A family, a school, a clinic, a farm, a factory, a municipality: all call a drilling contractor with the same question — will we have water? — and expect an answer the trade can only give afterwards. The subsoil can be guessed at through study, is discovered during drilling, is measured in the pumping test and is judged by the analysis. The drilling contractor that presents its work in that order, with what each stage can and cannot say, is the one that deserves to be paid. Stage by stage, here is what it does.
Before drilling: the study and the permits
The first question is not where to drill but whether to drill: is there a network nearby, a neighbouring borehole whose yield is known, a spring? Then comes the study: geological and hydrogeological maps where they exist, existing boreholes in the area, sometimes a geophysical survey to locate favourable zones, a site visit to check access for the rig, distances to sources of pollution — latrines, septic pits, dumps, livestock — and the intended use of the water. The study does not guarantee water; it improves the odds and reduces the risk of drilling dry.
In many countries, drilling requires a permit or a declaration to the water authority, and sometimes a specific licence for major uses. The contractor knows these rules, informs the customer, and does not open a site “in the meantime”: an undeclared borehole can be closed, and the water it gives has no legal existence.
Drilling: the rig, the ground, the method
Rotary or percussion rig, air or mud depending on the ground, diameter suited to the planned casing and the intended pump: the choice of method depends on the expected geology, and the contractor justifies it. During drilling, the driller in charge records what is being crossed — nature of the strata, depth of water strikes, rate of advance — in a drilling log that will become the borehole section, an essential document for understanding what one has and for any future maintenance. A borehole without a section is a hole about which no one knows anything once the rig has left.
The site has its risks: heavy machinery, rods and tools in motion, compressor or mud pump under pressure, noise, dust, work under the sun. Helmets, footwear, gloves, an exclusion zone for onlookers — often numerous around a rig —, secured loads and emergency-stop instructions are not traded against a deadline.
Casing, grouting, protection
The hole is lined: plain casing in the zones to be sealed off, screen opposite the water-bearing levels, gravel pack, and grouting of the head to stop surface water — loaded with whatever the soil contains — from running down the casing to the aquifer. That wellhead protection, and the slab covering it, decide the quality of the water in the years to come; WHO insists, in its guidelines for drinking-water quality, on protecting abstraction points against contamination. A borehole well drilled but poorly protected supplies water that deteriorates with every rainy season.
Development and the pumping test: measuring what one has
Water gushes out, the customer rejoices, and the work is not finished. Development — intensive pumping, air, sometimes brushing — cleans the borehole of mud and fines until the water comes clear; the pumping test, run for a sufficient duration with regular measurements of flow and level, says what the borehole can give sustainably — not what it gives for ten minutes. It is that operating yield, and not the instantaneous flow announced on site, that must be used to choose the pump.
The contractor hands over the test results in writing, with the conditions under which it was carried out, and says clearly that a yield measured in the rainy season may fall in the dry season, and that a newly drilled neighbouring borehole may reduce it.
Water analysis: what the driller does not decide
Clear water is not drinkable water. Potability is judged on analyses — bacteriological, physico-chemical — done by a laboratory, according to national standards based on WHO guidelines. The drilling contractor samples by the rules, has the analyses done, hands over the results and explains what they mean; it does not declare water drinkable itself, and does not promise potability before the results. Some parameters — iron, manganese, fluoride, nitrates, arsenic in some areas — require treatment or rule out drinking use, and it is better to know before installing the pump.
Equipment: pump, energy, network
Once the borehole is characterised, the contractor installs or has installed the pump — hand pump, submersible electric, solar — sized from the pumping test and the delivery head, with its power supply, its tank, its secured wellhead and a meter where possible. An oversized pump empties the borehole and damages it; an undersized pump disappoints. Energy is part of the sizing: a solar pump gives its flow while the sun shines and stores it in a tank, a pump on an unstable grid is protected against surges, a hand pump needs arms and spare parts. The contractor hands over a complete file: borehole section, equipment, pumping test, analyses, operating and maintenance instructions, and what to do if the yield drops or the water changes.
Neighbouring trades: dowser, well-digger, plumber, laboratory
The drilling contractor is not the dowser: it relies on geology and, where it can, on an instrumented survey, and it says what these methods cannot predict. Nor is it the well-digger, who digs large-diameter, shallow wells by hand — another trade, with its own risks of collapse and asphyxiation —, nor the plumber who connects the network after the tank, nor the laboratory that judges the water, nor the authority that issues the permit. It works with each of them, and it is by naming their roles on its estimate that it avoids carrying responsibilities that are not its own.
The estimate: drilling costs, finding is not guaranteed
The estimate separates the study, rig mobilisation, drilling per metre — at a price that may vary with the ground —, casing and screens, grouting and wellhead, development, pumping test, analyses, pumping equipment, and what is not included: the tank, the network, the electrics, the permits. It says what happens if the borehole is dry or insufficient — a reality of the trade: the customer pays for the drilling carried out, the contractor does not bill the equipment of a borehole that does not produce, and a second borehole is the subject of a new estimate. These rules are written down before starting.
What the contractor guarantees: conformity with good practice, the section, wellhead protection, the test and analyses handed over. What it does not guarantee: the yield before the test, potability before the analysis, and the life of an aquifer that others also exploit.
In the African context
The borehole is, across much of the continent, the most widespread access to water outside urban networks: the WHO/UNICEF Joint Monitoring Programme for water and sanitation measures, country by country, the share of households, schools and health facilities that depend on water points such as boreholes fitted with pumps. That place gives the trade a public-health responsibility: a borehole poorly protected, poorly sited relative to latrines or poorly developed supplies water to hundreds of people — and sometimes a disease.
The second variable is the aquifer itself. FAO highlights the growing pressure on freshwater resources; in many fast-growing African cities, private boreholes multiply without coordination, and the yield of each depends on that of its neighbours. The contractor that explains to its customer that their yield may fall, that respects permits and that advises against an additional borehole where the aquifer is already stressed exercises a prudence the market does not always reward.
One last point, maintenance and abandonment: hand pumps broken for lack of parts, boreholes abandoned without being sealed — open paths to the aquifer —, casings torn out for the metal. The contractor that trains the users’ committee or the manager in maintenance, keeps a stock of parts for the pumps it installs and properly seals a borehole it abandons makes what it drilled last.
What the end-of-borehole report must contain
The geological and technical section of the borehole, with depths, casings, screens and grouting. The drilling log. The results of development and of the pumping test, with dates, durations, flows and levels. The laboratory analyses and their interpretation. The description of the equipment installed. Operating and maintenance instructions. The permits obtained.
A customer who holds that report knows what they own and will be able to have it maintained by anyone. A customer who has only an invoice and running water has a hole in the ground — until the day the water stops and no one knows why.