A borehole water survey answers one question: given everything that can be measured from the surface, where on this property is drilling most likely to succeed? It is the step that turns drilling from a guess into an informed decision.
It is worth being precise about what a survey does. It does not find water in the sense of proving that water is present at a given point. It identifies subsurface features associated with groundwater - fractures, weathered zones, contacts between rock types, saturated layers - and ranks positions on your property from most to least promising. That is genuinely valuable, and it is not the same as a guarantee.
Planning to drill? Have the site surveyed before you commit to a position.
Request a Water SurveyWhy Siting Matters More in Some Places Than Others
The value of a survey depends heavily on the geology under your property, and Cape Town has several very different settings.
In fractured hard rock - the Table Mountain Group sandstones and the granites - groundwater sits in fractures and joints rather than being spread evenly through the rock. Two positions fifty metres apart can produce entirely different results, because one intersects a water-bearing fracture zone and the other drills into solid rock. This is where siting earns its keep.
In the Cape Flats sand aquifer, water occupies the pore spaces of a sandy formation that is relatively continuous. Position matters less for whether you find water, though it still matters for depth to water, for avoiding contamination sources, and for deciding whether a borehole or a wellpoint is the appropriate solution.
In the Malmesbury shales, the picture sits between the two - weathered zones and fracturing both play a part, and siting helps identify the more productive structures.
Survey Methods
A survey normally combines more than one method, because each measures a different property of the subsurface and each has blind spots. Agreement between two independent methods is far more convincing than a strong reading from one.
| Method | What it measures | Where it is most useful |
|---|---|---|
| Electrical resistivity | How readily the ground conducts electricity, which varies with moisture, clay content and rock type | Mapping weathered zones, depth to bedrock, saturated layers and the contrast between formations. A workhorse method across most Cape Town geology. |
| Electromagnetic (EM) profiling | Ground conductivity, measured by traversing lines across the site | Quickly covering a property to identify anomalies worth investigating in more detail. Often used first to narrow the search area. |
| Magnetic surveying | Variations in the magnetic field caused by geological structure | Locating dykes and intrusive contacts, which frequently act as either water-bearing structures or barriers to flow. |
| Desktop hydrogeological review | Existing records - geological mapping, groundwater data and nearby borehole results | Establishing realistic expectations for depth, yield and water quality in your area before anyone sets foot on site. |
On water divining. Traditional divining or dowsing is still widely offered in South Africa, and some practitioners have a good local record. It is not, however, a measurement-based method, and its results cannot be independently reviewed or reproduced the way geophysical data can. If you want a defensible basis for deciding where to spend money on drilling, use instrument-based geophysics - and be wary of anyone offering certainty from any method.
What a Survey Involves on Site
- 1Desktop review of the geology and any available groundwater information for the area, before the site visit.
- 2Walkover and site assessment - property boundaries, structures, slope, drainage, vegetation and rig access.
- 3Locating existing services and potential contamination sources: sewer lines, septic tanks, soakaways, French drains, fuel storage and stormwater.
- 4Establishing survey lines or traverses across the accessible parts of the property.
- 5Taking measurements along those lines with the chosen geophysical instruments.
- 6Interpreting the data against the known geology, rather than reading the instrument output in isolation.
- 7Identifying and ranking drilling targets, with an expected depth range for each.
- 8Reporting, including the recommended position, alternatives, and an honest statement of the uncertainty involved.
What You Should Get From a Survey
- A marked, pegged position for drilling, with at least one alternative
- The reasoning behind the recommendation, in language you can follow
- An expected depth range and what is anticipated at depth
- The methods used and the raw survey data or profiles
- Confirmation that the position clears existing services and structures
- Any contamination risks identified nearby and what they mean for the borehole design
- A frank assessment of confidence - including if the site is unpromising
That last point matters. A survey that concludes your property has poor prospects has saved you the cost of drilling, which is a useful outcome even though it is not the one you wanted. A surveyor who always finds an excellent target on every property is not giving you information.
Get a survey and a drilling quote priced together so you know the full picture before starting.
Request a Survey QuoteThe Limits of a Water Survey
Being clear about this protects you from disappointment and from anyone selling certainty:
- A survey improves the odds. It does not guarantee water. Geophysics measures indirect indicators, not water itself.
- It cannot reliably predict yield. A promising anomaly may deliver a strong flow, a modest one, or very little. Only yield testing after drilling establishes what a borehole will actually produce.
- It tells you nothing about water quality. Chemistry and microbiology are established by laboratory analysis of an actual sample, not by surface measurement.
- Access constrains the survey. Buildings, paving, boundary walls and dense planting limit where lines can be run, and on a small urban plot the genuinely surveyable area may be modest.
- Interference affects readings. Buried metal, reinforced concrete, electrical cabling and fencing can distort geophysical data, particularly in built-up areas.
- Depth resolution decreases with depth. Detail near surface is better than detail well below it.
Is a Survey Worth the Cost?
Set the cost of a survey against the cost of drilling. Drilling is charged per metre, and a dry or poor hole in hard rock represents a substantial spend with nothing to show for it. On fractured hard-rock sites, where the difference between a good and a poor position can be decisive, a survey is generally money well spent.
On a small property in a sandy area with a shallow, laterally continuous aquifer and very limited space to drill anyway, the balance shifts - there may be only one viable position, in which case surveying it changes nothing about where you drill. An honest surveyor will tell you when that is the case.
