How to Dig an Economic Deep Well

Note that this discussion is limited only to my case, this is not applicable in all places and all soil profile. In our place, the soil profile is, from top, 10 ft clay, 5 ft sand, 5 ft gravel then bedrock. The water table is 8 ft below the ground surface. You may not follow exactly what I did; at least you have now an idea of a hand dug well.

I’ve been busy this summer for our small home improvements. I tiled the floor with a ceramic tile and after it I dug a deep well. Water is one of the problems in our place. The developer is trying too many alternatives but of no avail. I am living in a hill; our place is called Regina Hills Subdivision. The problem of water is not only in our subdivision but a city-wide problem. So I created this move, dug a water well for my self.

The Cost of Digging

I used the word dig because we literally dig the well, drilling is not in our list. When I open a conversation to some workers that I plan to dig a well, many workers come into my house and offer their service. They are at different rate and of different level of knowledge and experience in well digging. The following are the rates of digging in our place.

500 pesos per foot (P500/ft)
There are three contractors offer me their service with this rate. It includes the digging, pipe fittings, and pump installation. These workers are no doubt knowledgeable of the job, and they can do work without my instructions. They have the full set of digging tools.

300 pesos per foot (P300/ft)
Most contractors have this rate; in fact some contractors in 500 pesos per foot are willing to drop to this rate just to get the job. It also includes the digging, pipe fittings, and pump installation but they are not as knowledgeable as the 500 pesos per foot contactors and their equipments are not that complete.

250 pesos per foot (P250/ft)
This is the rate of almost all diggers in our place.

None of the above rate I choose. I offered to one laborer 3,000 pesos (P3,000) for the first 20 feet and I will increase the payment if he can go deeper than 20 ft. He agreed and we start digging. Of course, he needs all my instructions; all he knows is to dig.

The Original Plan

Below is the section view of the deep well.

Materials

Pulley – the pulley I used cost 100 pesos (P100) only. You may use one-toner pulley but it is expensive and too strong to lift 1 bucket of soil.

Rope – the rope is 4 pesos per meter (P4/meter), I bought 10 m long.

Tripod – You can use steel tube or timber post. I use two bamboos at P35 each, cut it into appropriate length and assemble it into a tripod.

Bucket – I use old water (jug) container for bucket cut it into two and use rope for the handle.

4” Pipe Casing – Most prefer to use the Eslon Blue pipe but it cost P1200 in its 20 ft length. I used 2 sanitary pipes (the orange in color); it is only P150 in its 10 ft length and P12 coupling to connect the two. The lower 10 ft of the casing must be drilled all around at 1 ft vertical interval to let water inter into the casing. The next vertical line of holes must not be in the same horizontal line so that the pipe will not weaken. See Figure B below. You may use a hot rod to create the hole or a drilling machine. To avoid spending some electricity in drilling, I used hack saw and create a long wound on the pipe. The idea is to let the water enter into the casing, no matter what is the shape of your hole. Just make sure your pipe will not weaken.

Blue drum (barrel) – I installed 200 liter food grade blue drum (used as container of food syrup). You can also use drums that contain industrial soap like the soap for washing the cola bottles. Avoid drums that were used in petroleum and chemical products.

You may use concrete culvert in replacement of the blue drum, it is stronger than the plastic drum. If you use concrete culvert, avoid those that are dark in color. Its dark color is due to used oil in the culvert mold. Culvert that is made first in the morning will took this oil; it will contaminate your water for a long time if you happen to use this culvert. I use blue drum for economic reason. The 24” culvert costs P800 each while the blue drum is only P650 each. To drop (install) the culvert is another cost (at P250 each) while the drum cost nothing in its installation. Drill also some holes to the sides of the first three drums so that water can enter into it.

Suction Pipes – The size (diameter) of your suction pipe depends on the inlet of your pump. Most hand pump has an inlet of 1-1/4” and most motor pump (motor pump for household purposes) has an inlet of 1”. I drop two suction pipes, one for hand pump and the other for motor pump. Avoid dropping a single suction pipe for both hand pump and motor pump. Do NOT use GI pipe, it will rust and not economical. I used Eslon Blue, rust is not a problem for this plastic pipe and it’s economical in terms of material and installation.

Foot valve with strainer – Foot valve with strainer is a must at the bottom end of your suction pipe. This will help retain the water in the pipe and avoid the intrusion of some stone and sand.

The Digging

You start to need a motor pump when the well starts to collect ground water or if you reach below the water table. Manually removing the water with a bucket will exhaust your laborer and their focus will not be the digging. To go below faster, pump the water with a motor pump. The risk here is the dirt that will enter into your pump. But it can be minimize by not letting the foot valve with strainer touch the bottom of well. Water up to the knee is manageable in further digging. Use flexible hose for this purpose; do not use the final suction pipe. Always clean the hose when the pump slows its performance. Clay may accumulate to the sides of the hose. Much better if the well can reach bedrock, the quality of water at that depth is good and avoid stopping at a clay layer. You can stop the digging if you reach sand stratum or bedrock.

Blue Drum (Barrel) Installation

Before you drop the blue drum, fill at least 1 foot thick of 2” gravel to the bottom of the well, make it level and you can drop the blue drum. Make sure that the drums are open both ends as shown in the plan. Make the holes at the ends enough for a person to pass through it. For the uppermost drum, the hole at the upper end is just enough for the 4” diameter casing pipe to pass. Tie the drum with a tie wire and using the rope and pulley, carefully drop it to the center of the well with assistance of the laborer at the bottom, once the drum is placed pour the ¾” gravel to the sides of the drum (make sure not to pour the gravel inside the drum). The laborer must be at the top of the drum to accomplish this task. The ¾” gravel will act as strainer of dirt from entering the drum. Once the gravel is level with the first drum, drop the second drum directly above the first and again pour ¾” gravel outside the drum. Repeat this process to the uppermost drum.

Once the gravel is labeled with the uppermost drum, drop the 4” pipe casing into the hole then pour approximately 1 foot thick gravel to the top of the drum. Add clay to the top, this is to avoid surface water to contaminate the ground water, the thicker the better. Make sure that you will not overstress the drum, do not fill on top of it more than 6 ft thick.

Reinforced Concrete Cover

Reinforced concrete cover is necessary to avoid load from the surface (weight of person water in a bucket, backfill, etc) to be carried by the drum. You can use 8 mm deformed steel for reinforcement, 10 mm is much better. The ring of this cover must lie on the natural ground, not on your backfill; this is to ensure that its purpose is being served appropriately.

With all these things ready, you can now start installing your motor pump and/or hand pump. Enjoy your water.