# Hypothetical question about pumping water **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 31, 2026, 8:28pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726 "2026-08-31T20:28:46Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [September 1, 2026, 12:29am UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/21 "2026-09-01T00:29:02Z")
> [@eschereal](#): > > Perhaps adding a cooling loop at the top of the pipe could improve throughput a little. As in post #4, the equipment is called a “cold trap”. You can Google that term and see many for sale for applications very different than this one. The actual physical limitation in your scenario would be heat flow into the surface region of the water. That surface will cool quickly, as every molecule of water you pull away costs you one chunk of vaporization heat. That heat has to come from somewhere: convection is your best bet, limited by practical choices on the ground. If you pump too fast, you’ll freeze the surface. So, you’d need to throttle the pump to draw just below the rate where it would overshoot the input heat. This rate will vary with the environmental conditions. If you use a fat pipe and if (mostly) convection can get tens of watts of heat flowing continuously to the surface, and you don’t accidentally freeze the surface, you could maybe get a gallon of water every three days when the lake is warm. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [September 1, 2026, 12:51am UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/22 "2026-09-01T00:51:53Z")
> [@LSLGuy](#): > > Seems obvious to me from the highly contrived setup. With various practical alternative solutions carefully blocked off. I concluded from that setup that this is almost certainly a thought experiment, not an IRL dilemma. > > The word “Hypothetical” in the title is another tell. Well, i did ask the OP to clarify that point. Maybe i wasn’t explicit enough: > [@puzzlegal](#): > > So this is not actually a question about getting water to the house (something to make it possible would presumably be included in the easement language) this is about the pump? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 1, 2026, 12:31pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/23 "2026-09-01T12:31:14Z")
Yes. You asked the key question and right up front, but they never answered you. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [September 1, 2026, 12:36pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/24 "2026-09-01T12:36:51Z")
And the next two posts, by @ricepad and @Pasta pretty much answered the hypothetical. Which, i suppose, is why the thread turned to “how to get water to the house” instead of the hypothetical question. 🤷‍♀️ So, turning to that: > [@ricepad](#): > > > [@Dewey\_Finn](#): > > > > Doesn’t the easement establish a right to the water? > > Nope. While it’s illegal in most jurisdictions in the US to sell property without a right of access, it’s perfectly legal to sell property without a known water supply. Although, if there’s an easement to run a line at all, it’s a really badly written easement that doesn’t let you put a pump at the bottom, where it belongs. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 1, 2026, 12:39pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/25 "2026-09-01T12:39:40Z")
If the actual question was about the suction height limit, I really wish that @eschereal had just asked that rather than framing the ridiculous scenario. ---
**Author:** ![ASL\_v2.0](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asl_v2.0/32/3525_2.png) [@ASL\_v2.0](https://boards.straightdope.com/u/ASL_v2.0)\ **Post date:** [September 1, 2026, 1:17pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/26 "2026-09-01T13:17:38Z")
Clearly, what’s needed, is a heated pipe. Heated to the point of boiling the water at its base. Then you put a condenser system at the top. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [September 3, 2026, 1:23pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/27 "2026-09-03T13:23:39Z")
You could use a jet pump with an ejector at the bottom of two pipes. In this system your pump, which is at your house, forces water down one pipe, where it goes through the ejector at high speed and picks up additional water, then returns up the other pipe. The ejector is tiny, like the size of the screen you’d have down there anyway. If you only have permission for one pipe, you would run the other pipe inside it, so a pipe within a pipe. See “Shallow well pumps” here: > **[Injector | Well pumps](https://en.wikipedia.org/wiki/Injector#Well_pumps)** > > Jet pumps are commonly used to extract water from water wells. The main pump, often a centrifugal pump, is powered and installed at ground level. Its discharge is split, with the greater part of the flow leaving the system, while a portion of the flow is returned to the jet pump installed below ground in the well. This recirculated part of the pumped fluid is used to power the jet. At the jet pump, the high-energy, low-mass returned flow drives more fluid from the well, becoming a low-energy, hig... ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 3, 2026, 1:45pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/28 "2026-09-03T13:45:23Z")
The short answer is: Yes. When one is evacuating A/C systems, the vacuum pump gets saturated with water vapor. This is exactly what would happen in your scenario. Of course, you would have to worry about the water in the pipe freezing, which is also what happens during A/C pump down. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 6, 2026, 5:10pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/29 "2026-09-06T17:10:08Z")
