Jack, I did that project a few years ago, but don't have the time to write everything out. But, I did find the following post on a newsgroup last year that is really excellent.
A sand point shallow well is mostly just a pipe driven into the ground. Water flows into it from the surrounding wet sand and a suction pump pulls it up to the surface. The water originates as rain or snow then filters down through the sand replenishing the water table.
Obtaining water in this way is can be simple, inexpensive (about $300 or $400 for many years of service) and very satisfying - if a lot of things go right. There are, however, many uncontrollable factors so it isn't surprising that water witching has survived to recent times.
Before deciding to install this type of well you will want to contact your local government about what if any permits you will need. This little pipe probably isn't going to break through into the region's main aquifer but ground water contamination is very difficult to remedy and some level of caution is understandable - the regulations aren't always enforced very well.
Next, try to determine whether the water table at your site is likely to be within 22 feet or so of the surface. This is necessary for the pump to be able to pull up a reasonable volume of water. Contact your local hardware stores and plumbing supply outlets. If they stock shallow well equipment there is probably some demand. Smaller outfits are definitely more helpful. You may even find someone who knows something about it. Your local equipment rental place may have some tools and information. Listen closely for the words "rock" and "clay."
Old settlements were established where water was readily available. Windmills and hand pumps operate with an underground piston mechanism which is able to push water up much farther than a shallow well pump can suck it. So don't rely on this as an infallible indication. Water tables change too.
Look over the sand points and pumps and pipe fittings and electrical wire and supplies and so on to get and idea of the scale of such a project. You won't need a lot of this stuff until you are sure you have a well. (We have a 3/4 h.p. pump which operates on 220 volts.)
The sand (a/k/a drive) points I am familiar with are 1 1/4" and 1 1/2" in diameter, 3' and 4' long and contain 60 mesh or 80 mesh screens. For more water volume, more expense and more difficulty choose a point of 1 1/2" diameter, 4' long with 60 mesh screens. For cheaper, easier but less water choose 1 1/4", 3 feet long and 80 mesh. In my situations the smaller size with 60 mesh screens have worked out ok.
Get three galvanized drive couplings. They are thicker than regular ones and will stand up to the pounding better. They also fit a little tighter sometimes.
Have the store cut and thread three 7' lengths of galvanized water pipe of the same diameter as the point.
Obtain a point pounder (driver). Typically, it will be a three foot long, weighted section of 3" pipe with handles welded to the sides. They aren't real expensive but nobody has ever worn one out either so borrowing or renting one should be possible. If you are working alone, look for one that weighs 40lbs. or so. Otherwise, you might try a heavier one. A 70lb. driver is quite a handful but it really makes things happen.
You also need a drive cap. This is a heavy cap with a small hole drilled in the top that screws onto the top of the pipe and protects it from the impact of the pounder. Be sure the pounder fits over it. Don't try using a drive coupling. The top of the pipe will be damaged and you will have to either cut and re thread it in the field or jack it out of the ground as far as the next lower coupling.
Other things you will need are 2oz. of pipe thread compound, two 18" pipe wrenches, a #2 shovel, a 6' folding ladder. Handy to have are a pipe vise, 2' ladder, small spirit level, string and a pitcher pump.
Choose the best location. You will eventually need to run electricity to it etc. Be sure you have room overhead to operate the pounder. Consider hiring a douser?
Read any instructions which may have come with the point. Assemble the point, a drive coupling and a section of pipe applying pipe compound to the threads. Make sure it is screwed together very tightly because you won't be able to get to it again. I use a pipe vise. Some people try to weld these connections but it isn't necessary and usually doesn't work. Screw the drive cap on and snug it up with the wrenches.
Dig a 12" wide hole as deep as is convenient. Digging is easier than pounding - everything is easier than pounding. Set the ladder up next to the hole and move the tip of the point to the hole. Slide the driver over the cap end and pick the driver and pipe up together allowing the point to slide into the hole. Climb the ladder to a convenient level carrying the driver and pipe with you. You are going to repeatedly lift the driver then slam it down onto the top of the pipe so get arranged accordingly. The whole neighborhood is going to hear it and you're going to look real good if it works.
Before you start pounding adjust the pipe so it is vertical. A helper can eye it up with the edges of two buildings or check for plumb with a level. Adjust this after every two slams until you can't correct it anymore. It get can get away from you very quickly and none of the consequences are pleasant.
Start pounding. Progress slows down quickly. I count twenty then rest for about 30 seconds. Do this five times then re tighten the coupling and cap - use both wrenches whenever possible so you don't rotate the point. Repeat ten or fifteen times and your first piece of pipe will probably be in the ground. Put on another length and do it again. Keep in mind that this is "good for the figure."
Pound the point down far enough so you can sit on the ground to tighten the next length on and so you don't have to climb the ladder as high to get the pounder back over the top. Remove the cap and tighten it onto the next piece, spread pipe compound on the threads and assemble with a coupling.
Tighten using both wrenches in opposite directions. When tightening the couplings don't rotate the point any more than is necessary as it will destroy the earth's grip on it and you won't be able to tighten the lower couplings using a wrench on the top. (Loose couplings allow air into the pipe and you will pump bubbles instead of water.)
