Is Borehole Water Safe to Drink?
Last reviewed . Limits are from SANS 241-1:2015 (see the note on editions below). Test prices are indicative, from published prices.
Not automatically. Test it before you drink it.
Borehole water can be excellent, but nothing treats or tests a private borehole unless you arrange it. Clear, odourless, good-tasting water can still carry E. coli, nitrate, fluoride or arsenic. The only way to know is a laboratory test against SANS 241, repeated on a schedule.
- Until you have a result, give babies and young children another source.
- If a limit is exceeded, find out whether a cause on your property can be fixed, then choose treatment to match, and retest the treated water.
- Boiling kills germs. It does not remove nitrate or toxic chemicals.
What borehole water is, and why it varies
Borehole water is groundwater pumped from the cracks in rock or the pores of sand below your property. A water provider treats and monitors a municipal supply. For your own borehole, treatment and testing fall to you.
The DWS sampling guide notes that the quality of an aquifer is typically reasonably constant over time, but that local land use may have a significant impact on groundwater quality. So two boreholes in the same street can differ, and the result you got five years ago says little about today. New to boreholes? Start with the borehole guide for beginners.
What makes borehole water unsafe in South Africa
Two kinds of cause. The first comes from the surface: pit latrines, septic tanks, kraals, sewage works, fertiliser, landfills and a leaking wellhead. The second comes from the rock: natural fluoride, natural nitrate in dry country, and acidic water. The regional notes below are published findings, not a map of your plot.
Gauteng
The Department of Water and Sanitation (DWS) brochure for the Johannesburg map sheet says dolomitic aquifers are especially vulnerable. It says high nitrate has entered groundwater from pit latrines in informal settlements, cattle kraals, sewage plant effluent and heavy fertiliser use, and that mining's contribution to poorer water quality is substantial. Start with nitrate and E. coli. Near mines, ask the lab to add sulphate, metals and TDS.
Northern Cape, North West and Free State
A CSIR paper at the 2000 WISA conference found high nitrate in groundwater mainly in a band running from the Northern Cape through North West into Limpopo. In the Northern Cape it blamed mostly natural build-up in dry country, and nearly 40 percent of sources there were over the older 20 mg/L standard. More than 20 percent of the (fewer) Free State sources were over it too. Those are old figures against an old standard, so treat them as a pointer to test nitrate, not as a forecast for your borehole. Near a landfill, expect more: monitoring boreholes at two Bloemfontein landfills had lead and arsenic above SANS 241, and TDS above it at the northern site.
Limpopo
At Vyeboom, 11 of 17 sampled boreholes were over the nitrate limit (up to 163 mg/L as nitrate), with farming and nearby pit latrines blamed, and E. coli and total coliforms were higher in the wet season. At Siloam, groundwater fluoride measured 3.92 to 4.95 mg/L against a limit of 1.5. Problems are patchy: every Vyeboom borehole passed on fluoride (0.44 to 0.9 mg/L). A 2010 CSIR update still found Limpopo and the Kalahari region strongly affected by nitrate.
Western Cape
On the Cape Flats the water table is typically 1 to 3 metres below ground, and an Umvoto Africa aquifer assessment hosted by DWS calls this primary aquifer particularly sensitive to contaminants. It reports elevated chloride towards False Bay and elevated nitrate mostly in agricultural boreholes in Ottery, Philippi and Mitchells Plain, and warns that on-site sanitation combined with a high winter water table is a serious health hazard. The 2010 CSIR update said the Western Cape appeared more affected by elevated nitrate than before. In the Table Mountain Group, one DWS review of a Cape Town spring recorded pH below 6, which is corrosive to metal pipes.
KwaZulu-Natal, Mpumalanga, Eastern Cape
We did not find a published source we could open that names a typical problem for these provinces, so we do not guess one. Test for the full list, and treat a clean-looking neighbour's result as no guide to yours.