> [@eschereal](#): > > My question is this: your suction pump is still pulling stuff out of the pipe – water vapor and air; would it be possible/feasible to feed the pump output into a large condenser in the attic such that it would allow you to actually get water to your house? The practical short answer to your question is no. It would be easier to use a dehumidifier unit on the ambient air if you want to go this route. > [@eschereal](#): > > You have built a house on a hill with a really good view. Now for the water problem. > > The water available to your house is a large lake, 50 feet below the hill. You do not own any of the hillside, but there is an easement that allows you to run a pipe down to the lake. That, and only that. > This is an obvious problem, because physics tells you that you cannot pump water more than about 30 feet up, and you are forbidden from putting any equipment on the hillside to make up the difference. > > (…For the sake of argument, the easement restrictions and the considerable traffic of various kinds on the hillside make it impractical to put a small screw turbine down in the pipe to assist in raising the water.) As you state, a pump at the surface cannot suck water up more than 32 feet. That’s because a pump at the surface draws a vacuum, and the ambient air pressure pushes the water up the pipe. At one atmosphere of pressure (14.7 psia), that corresponds to a theoretical maximum of 33.96 feet. Because you won’t be able to draw a complete vacuum and due to friction losses, the practical limit is somewhere between 20-25 feet. So the answer is to put the pump at the bottom. By the stated description of the problem, if you can put a pipe down to the lake, you can put a small submersible pump down inside the pipe as well. (Yes, I get that you have posed a hypothetical situation that does not allow this, but this really doesn’t make any sense.) But whether you can do this or not, you don’t want to. Lake water without treatment is not suitable as potable water. (Due to animals, fish, runoff, etc.) It is far better to drill a well instead and intercept the naturally filtered groundwater. And what is a drilled well? A vertical pipe with a submersible pump at the bottom. 😉 ---
**Author:** ![sboy](https://avatars.discourse-cdn.com/v4/letter/s/ac8455/32.png) [@sboy](https://boards.straightdope.com/u/sboy)\ **Post date:** [September 10, 2026, 1:29pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/30 "2026-09-10T13:29:48Z")
I thought that i recalled a fountain in Switzerland that pumped water 450 feet into the air. This seems to exceed the 30 feet we are talking about. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [September 10, 2026, 2:06pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/31 "2026-09-10T14:06:57Z")
You can push water up more than 30 feet, but you can’t pull it up that far, because you are really just creating a vacuum, and air pressure pushes it up. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 10, 2026, 2:10pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/32 "2026-09-10T14:10:46Z")
> [@sboy](#): > > I thought that i recalled a fountain in Switzerland that pumped water 450 feet into the air. This seems to exceed the 30 feet we are talking about. The difference is where you put the pump. In the scenario the OP posed, you have a pipe going downhill to a water body with a pump at the _top_ of the pipe. The pump draws a vacuum and the surrounding air pressure pushes the fluid up the pipe. This is exactly how a drinking straw works. If Superman had a 35 foot straw and tried to suck water up, he would be limited to ~30 feet. Or if you drilled a well and put at pump at the top, you would have the same limitation. The limit is on how high a pump can suck water. But if you put the pump at the bottom, there is no limitation. But the pump is no longer sucking the fluid up the pipe. Instead, with the pump at the bottom (like a submersible pump), the pump pushes the water up. This can be done for hundreds of feet up the pipe, or into the air like the fountain in Switzerland. ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [September 10, 2026, 3:30pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/33 "2026-09-10T15:30:45Z")
> [@mixdenny](#): > > just put an Archimedes screw in the pipe. Or a chain bucket brigade. I think this is the only way. But does that count as pumping? The screw needs a straight shot from point A to point B. The bucket brigade is a bit more flexible. Is there any limit to the diameter of the pipe? Could you put pipes and pumps inside a bigger pipe so you can suck up water from the inlet in the pond, then push the water up the rest of the way with another pump? ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 10, 2026, 4:07pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/34 "2026-09-10T16:07:15Z")
