Need help with the principle of siphoning : LUSENET : TimeBomb 2000 (Y2000) Preparation Forum : One Thread

Hi, folks, I am trying to siphon water out of my well, in order to fill a tank from which to pump water with a solar "surface" pump, which I'm finding, is quite a bit less expensive than a submersible, and also easier to service.

I'm fortunate to have a very high static level (currently about eleven feet, and actually flows out the top all winter). I have dropped a twenty-one foot long 3/4 inch pipe down the well, then 180 feet of 3/4 inch pipe running down the hillside below the well, which drops the pipe down to the elevation equalling 18 feet below the top of the well.

No problem starting the siphon; the problem is that the flow diminishes from about 2 1/2 gpm to less than 1/4 gpm over about four hours. Once, it stopped altogether, although I think that was caused by my not gluing one fitting together (in order to facilitate pulling the siphon back out when I'm done--I think it enabled a little air to get in and break the siphon)

I'm going to continue playing with this, maybe adding more pipe (on both ends). But I wonder if anyone else has ever had experience with this, and if there is any way that the siphon could fail without either drawing down the well below the siphon pipe, or having an air leak.

Thanks a lot.


-- Al K. Lloyd (, September 22, 1999


Water always has a little air dissolved in it, and under suction that air tends to slowly come back out. Like a soda fizzes, but much slower.

At the top of your siphon curve, that air builds up to make a pocket. That pocket sorta blocks the flow. Try this - put a T joint right at the top of the curve - the highest point in the pipe. The water flows from one side of the T to the other, and turn it so the leg of the T is vertical above the pipe. Put a two-foot pipe in the T leg, and cap it. That give the air someplace to go without blocking the pipe. The more pipe you have up there, the more air it can contain before the siphon slows down.

-- bw (home@puget.sound), September 22, 1999.

Thanks, BW; I'll try that tomorrow; I am afraid I don't understand why the air wouldn't be sucked through along with the water. Maybe the water is travelling too slowly, and the air keeps going up to the top?

It makes sense that there might be some air in the water. I also know that the reason you can't siphon from the theoretical maximum depth is because, when you start create a powerful vacuum, the water starts vaporizing, and this water vapor acts like any other gas, and breakes the siphon. But I'm not deep enough, I don't think, to have this problem, at only twenty-one feet of lift.

I'll keep you posted; there may be other folks who could use this info. It would be real nice to be able to have a RELIABLE water supply without having to install a pump.


-- Al K. Lloyd (, September 22, 1999.

Yeah, the water is going too slow to move the air along.

By the way - when you start the siphon, make sure that T leg is full of water, not air. That is, turn it so the leg is *down*, get the siphon going, then turn it up. Needs a little flexibility in the pipe, to do that.

-- bw (home@puget.sound), September 22, 1999.

Thanks again, BW; I think I'll put a valve at end of the riser pipe, then let the water blow out through it, then shut the valve after I'm sure the pipe is full of water.


-- Al K. Lloyd (, September 22, 1999.

Considered the possibility that the WELL has to re-fill from the surrounding rock/soil? Unless it's Artesian, I don't know of a well that you can't over drive errr over drain by trying to do what you are discussing.


-- Chuck, a night driver (, September 25, 1999.

Al, I sure hope you plan to purify that water ... filtration through a really good filter. Any water so near the surface is definitely going to contain some serious pollutants.

-- Shelia (, September 26, 1999.

Chuck and Sheila,

I appreciate your concern, but fear not--the water is as pure as you could ever get. The SOURCE of the water is not shallow; it is merely fairly near the surface because it's under pressure.

Chuck, this will not affect the well in the way you suggest; I finally perfected the siphon, and it is providing 3 3/4 gallons per minute, and has held steady at this rate for a four hour test. I now have shut off the flow, but it can be restarted easily, merely by uncapping the end of the pipe. Incidentally, this flow rate is a small fraction of the well capacity, which is 35 gallons per minute, and is only one third the flow that my electric pump provides (approximately twelve gpm)

BW, I didn't need to put the TEE in the line, as you suggested. By extending my siphon line another 200 feet down the hill, I increased the flow rate enough that the velocity in the pipe seems to be fast enough that the bubbles can't fill up the pipe at the top.

Anyone else who has a well with a static level within twenty-five or so feet of the surface, I highly recommend this for an emergency clean water source, which is available without electricity. But you need to perfect the method early, before the power goes out.


-- Al K. Lloyd (, September 26, 1999.

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