leodrilup.gif (7091 bytes)

Finishing the Well

Before you reach the bottom of your new well you will want to have all the things you will need to finish the well nearby, so here is a list of things needed to finish a well.


Permanent Casing

The permanent casing is a pipe that will be left in the ground to provide access to the aquifer from the surface.

The least expensive pipe in most countries is plastic PVC pipe. The least expensive casing to use is the thin-walled 4-inch PVC that is usually used for drains in houses. It comes in lengths of ten and twenty feet. This type of casing is very inexpensive, easy to carry, and easy to cut and shape.

Other types of pipe, like thick-walled PVC and galvanized steel pipes will work, although they can be more costly. In colder climates where the ground freezes in winter, steel casing is required.

Casing can be made locally by using hollowed tree lengths or baked clay pipe formed in short sections and stacked inside the hole. Some drillers have used hollowed bamboo as well. But the wood and bamboo casings will rot quickly if it is in the water at the bottom of the hole. If you would prefer to use wood or bamboo, you might consider using plastic or steel in the aquifer and then line the rest of the well with the other material.

You will need enough casing to line the entire length of your well.

The Screen

The screen is a piece of casing that has holes which will allow the water from the aquifer to enter the casing. The screen’s holes are small so that the water can enter the casing but the soil cannot.

Manufactured screens can be purchased that have thousands of tiny slots cut into them. They are usually the same size as the casing, four inches wide and ten feet long.

You can make your own screen by cutting a piece of casing with a thin-bladed hack saw so that there are small slots every 1/2 inch along the casing. Cut the slots about two inches long and place them on all sides of the casing so that the casing does not become weaker on one side only.

Or you can punch small holes in the casing with a small nail. You will want to have thousands of holes in the screen so that it will not become plugged quickly.

Making the screen is a good job for somebody younger, older, or otherwise unable to help with the drilling.

Fittings and Glue

The thin-walled PVC usually comes with a flared top that acts as a coupler to attach the next pipe. If not, you will have to purchase couplers or dip the thin-walled casing in hot oil to soften it enough to shape it to fit over the next pipe.

You will need a four-inch cap or plug to close off the bottom of the screen.

The PVC pipe and fittings are glued together with a special cement for PVC. When you buy the cement you will also need to get some primer that is used to clean the pipe and prepare it to be glued.


The top of the well will have a concrete platform. If you use the cement with the right mixture of rocks and sand you will only need one bag for a small platform. You may need several bags for a larger platform.

Clay and Sand

The sand is used to help screen the water at the aquifer and the clay is used to seal the top of the well.

When the screen is installed at the bottom of the well there will be room inside the hole on all sides. To keep soils away from the screen, sand is poured in to fill up the hole around the screen.

The sand can come from the local stream, but it must be sorted so that only the larger pieces, or the coarse sands, are used. The smaller pieces of sand would only clog the screen, but the larger pieces can act like a filter to help the screen keep the smaller soils away from the well.

The sand can be sorted in two ways. Using the screen listed in chapter 3, which is made from wire mosquito screen, you can wash sand in the stream so that the smaller sands fall through the screen and leave behind the larger pieces. Or you can dry the sand in the sun and then dry sift the sand through the screen. By sifting the sand in the screen the smaller sands will fall through.

You will need sand for both packing around the screen and the cement for the platform, so have plenty ready. Figure on having at least 12 wheelbarrow loads.

The clay will be used to seal the well hole so that water cannot flow down into the well. Look for clay that has little or no sand in it. You will need at least three wheelbarrow loads of clay.


Installing the casing/screen

As soon as you know you have drilled into the aquifer you will want to have all the casing materials and sands ready to install. The water filled earth is the most likely to cave-in so you will have to act fast. If you are not using a casing as you drill you will want to install the permanent casing the minute you finish drilling through the aquifer.

Try to drill as far as you can into the aquifer, at least ten feet below the water level. When you stop making progress, or when you have drilled 10 to 20 feet into the aquifer, bail out the hole one last time and prepare to install the casing.

Since your hole may be six inches wide at the bottom (even wider at the top) and your casing only four inches wide, you will want to tie equal sized small blocks of wood to the sides of your casing to help center it in the hole. Support the bottom of the screen with a rope so that the weight of the casing does not pull against the newly glued joints. A loop of light weight rope or vine that goes down one side of the casing, under the screen, and up the other side works fine.