Wellheads matter too. A Bloemfontein landfill study found E. coli at every borehole at one site and none at the other. Its authors suggested the poor state of the affected borehole may have made it prone to contamination, and cited work linking microbial contamination to construction quality, with boreholes whose mouths sit at ground level doing worse.
The SANS 241 limits that matter
SANS 241 is the South African drinking water standard. A lab report lists each result next to a limit. Health limits (acute and chronic) matter most. Aesthetic limits are about taste and staining, and operational limits are warning signs.
| Lab reports | SANS 241-1:2015 limit | Type | What it means |
|---|---|---|---|
| E. coli | Not detected in 100 mL | Acute health | The only passing result is none detected. Any detection means the water is not safe to drink untreated. |
| Nitrate (as N) | 11 mg/L (roughly 50 mg/L as nitrate) | Acute health | Mainly a danger to babies under six months. Boiling does not remove it. |
| Nitrite (as N) | 0.9 mg/L | Acute health | Reported alongside nitrate. |
| Fluoride | 1.5 mg/L | Chronic health | Above this the risk of dental fluorosis rises. WHO links 3 to 6 mg/L to skeletal fluorosis. |
| Arsenic | 10 micrograms/L | Chronic health | WHO says long-term exposure can cause cancer and skin lesions. |
| Lead | 10 micrograms/L | Chronic health | Listed as a chronic health limit in SANS 241. |
| Sulphate | 500 mg/L (acute), 250 mg/L (aesthetic) | Acute health and aesthetic | Reported on a chemistry package. |
| Iron | 0.3 mg/L aesthetic, 2 mg/L chronic health (2015) | Aesthetic | Staining and a metallic taste at the lower limit. |
| Manganese | 0.1 mg/L aesthetic, 0.4 mg/L chronic health (2015) | Aesthetic | Black staining at the lower limit. |
| Total dissolved solids | 1,200 mg/L (conductivity 170 mS/m) | Aesthetic | A salty or brackish taste. |
| pH | 5 to 9.7 | Operational | Low pH can corrode pipes and fittings. |
| Total coliforms and plate count | 10 per 100 mL and 1,000 per mL | Operational | Indicators that the water or the borehole needs attention. |
Editions. SANS 241 was revised in 2025. A Rand Water specialist on the SABS committee describes SANS 241:2025 as replacing the two-part 2015 edition. The full text is paywalled, so this page quotes the 2015 limits as transcribed by a SANAS laboratory. In the July 2024 public-comment draft of the new edition, E. coli (not detected), nitrate (11 mg/L as N, 50 mg/L as nitrate), fluoride (1.5 mg/L) and arsenic (10 micrograms/L) carry the same numbers, and iron and manganese appear only as aesthetic limits (0.3 and 0.1 mg/L). Ask your lab which edition its report uses.
Check the unit on nitrate. Labs report nitrate either as nitrate (limit about 50 mg/L) or as nitrate-nitrogen (limit 11 mg/L as N). A result of 30 is about three times the limit if it is reported as N, and comfortably under it if it is reported as nitrate.
How to take a sample
A bad sample gives a bad answer. These steps follow the DWS sampling guide for a borehole with a pump. Your lab's own instructions win if they differ.
- 1Phone the lab first. Ask which package covers what you need, collect their bottles, and tell them when you will deliver.
- 2Keep the sterile bacteria bottle closed and clean until the moment you fill it. Wash your hands or wear gloves, and do not touch the neck of the bottle or the inside of the cap.
- 3Use the nearest tap on the line from the borehole pump. A tap after a filter, UV unit or softener gives you treated water, not raw water, so ask the lab which you need.
- 4Open the tap and let the water run to waste for at least 3 minutes.
- 5Do not rinse the bottle. Fill it, then cap it straight away.
- 6Leave an air gap of at least 2.5 cm at the top of the bottle so the lab can mix the sample. Do not fill the bacteria bottle to the brim.
- 7If you are collecting chemistry and bacteria samples at the same tap, fill the bacteria bottle first.