> [@jjakucyk](#): > > > [@mixdenny](#): > > > > just put an Archimedes screw in the pipe. Or a chain bucket brigade. > > I think this is the only way. But does that count as pumping? The screw needs a straight shot from point A to point B. The bucket brigade is a bit more flexible. An Archimedes screw would work, and it also counts as pumping. Note that you have to maintain the seal between the screw and the pipe casing or it won’t work. And if the seal is too tight, you can’t physically turn the screw. But there are much better methods than this, such as a small-diameter submersible pump. > [@jjakucyk](#): > > Is there any limit to the diameter of the pipe? Could you put pipes and pumps inside a bigger pipe so you can suck up water from the inlet in the pond, then push the water up the rest of the way with another pump? You don’t need multiple pumps. A single submersible pump within the pipe that sits beneath the surface of the water will work. Or if you don’t want the pump to be submerged, place a self-priming pump less than 30 feet above the surface of the water so it can lift the water that distance, and then have it push the water up the remaining distance. (The closer to the surface and less it has to lift, the better it will work. But if the pump is submerged below the surface, it will work even better.) This is exactly how a well pump works. I have one in the front yard of my house. My residential well consists of 6-inch diameter perforated steel pipe that is drilled down about 400 feet into the bedrock, with a small submersible pump inside that is placed about 300 feet down or so. The pump sits below the groundwater level, sucks water in, and then pushes water up the well (via a 1-1/4” discharge PVC discharge pipe that runs up the well). The suction and discharge all happen within the body of the pump. (It’s a [centrifugal pump](https://en.wikipedia.org/wiki/Centrifugal_pump#).) ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [September 11, 2026, 7:14am UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/35 "2026-09-11T07:14:36Z")
> [@robby](#): > > But if you put the pump at the bottom, there is no limitation. But the pump is no longer sucking the fluid up the pipe. Instead, with the pump at the bottom (like a submersible pump), the pump pushes the water up. This can be done for hundreds of feet up the pipe, or into the air like the fountain in Switzerland. > **[Edmonston Pumping Plant](https://en.wikipedia.org/wiki/Edmonston_Pumping_Plant)** > > A. D. Edmonston Pumping Plant is a pumping station near the south end of the California Aqueduct, which is the principal feature of the California State Water Project. It lifts water 1,926 feet (587 m) to cross the Tehachapi Mountains, after which it splits into the west and east branches of the California Aqueduct to serve Southern California. It is the most powerful water-lifting system in the world, other than pumped-storage hydroelectricity stations. There are 14 4-stage 80,000 horsepower ... There are pumps in California that lift the water almost 2000 feet. The pumps are at the bottom, lifting the water. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [September 11, 2026, 2:11pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/36 "2026-09-11T14:11:16Z")
> [@Ancient\_Nerd](#): > > > [@robby](#): > > > > But if you put the pump at the bottom, there is no limitation. But the pump is no longer sucking the fluid up the pipe. Instead, with the pump at the bottom (like a submersible pump), the pump pushes the water up. This can be done for hundreds of feet up the pipe, or into the air like the fountain in Switzerland. > > [Edmonston Pumping Plant - Wikipedia](https://en.wikipedia.org/wiki/Edmonston_Pumping_Plant) > > There are pumps in California that lift the water almost 2000 feet. The pumps are at the bottom, lifting the water. Which is pretty impressive. The discharge pressure of the pump and exerted on the pipe at the bottom is a minimum of 833 psig just to overcome the water head (i.e. the pressure of the water at the bottom). To actually get the water to flow requires even more discharge pressure. Typical water main fittings are only rated for 250 psig or 350 psig. This must be very robust equipment to withstand that kind of water pressure. P.S. I didn’t mean to imply that lift pumps are limited to pumping water only “hundreds of feet” up. The actual limitation is mainly an engineering and/or materials constraint, not a physical one. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [September 11, 2026, 2:44pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/37 "2026-09-11T14:44:46Z")
> [@Beckdawrek](#): > > Water is not a right, it’s a privilege. I don’t doubt your veracity on this, but there is something about this that has always struck me as being inhumane. > [@Beckdawrek](#): > > A buyer needs to know these things in advance. That was my very first thought. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 11, 2026, 2:50pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/38 "2026-09-11T14:50:39Z")
No, they are wrong to say that water is not a right. The [United Nations](https://www.unwater.org/water-facts/human-rights-water-and-sanitation) recognizes access to water and sanitation as a basic human right. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [September 11, 2026, 2:52pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/39 "2026-09-11T14:52:34Z")
So, that we’ve covered the practical answers, can we start in on the impractical ones? The fundamental problem is the ambient pressure is too low. To fix that, we cover the pond with a strong material and pressurize it. Kind of like the [Metrodome](https://en.wikipedia.org/wiki/Hubert_H._Humphrey_Metrodome). With enough pressure, we can pump the water from the top of the pipe. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 11, 2026, 2:56pm UTC](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726/40 "2026-09-11T14:56:33Z")
In the context though - water delivered to your home is not a right. If I build a house in an isolated area I would be on thin ice, if only there was water for ice to form, demanding water service as a right. [Previous page](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726.md?page=1) [Next page](https://boards.straightdope.com/t/hypothetical-question-about-pumping-water/1032726.md?page=3)