Where you should always insist on a proper site assessment, survey or not, is on locating services and contamination sources. Drilling into a sewer line or siting a borehole downgradient of a septic soakaway causes problems that are expensive and sometimes impossible to undo.
After the Survey
The survey report feeds directly into the drilling scope: the position, the anticipated depth range and the expected formation all shape how borehole drilling is planned and priced. Share the report with your drilling contractor rather than just the pegged position, because the reasoning behind it is useful to them.
Related Borehole Services
A survey is only worth doing if the drilling that follows is done properly, so it is worth reading how Borehole Drilling Cape Town works before you book one - the survey report feeds directly into how the hole is planned, priced and constructed.
What a Borehole Water Survey Costs
Siting is a fixed-sum scope rather than a per-metre one. Set it against the cost of drilling: on a hard-rock site, a survey typically costs less than ten metres of drilling, and it is the cheapest thing you can do to improve the odds before committing to a per-metre rate.
| Item | Indicative range | What moves it |
|---|---|---|
| Desktop hydrogeological review | R1,500 – R4,000 | Existing geological mapping and nearby borehole records. Sometimes bundled into the survey fee. |
| Geophysical survey, domestic property | R5,000 – R12,000 | Property size, how many methods are used, and how much of the plot is actually accessible to survey. |
| Geophysical survey, farm or large site | R12,000 – R25,000+ | Hectares to be covered, number of traverses, and how many targets need ranking. |
| Written report with ranked targets | Usually included | Confirm it is. You want the data and reasoning, not just a peg in the ground. |
These are indicative ranges, not a quotation. They are compiled from published South African supplier and contractor pricing to give you a starting point for budgeting. They are not our rate card, and no figure here is a commitment.
Treat them as a broad guide only. Published borehole pricing in South Africa varies enormously - different 2026 guides quote per-metre drilling rates for the same province that differ by a factor of three - because depth, geology, access, specification, distance and fuel costs all move the number. Depth in particular is not known until the hole is finished. Figures generally exclude VAT unless noted, and change over time. Only an itemised written quote against your actual site means anything.
Borehole Water Survey FAQs
Can a water survey guarantee that we will find water?
No. A survey identifies the positions on your property most likely to intersect groundwater and rules out the least promising ones, which meaningfully improves the odds. It measures indirect indicators from the surface - resistivity, conductivity, magnetic variation - rather than detecting water itself.
Treat any guarantee of water with caution, whatever method it comes from. What a good survey gives you is a defensible, reasoned basis for where to drill, plus an honest assessment of how confident that recommendation is.
How does a geophysical borehole survey actually work?
The instruments measure how the ground responds to electrical, electromagnetic or magnetic signals along survey lines across your property. Different subsurface materials respond differently - saturated fractured rock, dry solid rock, clay and weathered material each produce distinct signatures.
Those readings are then interpreted against what is known about the local geology to identify features associated with groundwater, such as fracture zones, weathered horizons or geological contacts. The interpretation matters as much as the measurement.
How long does a borehole water survey take?
Fieldwork on a typical domestic property is usually completed within a few hours, depending on the size of the site, how much of it is accessible and how many methods are being used. Larger properties and farms take longer because there is more ground to cover.
The report follows afterwards, since the data has to be processed and interpreted rather than read straight off the instrument.
Can a survey tell me how much water the borehole will produce?
Not reliably. A survey can indicate that a position looks promising and suggest a depth range worth targeting, but it cannot quantify what the borehole will deliver. A strong-looking anomaly may produce a good flow or a disappointing one.
Yield is established only after drilling, by test pumping the completed borehole and measuring how the water level behaves under a controlled abstraction rate.
Will a survey tell me whether the water is drinkable?
No - that is a completely separate question. Geophysical surveying measures physical properties of the ground and says nothing about chemistry or microbiology.
Water quality is determined by taking an actual sample from the completed borehole and having it analysed by a laboratory. See borehole water testing for what that involves and which parameters matter.
Do I need a survey if my neighbour has a good borehole?
A neighbour's borehole is useful information - it tells you the aquifer is productive in your area and gives you a realistic idea of depth and likely water quality. In a sandy, laterally continuous aquifer that may be a fairly good guide to what you can expect.
In fractured hard rock it is a much weaker guide, because yield depends on intersecting specific fractures, and those do not extend uniformly across property boundaries. That is exactly the setting where surveying is most worthwhile.
What if the survey says my property is unsuitable?
Then it has done its job and saved you a considerable amount of money. A survey that identifies poor prospects is a useful result, even though it is not the one you were hoping for.
Depending on the setting, there may be alternatives worth discussing - a different position, a different target depth, or in sandy areas with a shallow water table, a wellpoint rather than a borehole. Be wary of any surveyor who never delivers an unfavourable finding.
Should the same company do the survey and the drilling?
Both arrangements are common and each has a fair argument. Using one company keeps responsibility in one place and means the surveyor's reasoning passes directly to the driller. Using an independent surveyor removes any incentive to recommend drilling where prospects are marginal.
What matters more than the arrangement is that you receive the actual survey data and reasoning rather than just a peg in the ground, and that the recommendation comes with an honest statement of confidence.
DECIDE WHERE TO DRILL FIRST.
A survey narrows the odds before you commit to a drilling rate per metre.
Request a Water SurveyRequest a Borehole Water Survey
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