- 8Put the bottles in a cool box, out of sunlight and not frozen, and get them to the lab the same day.
Timing matters. The DWS guide says bacteriological samples should be analysed within 6 hours of sampling if not cooled and within 24 hours if cooled, and a later analysis must be flagged on the report. Chemical samples kept cool should be analysed within 7 days. Deliver the bacteria bottle first and fast.
How often to test
The DWS sampling guide sets a minimum of one sample a year for a borehole and recommends two a year, six months apart, with more sampling when a change in quality is detected. This is guidance for domestic supplies, not a legal schedule for a private household. Test sooner after a flood, a sewage spill or leak nearby, or a change in taste, colour or smell. See the water quality guide for the wider picture.
What a test costs
Indicative, from published prices (H2O Guru, a SANAS-accredited laboratory, checked on 2 October 2026). Prices include VAT. Sampling at your premises or courier collection is offered.
Microbiology only
R895
E. coli, total and faecal coliforms, plate count. About 5 to 7 working days.
Chemistry only
R1,650
Nitrate, nitrite, fluoride, iron, manganese, sulphate, TDS, pH and more. About 5 to 7 working days.
Chemistry plus microbiology
R2,200
Both packages together. About 7 to 10 working days.
Ask for the parameter list before you pay. The R2,200 package above lists fluoride, nitrate, nitrite, iron, manganese, aluminium and sulphate, but it does not list arsenic or lead. A second lab price list, reported by Drillbuilders from 2025, puts a basic potability test at about R818 and says only its packages from about R2,811 include arsenic and uranium. Where the ground can carry arsenic or uranium, a cheap package can miss the one number that matters.
Use a SANAS-accredited laboratory and keep the report: it names the lab, the sample date and point, and each result against the limit. Our water testing guide has more on packages.
While you wait for results
- Use another source for drinking, cooking and brushing teeth until the results arrive, and especially for babies and for formula.
- If you must drink it, bring clear water to a rolling boil for 1 minute (CDC says 3 minutes above 6,500 feet). If it is cloudy, strain it through a clean cloth or coffee filter first. This kills bacteria, viruses and protozoa.
- Do not rely on boiling for anything chemical. It does not remove nitrate (it can raise it), and CDC says boiling or disinfecting cannot make water containing fuel or toxic chemicals safe.
- Do not buy treatment yet. The result tells you which treatment, if any.
- Look at the borehole head. A damaged cap, or a head set at ground level, is associated with bacterial contamination in the Bloemfontein study above. Fix it whatever the result says.
When the answer is: do not drink it
Any of these means stop drinking it untreated. Most can be fixed, so the next step is to treat or switch source and retest, not to give up on the borehole.
| If | Then |
|---|---|
| E. coli is detected | Do not drink it untreated. Boil as a stopgap, find the entry point (wellhead, seal, a leaking latrine or septic tank), fix it, and retest. |
| Nitrate is over 11 mg/L as N | Do not use it for babies or for formula. Boiling makes nitrate worse. Use another source or treat it with reverse osmosis or nitrate-selective ion exchange, then retest. |
| Fluoride is over 1.5 mg/L | Do not give it to children as their daily drinking water. Use another source, or treat it and retest. |
| Arsenic is over 10 micrograms/L | Use another source. WHO lists substituting a low-arsenic source as the first way to cut exposure. Treatment is specialist work. |
| It smells or tastes of fuel or chemicals, or you know of a spill | Do not drink it. CDC says boiling or disinfecting does not make it safe. Use bottled or other water and speak to your municipal environmental health office. |
| There has been a flood, or a sewage spill or leak near the borehole | Do not drink it until a new test passes. |
| You have no result yet and the water is for a baby | Use another source until you do. |
What to do next
Borehole water safety questions
Is borehole water safe to drink?
Not automatically. It can be perfectly good, and it can fail on bacteria, nitrate, fluoride, arsenic or salts, depending on the rock it sits in and what happens on the land around it. A SANS 241 laboratory test is the only way to know, and it should be repeated.