Start looking for water after the second piece of pipe is well along. (It is possible to go right through a layer of water - sitting over a clay layer.) Tie something to a string. It should be smooth, small and sort of heavy - I don't like using lead sinkers because they might get wedged in the point and stay there (yuk). Most objects I have tried get stuck somehow and are difficult to bring back up. I made an electronic sensor once and it worked great but I took it apart to make something else. Resist any temptation to put a tape measure down the pipe.
Measure the string so you only let down a length equal to the distance to the tip of the point. It is difficult to feel when the object hits the bottom. Some of the string may be wet when you pull it up. Six feet of water would be great but less might be ok. The well at home began with damp sand - no water - and I couldn't go any deeper - and it was the third location in two days - and it is 50 yards to a lake.
Some experts run water from a hose into the pipe to backwash the screens. I do it because I have seen them do it. If there is little or no water in the point let it sit for a few hours then check it. Fine grained silt can prevent the ground water from flowing into the point. Even with no water in the point connect and prime the pump and try pumping it. In some cases a small pitcher pump works better than an electric one.
If all the pipe is in and its dry then you're probably done with that particular well. I don't know any more tricks. You could drive a little more pipe maybe, or wait a few days - put a cap on it. You can spend the time thinking about how you are going to pull it up - hope it isn't bent - or leave most of it down - re driving bent pipe is not easy.
Or maybe you hit a spring of crystal clear fresh cold water.
Wells need to be pumped off which means that you run them for several hours at full flow - it may not look like much right away. This removes fine sand from inside the pipe and screens and from the area around the point. As the fine sand is pumped out the water flows to the point better and the well works better. A slow well may keep improving for two or three years before leveling off. Eventually the screens may lime up and the flow will diminish. An old plumber I worked for used to fire his .38 down the pipe which, I imagine, blew the screens out - literally.
Now you might start thinking about a pump, check valve, union, pressure tank, nipples, electric wire, switch box, receptacle, spade or trencher and shelter. If you are going to run your pump on 220 volts you might spend a little more money and pull four conductor wire so you can have a neutral and a 110 volt outlet at the site. I didn't and I'm stuck with using my ground wire. It wouldn't be difficult to spend a week at this. Remember to always cap the well rather than leave the pipe open. Keep in mind too that the impeller housing will freeze and crack pretty easily. Disconnect the pump each fall, drain it out and take it in the house if you can.
As I mentioned above, one thing which might go wrong is that there just isn't any water in your pipe. You could try again fifty feet away and find it and maybe not. Jack your point out and try a second place. The underground is a complex three dimensional structure. In excavations we see it in limited two dimensional cross sections. Water soaks in everywhere at the surface but it may then flow away from your site, either sideways or down.
Another thing which might be a problem is rock. You can bash through small rocks. Your point may deflect sideways off others. Some pipes go down quite curvy because of this and require a lot of pounding. Other times you are just stopped dead. When this happens, jack your point out and move a couple of feet to one side. My neighbor spent just about every weekend for more than a year trying to locate a spot where he could get through the rocks below us. Finally he dug a hole twelve feet deep with shoring on the sides and pried an opening in the rocks to pound his point through - god I laughed - he was determined.
Another problem is silt. A couple of years ago I worked on a point for a guy who had advertised and sold his house with a working sand point. When he realized it wasn't working he tried pulling it but it broke off. Then he hired me to pound a new one.
It went down easy with water at 12'. After another 10' feet I tried to pump it off. Within fifteen seconds the pipe and pump were plugged solid with fine doe colored sand - like the kind on very fine sand paper. He then told me that he had had the same problem when he put the original point down. Back then he went out after supper every evening for a couple of weeks and pumped it with a hand pump for about an hour. He thought this must have created a cavity around the point. Following that he ran a high volume electric pump for several years. (To clear the pipe of silt push a running hose down it and the silt bubbles out - don't let it get stuck. Take the pump apart.)
Another problem is clay. Sometimes you can pound your way through a thin layer or it isn't too sticky. Other times not. A clay layer is often good because it prevents ground water from seeping away deeper.
I was fixing a well one time and an old timer told me that under this end of this particular town there was a three foot thick layer of blue clay. A week earlier I had needed a well machine to pull the point and it came out with a bend in it. I thought that maybe with a big pounder and some luck I would be able to put the new point down the same hole. I used a 70lb. driver with a big tripod and a pulley. At twelve feet the driver was bouncing and the pipe wasn't moving and that was it. Luckily there was plenty of shallow water for the hand pump and it tested fine so that's where it ended.
Some places rent out a machine with a gas engine that rotates the pipe and a special point which shoots a stream of water fed by a hose. The assembly slides on rails and the point pretty much just sinks into the ground. If you have to get through clay this thing might be just the ticket. It is quite another story when it hits rocks however - you should have seen my neighbor. He was running this thing and had even put on a second length of pipe and was laid back in his lawn chair watching it work, smokin' a butt and suckin' a beer when it started bouncing then locked up in the rocks. Whoa. It was a year before he had water.