up the hill from the rural water tap, it would need to come up at least 80-100ft in elevation.

The water well at my current property uses a bladder-style pressure tank, but it is decades old and only runs the yard sprinklers (originally supplied the house before city water was brought in). Water well is only about 40'-50' deep in this area, so not much issue with sizing well pumps to provide adequate pressure.
 
Pump and pressure tank at bottom of hill… need 1# pressure per 2’ rise, roughly.

Hopefully we don't run into that issue, but it seems doable. Probably need a small insulated pump room if we had to do this option since it does get down into single-digit temps in the winter for a few weeks. Potential pad site would likely be between the 850-840 elevation lines.

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I have a pump in my basement that pulls the water in and provides pressure for inside the house. I assume downside is that if I lost the prime it would stop pulling but that has not happened. Yet.
I do not have to pull the water that far. Maybe 50 feet (horizontal) from a ground source (spring) that has zero pressure at the source.
The spring has minimal vertical difference from the pump. Within 10 feet vertically.
 
I have a pump in my basement that pulls the water in and provides pressure for inside the house. I assume downside is that if I lost the prime it would stop pulling but that has not happened. Yet.
I do not have to pull the water that far. Maybe 50 feet (horizontal) from a ground source (spring) that has zero pressure at the source.
The spring has minimal vertical difference from the pump. Within 10 feet vertically.

The positive side of this property is that we seem to have options, so that's encouraging. The view is pretty stellar as it's the tallest ridge in this area and has a radio antenna at the property to the North (so the neighbors are quiet on that side, lol). It's also less than 6 miles to a good airport, and less than 12 miles to another decent airport, both with 5K' runways.
 
For the metered run, you’ll may want 2” pipe up to the house before reducing it.
 
For the metered run, you’ll may want 2” pipe up to the house before reducing it.

What impact does that have? I understand larger pipe having increased flow (obviously flow would be limited in the house by capacity of 3/4" water lines), but wouldn't that be impacted the same if pressure dropped?
 
What impact does that have? I understand larger pipe having increased flow (obviously flow would be limited in the house by capacity of 3/4" water lines), but wouldn't that be impacted the same if pressure dropped?
A larger pipe won't change the static pressure, but will reduce the pressure drop caused by flow (think friction) when the water is flowing.
 
What impact does that have? I understand larger pipe having increased flow (obviously flow would be limited in the house by capacity of 3/4" water lines), but wouldn't that be impacted the same if pressure dropped?

Flow friction reduced, especially if you’ve got a long run from the rural tap to the house.
 
if I did the math right, 400 ft head = about 173 psi...so if the water at the bottom of the hill is 180 psi you would have about 7psi to work with not counting pipe losses....so yeah, something is doubtful cause I doubt they have that much pressure at the bottom of the hill.

regardless, you're told there's city water up there...so If you have any flow at all at the top of the hill, one idea is a throwback to old school technology....build a water tower on your roof like the ones you see on the roofs of highrise buildings in NY. Take the flow when you can get it, then you have a steady supply at a steady pressure to use.

To pump the water up, I recon the pump would pretty much have to be located at the bottom of the hill
 
Flow friction reduced, especially if you’ve got a long run from the rural tap to the house.

Gotcha. I was only considering static pressure, but that probably is a good idea as it would be probably a 250' run or so from the front of the lot (where I assume the water line runs). A little extra cost for materials, but in the grand scheme of things it's rounding error.

if I did the math right, 400 ft head = about 173 psi...so if the water at the bottom of the hill is 180 psi you would have about 7psi to work with not counting pipe losses....so yeah, something is doubtful cause I doubt they have that much pressure at the bottom of the hill.

regardless, you're told there's city water up there...so If you have any flow at all at the top of the hill, one idea is a throwback to old school technology....build a water tower on your roof like the ones you see on the roofs of highrise buildings in NY. Take the flow when you can get it, then you have a steady supply at a steady pressure to use.

To pump the water up, I recon the pump would pretty much have to be located at the bottom of the hill

Well, the 400' is mostly regional topography difference, the hillside itself seems to be about 200' from top to bottom but overall has about 400' above the surrounding 5 square miles or so. Either way I agree that it *should* be doable to get enough from the upper line. The thought of a reserve tank/pressure tank was what I originally considered, where the service line feeds a sizeable tank, so as long as you don't draw out more water than the tank supplies, the pressure would remain stable and would refill as needed.
 
They installed 2 inch line to our house. The meter is 3/4, as is the house so I don't see benefit of the 2 inch line. What I did see was water leaks from failed pipe joints. This is due to the more rigid 2 inch PVC as well as the significantly reduced psi rating of 2 inch PVC compared with 3/4 or 1 inch. All my leaks were at the bottom of the hill.
I would recommend 1inch line.

