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Digging a Puit!

Posted: Mon Jun 09, 2008 6:56 am
by Juddy in the Charente
My neighbours all have a well and, with the (hopefully!) oncoming heat of summer, I would love to have one as well to help keep down the water bill.

Any ideas on where to start?

Posted: Mon Jun 09, 2008 7:09 am
by Clara
If you are hoping to tap into underground water, I reckon you would need a permit (it is France afterall!). It can damage the water table if you do something without proper guidance.

Posted: Mon Jun 09, 2008 8:05 am
by The Riff-Raff Element
Remarkably, it being France and all, usually you don't need a permit. There are exceptions, but I'll come to those.

Unless you have water at 6m or less (or are very determined), digging a well by hand is probably not a practical proposition. You should find in the 'phone book under "forages" a list of your local bore-hole drilling specialists. It is they who will be able to tell you whether you are in one of the few areas were you need permission to drill.

They will either carry out a geological survey (basic seismic) or will employ a deviner to locate water sources. We had deviner. I don't know how it works, but it does. If I can't believe the evidence of my own senses what should I believe?

A couple of points to bear in mind:

- the well will not be cheap: we paid just less than €1000 four years ago for 35m including the casing (the pipes that line the well);
- the price of the pump will depend on the depth, but at 35m we paid a further €450 for a down-hole electric pump that we fitted ourselves. The limit for surface pumps (which are cheaper) is about 12m. There is a good reason for this to do with mechanics that my wife did try to explain to me (chemical engineer - a kind of plumber) but I forget it now;
- you could of course use a windmill / sucker-rod assembly and run it from any passing zyphers. It depends how you want to use the water;
- If you connect the supply to your own house for domestic (rather than garden, pool or agricultural use) your commune has the right to charge you a flat fee for not using town's water. Bizarre, I know, but there you are. Our's wants €70 per year.

Posted: Wed Jun 11, 2008 7:59 am
by theabsinthefairy
If you try your mairie they will have the water plans for your commune and will tell you if you have a source accessible on your land before you get any further complications into actually digging for water. Even if you have a source its location may prevent you from actually sinking a well, take a look at your neighbours and try to picture an aerial view and you will see where potentially your source may be.

If yours is an old village house, ask the neighbours if there was ever a well in the first place, it may have been filled in, and if there was not ever a well there is probably a very good reason, as it is unusual for an old village house not to have a water supply. (please bear in mind I have no idea what type of property you have!)

Water diviners in France are excellent and there is usually someone local probably related to one of your neighbours who can find water for the price of a couple of glasses of pastis!

Be aware that rural areas of France have variable water tables dependent on the weather - and the rains of the last two years have raised the water tables, but a long hot year may dry up your well if not deep enough.

Currently our well has a water level you can touch and the source is merrily trickling down the garden creating a little stream which would normally be carried underground - the ducks are loving it!

Posted: Fri Jun 13, 2008 3:48 am
by possum
The Riff-Raff Element wrote: The limit for surface pumps (which are cheaper) is about 12m. There is a good reason for this to do with mechanics that my wife did try to explain to me (chemical engineer - a kind of plumber) but I forget it now;
Not entirely true, ours is suppose to be able to pump from 30m down to 30m up, it doesn't need to as the water table is only 8m down, but that is its specification.

Posted: Fri Jun 13, 2008 7:31 am
by The Riff-Raff Element
possum wrote:
The Riff-Raff Element wrote: The limit for surface pumps (which are cheaper) is about 12m. There is a good reason for this to do with mechanics that my wife did try to explain to me (chemical engineer - a kind of plumber) but I forget it now;
Not entirely true, ours is suppose to be able to pump from 30m down to 30m up, it doesn't need to as the water table is only 8m down, but that is its specification.
Is it a centrifugal pump or some kind of positive displacement arrangement?

Posted: Fri Jun 13, 2008 7:58 am
by possum
The Riff-Raff Element wrote:
possum wrote:
The Riff-Raff Element wrote: The limit for surface pumps (which are cheaper) is about 12m. There is a good reason for this to do with mechanics that my wife did try to explain to me (chemical engineer - a kind of plumber) but I forget it now;
Not entirely true, ours is suppose to be able to pump from 30m down to 30m up, it doesn't need to as the water table is only 8m down, but that is its specification.
Is it a centrifugal pump or some kind of positive displacement arrangement?
no flamin idea tbh it is man electtric thing and it pumps, does that help?

Posted: Fri Jun 13, 2008 10:08 am
by The Riff-Raff Element
possum wrote:
The Riff-Raff Element wrote:
possum wrote: Not entirely true, ours is suppose to be able to pump from 30m down to 30m up, it doesn't need to as the water table is only 8m down, but that is its specification.
Is it a centrifugal pump or some kind of positive displacement arrangement?
no flamin idea tbh it is man electtric thing and it pumps, does that help?
:mrgreen: No, not really.

The main difference, it seems, is that centrigual pumps are good for big flows but only work for deep sources if they (or, at least the pump impeller arrangement - the motor can stay up on top) are lowered down the hole and displacement pumps will work down at pretty much any depth but at comparitvely low flows.

Windmill type pumps are displacement pumps as are those nodding-donkey things that are used on oil wells. Most irrigation pumps are centrifugal.

Posted: Fri Jun 13, 2008 9:18 pm
by possum
thinking about it (and hopefully not putting too many typos in), it is the sort of pump that uses water it has already pumped, to pump up more water, I don't quite understand how it works, but it means it has two pipes going down into the bore.

Posted: Fri Jun 13, 2008 11:21 pm
by andyt
Sounds like you have an ejector pump(its all to do with air venturies ,etc), as for you Juddy,there are numerous possibilities. No surface mounted pump will draw water from a depth greater than 27ft...it's the law of barometric physics.However a surface mounted rod pump will draw water from a vastly greater depth(working on the same principals as a bycycle pump,believe it or not).If your water table is no more than approx. 6M down,then you could enquire about a "wellpoint", which,basically,is a miniature borehole,using a surface mount pump instead of a submersible(a much cheaper option). Around our neck of the woods,the average depth to a good supply is 30M(we are in chalk),but there is no limit to pump type(submersible).Basically, the greater the demand,the bigger the pump.