Is clear borehole water safe?
Clear does not mean safe. Bacteria, nitrate, fluoride and arsenic do not change how water looks. A water lab notes that many health-related contaminants have no taste or odour, so do not wait for one to become noticeable.
Can I just boil borehole water?
Boiling is a good stopgap against germs: a rolling boil for 1 minute inactivates bacteria, viruses and protozoa. It does nothing for chemicals. It does not remove nitrate, and boiling can raise it, and CDC says boiling cannot make water containing fuel or toxic chemicals safe.
Is borehole water better than municipal water?
Neither is automatically better. A municipal supply is treated and monitored by a supplier. A private borehole is neither, so what you drink depends on your own test results against SANS 241.
How often should I test my borehole water?
The DWS sampling guide for domestic supplies sets a minimum of one sample a year for a borehole and recommends two a year, six months apart, with more sampling if a change is detected. Test sooner after a flood, a sewage spill or leak nearby, or a change in taste, colour or smell.
My result failed. What now?
Do not panic and do not buy the first filter you are offered. Use another source for drinking meanwhile, find whether a cause on your property can be fixed, then match treatment to the exact result. The borehole water filters guide shows what treats each problem. Retest the treated water to prove it works.
Find out what is in your water
One laboratory report ends the guessing. Take the sample the way the lab asks, and keep the report.
Sources
- SANS 241-1:2015 limits (transcribed by Vinlab, a SANAS laboratory) (all 2015 limits in the table)
- Infrastructure News: SANS 241 has changed (Mariette Swart, Rand Water), 18 August 2026 (SANS 241:2025 replaces the two-part 2015 edition)
- Draft SANS 241 Edition 7, public enquiry stage, 11 July 2024 (draft limits for E. coli, nitrate, fluoride, arsenic, iron, manganese)
- DWS, DWAF, WRC and Department of Health: Quality of Domestic Water Supplies, Volume 2: Sampling Guide (2000) (sampling steps, holding times, testing frequency, land use)
- DWS: Johannesburg 1:500 000 hydrogeological map brochure (Gauteng aquifer vulnerability, nitrate sources, mining)
- Tredoux, Talma and Engelbrecht (CSIR): the increasing nitrate hazard in groundwater in the rural areas, WISA 2000 (nitrate band, Northern Cape natural build-up, province shares)
- Maherry and others (CSIR): state of nitrate pollution in groundwater in South Africa, 2010 (Limpopo, Kalahari and Western Cape trends)
- Scientific Reports: groundwater quality at Vyeboom, Limpopo (2023) (nitrate range, E. coli by season, fluoride results, unit conversion)
- Scientific Reports: fluoride in groundwater at Siloam, Limpopo (2021) (fluoride 3.92 to 4.95 mg/L)
- Umvoto Africa (hosted by DWS): Cape Flats Aquifer situation assessment (water levels, nitrate, chloride, sanitation risk)
- DWS: Groundwater Quality Status for the City of Cape Town (GH4279) (low pH in Table Mountain Group area, one spring)
- Molecules (PMC): non-engineered landfills and groundwater in Bloemfontein (landfill monitoring boreholes, borehole construction)
- WHO: fluoride in drinking-water (background document) (fluorosis ranges)
- WHO: arsenic fact sheet (health effects, alternative sources)
- WQA fact sheet: nitrate and nitrite (infants under six months)
- Oregon State Extension EM 9400: nitrate in your drinking water (boiling does not reduce nitrate)
- CDC: how to make water safe in an emergency (boiling time, fuel and toxic chemicals)
- WHO: boil water (a rolling boil inactivates bacteria, viruses and protozoa)
- Quality Water Lab: activated carbon water filters (many health contaminants have no taste or odour)
- H2O Guru: SANS 241 water testing packages (prices and parameters, checked 2 October 2026)
- Drillbuilders: borehole water quality, SANS 241 limits and lab costs (27 September 2026) (a second lab price ladder, package contents)