Our house is probably 300 feet above the meter.
20160909_130537.jpg
 
(We have done away with our pressure tanks in favor of newer pumps/controllers that don’t require them.)

Thanks for the tip. I think our pressure tank might be on its way out and I didn't know there were other viable solutions. Something else for me to look at.

What impact does that have? I understand larger pipe having increased flow (obviously flow would be limited in the house by capacity of 3/4" water lines), but wouldn't that be impacted the same if pressure dropped?

Others have answered and you seem to get it. But don't underestimate that friction. 250' is a pretty good distance and you don't want to have to redo those lines when it turns out the 3/4" isn't doing what you needed.
 
They installed 2 inch line to our house. The meter is 3/4, as is the house so I don't see benefit of the 2 inch line. What I did see was water leaks from failed pipe joints. This is due to the more rigid 2 inch PVC as well as the significantly reduced psi rating of 2 inch PVC compared with 3/4 or 1 inch. All my leaks were at the bottom of the hill.
I would recommend 1inch line.

Our house is probably 300 feet above the meter.
View attachment 116912

There’s NSF approved potable 2” poly in 500’ runs nowadays.
 
Thanks for the tip. I think our pressure tank might be on its way out and I didn't know there were other viable solutions. Something else for me to look at.



Others have answered and you seem to get it. But don't underestimate that friction. 250' is a pretty good distance and you don't want to have to redo those lines when it turns out the 3/4" isn't doing what you needed.

I replaced the pressure tank on our water well last summer when I came across a deal at a local outlet-type store. I also added a "cycle stop valve" for our application which is essentially a an adjustable pressure choke so that the pump stays running for longer periods of time instead of cycling on/off repeatedly during prolonged water draw. Since our well is only used for outdoor watering, it often runs for an hour straight, which would cycle the well pump frequently as the pressure tank dropped. Now the pump runs pretty much continuously with the pressure being kept below the cutoff pressure while the sprinklers run. May not make much difference, but since I was replacing the pressure tank that had the bladder ruptured I figured I may as well try it out.
 
May not make much difference, but since I was replacing the pressure tank that had the bladder ruptured I figured I may as well try it out.

Yeah, that's where I'm at also. I wouldn't replace it just for that advantage, but I think I need to replace it anyway, so appreciate the heads up. Things seem to have changed a lot since we put it in 25 years ago.
 
If you’re drilling a well, then this might not matter.

Pressure tanks these days are of the 1 gallon variety.

Pump motors are now controlled by variable frequency drives that flow the water you need to maintain the pressure you want.

People don’t realize that wells can be hundreds of feet deep with submersible pumps and a 1 inch supply line. Screw friction, size the pump adequately, use VFD, run the crap out of it for decades.
 
Yeah, almost everything in the Tulsa area is less than 150, most are under 75'. Water table is fairly high around here, which often makes basements hard to keep dry.
 
Last I checked pex pipe pressure rating appeared inadequate for that water column.
 
What kind of flow do you want? That will control what size line you will need. I usually like to limit velocities to < 5 fps on new design waterlines. At least long runs.
 
I have a pump in my basement that pulls the water in and provides pressure for inside the house. I assume downside is that if I lost the prime it would stop pulling but that has not happened. Yet.
I do not have to pull the water that far. Maybe 50 feet (horizontal) from a ground source (spring) that has zero pressure at the source.
The spring has minimal vertical difference from the pump. Within 10 feet vertically.

Back in the 80's and 90's I worked for a rural water system and that would go against our rules. Most of our water mains were put together with rubber seals that would pull in any water, around the water main, if suction was applied.

Better idea is to install a holding tank that is feed from the city water and then pumped by your pressure pump.
 
Water pressure is a function of pipe size / distance, elevation of the water tower and elevation of the property. Usually water towers are built on top of hills when able. Check the closest tower elevation, lot elevation and distance to the property.
 
Back in the 80's and 90's I worked for a rural water system and that would go against our rules. Most of our water mains were put together with rubber seals that would pull in any water, around the water main, if suction was applied.

Better idea is to install a holding tank that is feed from the city water and then pumped by your pressure pump.

Correct. Standard bell joints not only would allow groundwater to enter if suction is applied, but even if there is a positive pressure below the gasket's rating. For this reason, 20 psi is a standard minimum pressure for which, if not met, results in a flushing and disinfection of the main, by most utility standards.
 
Not quite enough information to answer your question. So, I’ll run through to scenario’s; 1) Hook up to city water; 2) Install your own well.


Common to both of them is the question of how much water do you need? For common residential use, 20 GPM at 45 PSI is more than ample. If you are going to do irrigation or livestock watering, that is likely not enough. You will need to decide this. Couple of other items: Do the houses at the top of the hill use city water or do they have their own well, hopefully they would be willing to tell you this. What are the specifications (size and pressure) of the city water line at the bottom of the hill? The local water utility should be able to tell you this, they probably could also tell you if running a line from the main to you house is feasible.


