Borehole Yield Testing

A yield test, also called test pumping, shows how much water a borehole can supply sustainably. SANS 10299-4 sets out how it is done, and the result guides the pump size, the pumping rate and what you can safely take.

Last reviewed 2 October 2026. Costs are market indications from public price pages, not quotes.

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Why Yield Testing Matters

Shows a sustainable pumping rate, so you avoid pumping more than the borehole can supply

Informs pump selection and the depth the pump is set at

Useful evidence if you ever register a use or apply for a licence. Draft regulations reported in February 2026 would require yield test results before abstraction, but they are not law

Gives baseline data for long-term monitoring of your water level

Gives the yield and hydraulic properties of the borehole and its aquifer. It does not measure how fast the aquifer recharges

Costs much less than a pump system, so testing before you buy the pump is cheap insurance

Types of Yield Tests

SANS 10299-4:2003 covers the test-pumping of water boreholes. A consultancy that tests boreholes says DWS will only authorise groundwater use if the correct yield testing method is used. We have not read the standard text, which is paywalled, and the durations below come from two test-pumping consultancies.

Blow Yield Estimate

The driller estimates flow at each water strike using compressed air. It is indicative only and not a basis for sizing a pump or for deciding how much you can take.

During drillingAccuracy: Indicative

Step Drawdown Test

The pumping rate is raised in steps, for example one third, two thirds, equal to and one and a half times the expected yield, while the drawdown is measured. It assesses how productive the borehole is and sets the rate for the constant-rate test.

4 to 6 steps of 1 hour eachAccuracy: High

Constant Discharge Test

A pump runs at a constant rate while water levels are recorded. Under SANS 10299-4 practice it typically runs 24 to 72 hours, and longer where large abstraction is planned. The standard allows 12 to 100 hours or more depending on the planned use of the water. This is the test used to establish a sustainable yield.

Typically 24 to 72 hoursAccuracy: High

Recovery Test

The water level is monitored after pumping stops, until it has recovered to within 5% of the total drawdown, three readings in succession are identical, or a time equal to the pumping time has passed.

After pumping stopsAccuracy: High

What a Yield Test Costs

A basic domestic yield test (SANS 10299) is quoted at about R1,500 to R5,000.
One Gauteng price guide quotes a constant-rate test at about R3,000 to R7,500 in Johannesburg and Pretoria.
A pump system is quoted at about R15,000 to R45,000, which is why testing before you choose the pump is worth it.

Longer tests and deeper holes cost more, and quotes vary by region. Ask what the quote covers, including the report.

Understanding Your Yield Results

These are the yield classes DWS uses on its hydrogeological maps, in litres per second (L/s) with the hourly equivalent. The figure that matters is the sustainable yield from a constant-rate test, not a blow yield. For scale, a household using about 30 kL a month uses about 1,000 L a day, which is about 42 L an hour if pumped around the clock. 10,000 L/hr is about 2.8 L/s, which is mid-range on these classes.

Class	Flow Rate	Per Hour	What It Means
Low Yield	0.1 to 0.5 L/s	360 to 1,800 L/hr	A household can be supplied with a storage tank and a pump sized to the tested yield, but check how the level recovers
Moderate Yield	0.5 to 2.0 L/s	1,800 to 7,200 L/hr	Often enough for a household and garden. Confirm with a constant-rate test
Good Yield	2.0 to 5.0 L/s	7,200 to 18,000 L/hr	Can support larger demand such as irrigation or a guest house, subject to the test and your authorisation
High Yield	More than 5.0 L/s	More than 18,000 L/hr	What you may take still depends on your use and authorisation, not on the yield

Yield Is Not the Same as What You May Take

Yield is what the borehole can supply. What you may take depends on the volume you actually abstract and what for. Under the General Authorisation you must register with DWS if you take more than 10 cubic metres a day on average over a year, and you need a licence if you want more than the General Authorisation allows for your property. A high yield does not by itself trigger a licence. A test cannot create water either: if the yield is low you design around it with storage and a smaller pump, or look elsewhere. See our permits and registration guide.

Get Your Borehole Tested

Send one request and borehole testing companies in your area can quote. BoreholeZA lists companies from public information and has not inspected them, so ask what the test covers and who signs the report.

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Sources

Geoss: borehole yield test requirements (SANS 10299-4 step, constant discharge and recovery procedure; DWS position)
Umvoto: borehole test pumping, what you need to know (test duration under SANS 10299-4:2003; purpose of the step test)
Borehole Water Association: SANS 10299 parts (Part 4 is test-pumping of water boreholes)
DWS Johannesburg 1:500 000 hydrogeological map brochure (DWS yield classes in L/s)
Government Gazette 40243, Notice 538 (2 September 2016): Revised General Authorisation (10 m3 a day registration trigger and 40,000 m3 cap)
IOL/Mercury, 4 February 2026: proposed borehole drilling regulations (draft regulations, not law)
Waterpoint SA: borehole drilling in Gauteng, cost, yield and suburb guide (constant-rate test price in Johannesburg and Pretoria)
Cape Town borehole drilling costs 2026: regional price guide (Waterpoint SA) (basic domestic yield test price)
Borehole prices 2026 (Borehole Hub) (yield test and pump system prices)