If you are using PVC casing that comes in ten foot sections, you may want to glue pairs together beforehand so that you can work faster with twenty foot sections.

Lower the screen into the well hole and hold it tight so that a foot of casing sticks out of the hole. If you have casing clamps that will fit the casing, use these for extra security. Glue the second piece in place and let it dry for a few minutes. Lower the casing again, keeping the weight on the rope and not the casing joints, until once again only a foot sticks out of the well hole. Repeat the above process until you have installed the length of casing you want.

After the casing is inside the hole, take some time to make sure that the casing is straight and that it is centered inside the hole. If you have a bubble-type level, measure to make sure that the casing is standing straight and not leaning in one direction or another. Otherwise you can use a weight on a string (sometimes called a plumb bob) to check to see if the casing is straight.

When you are satisfied that things are straight, slowly pour the first few buckets of sorted sand down the hole to hold the bottom of the casing in place. Then pull out the rope that you used to lower the casing. Pour in more sand until you know that the screen has been covered by at least five feet. You can use the depth gauge to figure out how much of the hole has been filled.

Sometimes the sand may clog and not fill the hole evenly. Use a long, thin stick or a narrow weight on a rope to pack the sand properly. By pouring slowly and evenly, the risk of clogging is lessened.

Stop every ten feet to check that the casing is still straight.

After the screen has been covered with the sorted sands, pour in a few buckets of clay mixed with a little water so that it is slightly runny. This will provide a seal for the screen.

Then backfill the well hole with thick mud made from the soil taken from the hole. Turning the soil into mud will make it easier for the soil to travel to the bottom of the well hole and to pack itself tightly around the casing. Fill the well hole until the mud reaches a point ten feet from the surface. Stop filling and let the mud settle for a day.

After the mud in the hole has dried the level will probably have dropped a foot or two. Pack dirt into the hole until the unfilled portion is only ten feet deep.

The next eight feet (up to two feet from the surface) is then filled with more clay mixture. Mix the clay so that it is thick enough to stand in a pile if shaped by hand, but moist enough to not have any hard lumps larger than one inch across. After it dries, this layer of solid clay will protect the well from surface water running down into well alongside the casing.

When the clay is dry it is time to install the concrete platform.


Making the concrete platform

The platform provides a sturdy and weatherproof cover for the well and prevents spoiled water from running into the well. Working with concrete is an art in itself, so don’t be discouraged if your first platform isn’t perfect. Even though it can be more expensive, plan to use extra cement to build your first platforms bigger and thicker than you think you’ll need. It is better to be safe than sorry.

After you have installed the well casing and re-filled the hole with sands, mud, and clay, you should have the top two feet of the well hole left to be filled. After waiting a day for the mud to settle and another day for the clay, the surface of the ground around the well should have dried.

The least expensive way to shape cement is to dig out a form in the earth. By digging a circle six feet across and six inches deep, and then piling and shaping a wall made from another four inches of dirt around the circle, you will have made a form for a ten inch thick platform. Make the walls of the piled dirt as thick as possible to hold the weight of the concrete.

If you have plenty of material at your disposal, or if you need to build a platform on sandy soil, you can use wood planks, bamboo, steel (strips of zinc roofing works well), or stones to make the concrete forms.

The form design is entirely up to you, but here are some good ideas to follow:

Make the platform as wide as possible — six feet across is about as small as you should go — and as thick as possible (ten inches at least), with at least two feet of the well hole being filled with concrete.

Use as much steel reinforcement as possible. Concrete itself is very likely to crack apart unless it has some steel to hold it together.

Build the platform so that the outside edges are lower than the middle around the pump. This will make the spilled water flow away from the well and prevent spoilage.

Imbed the bolts which will hold down the pump in the cement so that they will not move. You might need to make a special form to hold the bolts so that they fit exactly with the pump.

Form a trough that will carry water from the pump spout away from the well.

If the pump is short (like the Consallen) build a small pedestal for the pump so that those who will use it (think women and children) can pump without bending over.

<< Back to index

  Back to Index

Wellspring Africa's
Hand Powered Percussion Drill

Copyright @ 1986-2012
by Cliff Missen and Wellspring Africa