For running a line from the existing main up to the house. From what I can gather, the elevation difference is 150’ (860’-710’). So, you will need to overcome a head difference of 150’ which is roughly 65 PSI. Believe there was mention that the length of the line would be 250’. Line losses (friction) can be significant. Using the 20 GPM figure, the line loss for a 1” Schedule 40 PVC pipe is about 21 ft of water head per 100’ of run. For a 250’ run that would be about 23 PSI. For 2” piping the line loss drops to 0.8 ft per 100 feet of run or 1 PSI. All of these values change if you use a different material, but can be easily recalculated.


To deliver 20 GPM at 40 PSI to the house, using 2” line, the main would need to be capable of delivering that volume at a main line pressure of 65 (elevation head to be overcome) + 1.0 (line loss) + 40 (pressure at entrance to home) = 106 PSI. I doubt that the utility runs the line pressure that high, but it is possible depending on how they designed it. Suspect there would be no issue with the main to deliver the quantity of water you need, but the pressure issue may (likely) be a problem. A booster pump could be installed at the main line, it could be controlled via a standard bladder pressure tank/switch or by the newer variable speed pumps that sense pressure in the line and adjust accordingly. The location and sizing would need additional work as you don’t want to have a negative pressure on the main line. I did ignore line losses from valves/fittings/bends – they can be accounted for later if you go ahead with the design. I’m sure any competent plumber (with the assistance of the water utility) can help you design a system that works – it all does come back to how much water you need and how much you want to spend.


If there is public water at the top of the hill, that may be the way to go. Less elevation difference, and shorter line runs. Far simpler!


If you are going private well the most important factors are depth to water, drawdown volume and water quality. Did a lot of groundwater work in Tulsa (nice town BTW) a number of years ago, unfortunately it was all out on W.22nd. Street near Chandler Park. Was close to the river so groundwater was shallow, abundant – but – quality was highly variable, anywhere from sweet to pretty highly mineralized and occasionally briney. Groundwater quality can vary significantly upon depth and distance. A good place to start on that is a local well driller, they should be able to give you a ballpark idea of what to expect if you are going to put in your own well. As a backup the OK Department of Environmental quality could also give you some idea of what you might find if you drill a well, for a regulatory group, they were good to work with and pretty practical. It is nice to have “free” water with a well, there is that capital cost of installing the well and the associated delivery system. If the quality is good and the depth is reasonable, that may suit your purpose. Not that hard to wire the pump to a standby generator for those times the power is out and the wife wants to flush the toilet!


So, either way works, just a matter of complexity and cost.
 
All this said, you can't even begin to design your system without knowing your flow requirements. 1 gpm? 10 gpm? Can't specify a pump, can't size pipes, can't calculate frictional losses...
 
I may have missed this, do you know what the pressure is at the bottom of the hill ?
 
I may have missed this, do you know what the pressure is at the bottom of the hill ?
Went back out to the area to walk the land again and got to talk to the nearest house at the top of the hill (about 100 yds from corner of property) and they said everyone up there runs booster pumps, but the pressure is still pretty low. He (Ex military) joked that it was a bit more like the gravity showers he was used to in "the sand box", but his wife/daughters were less happy about it. He guessed it was probably 15-20psi but didn't know what the head pressure was for sure.

The home at the bottom of the hill adjoins the property) reported that he had close to 90psi at his house. That's encouraging, but still means you would have to pump it uphill 150ft from a lower tap.
 
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Water pressure is a function of pipe size / distance, elevation of the water tower and elevation of the property. Usually water towers are built on top of hills when able. Check the closest tower elevation, lot elevation and distance to the property.
We found the water tower on top of the same Ridge about 1/2 mile away, which is above the elevation where the house would be. However a neighbor at the top of the hill remarked that he knew a guy right next to the water tower and that he still had low water pressure. Supposedly there was talk about having a new pumping station put in to help rectify the situation but he didn't know the status of that project.
 
All this said, you can't even begin to design your system without knowing your flow requirements. 1 gpm? 10 gpm? Can't specify a pump, can't size pipes, can't calculate frictional losses...
Right, well I can't imagine there should be a really high consumption need. It's going to be a standard house with a shop, probably 2,400 sq ft of living space or less. No pools or major agriculture needs. Certainly nothing greater than a standard 3/4" line would be able to provide. I really just didn't know how to get adequate pressure when head pressure is low to begin with. We may gain a few psi from building the house 20'-30' lower in elevation than the neighbors, but that may just take it to "marginal".
 
So you do the same thing people with underproducing wells do: a storage tank and booster pump.
 
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