Borehole Water Quality Guide
What SANS 241 limits mean, where borehole contamination comes from, what to test for in your province, and how often to test.
Last reviewed . Limits come from SANS 241-1:2015 as transcribed by an accredited lab. Check the current edition with SABS.
SANS 241 was revised in 2025. SANS 241:2025 replaces the 2015 edition, and under it boreholes, tankers and refill stations count as water providers. The limits on this page are from the 2015 edition, which labs still report against widely, so ask your lab which edition its report uses. Infrastructure News, 18 August 2026
Always Test Before Drinking
Clear water does not mean safe water. Many harmful contaminants (bacteria, nitrate, fluoride, heavy metals) are invisible, odourless and tasteless. Test your borehole water at an accredited laboratory before using it for drinking, cooking or bathing. Borehole water is not treated or monitored by anyone, so testing is the only way to know. See Is borehole water safe to drink?
SANS 241 Drinking Water Limits
SANS 241 is the national drinking water specification and the benchmark laboratories test against. We found no rule that audits a private household against it, so treat it as your own safeguard. Iron and manganese have both an aesthetic limit (staining and taste) and a higher health limit, so a result above the aesthetic limit is not automatically a health problem, and a result above the health limit is.
| Parameter | SANS 241 Limit | Risk If Exceeded | Category |
|---|---|---|---|
| pH | 5.0 to 9.7 | Corrosion or scaling; low pH can dissolve copper pipes | Operational |
| Total dissolved solids (TDS) | ≤ 1,200 mg/L | Taste, scaling | Aesthetic |
| Electrical conductivity | ≤ 170 mS/m | Dissolved salts, taste | Aesthetic |
| Nitrate (as N) | ≤ 11 mg/L | Blue baby syndrome in infants | Acute health |
| Nitrite (as N) | ≤ 0.9 mg/L | Acute health risk | Acute health |
| Fluoride | ≤ 1.5 mg/L | Dental and skeletal fluorosis. No taste or smell | Chronic health |
| Iron (Fe), aesthetic limit | ≤ 0.3 mg/L | Staining, metallic taste | Aesthetic |
| Iron (Fe), health limit | ≤ 2.0 mg/L | Long-term health limit | Chronic health |
| Manganese (Mn), aesthetic limit | ≤ 0.1 mg/L | Black staining | Aesthetic |
| Manganese (Mn), health limit | ≤ 0.4 mg/L | Long-term health limit | Chronic health |
| E. coli | Not detected in 100 mL | Gastrointestinal illness | Acute health |
| Total coliforms | ≤ 10 per 100 mL | Indicates contamination | Operational |
| Heterotrophic plate count | ≤ 1,000 per mL | Indicates a system or treatment problem | Operational |
| Arsenic | ≤ 0.01 mg/L | Long-term health risk | Chronic health |
| Lead | ≤ 0.01 mg/L | Long-term health risk | Chronic health |
| Sulphate, acute health limit | ≤ 500 mg/L | Acute health risk at high levels | Acute health |
| Sulphate, aesthetic limit | ≤ 250 mg/L | Taste | Aesthetic |
| Sodium | ≤ 200 mg/L | Salty taste | Aesthetic |
| Chloride | ≤ 300 mg/L | Salty taste | Aesthetic |
What to Test First, by Province
These are priorities, not a replacement for a full panel. Water quality changes within a province and even within a suburb, so only a test on your own borehole tells you what is in it.
Every province
Start with E. coli (acute health, not detected in 100 mL), nitrate (acute health, 11 mg/L as N), and pH and TDS or conductivity as a baseline. Ask the lab for a full SANS 241 panel so nothing local is missed.
Gauteng
Nitrate and microbiology first. The DWS Johannesburg brochure says dolomitic aquifers are especially vulnerable, with nitrate introduced by pit latrines in informal settlements, cattle kraals, sewage plant effluent and excessive fertiliser use. Where mining has affected water, add sulphate, TDS and metals, because the brochure says the contribution of mining to water quality degradation is substantial. Dolomite also carries sinkhole risk, notably in southern Tshwane. See the dolomite section of our permits guide.
North West
Nitrate and fluoride, plus mining effects. A 2000 WISA paper says high nitrate concentrations in groundwater occur mainly in a wide band stretching north-east from the Northern Cape through North West into what is now Limpopo. Fluoride is reported in groundwater in most parts of South Africa.
Limpopo
Fluoride and nitrate first, then TDS and chloride. A published study of Siloam in northern Limpopo reports springs with high fluoride and a large-scale occurrence of dental fluorosis among children and adults.
Free State
Fluoride and salinity (TDS, sodium, chloride). A Water Research Commission report says most Karoo groundwaters have TDS between 450 and 1,000 mg/L, with the highest values in the west and south, so check TDS, sodium and chloride against the SANS 241 limits.
Northern Cape
Salinity (TDS, chloride, sulphate), nitrate and fluoride. This is where the nitrate band described above starts. We found no Northern Cape source of our own, so ask for the full SANS 241 panel.
Western Cape
On the Cape Flats the water table is shallow and easily polluted, so microbiology and nitrate come first, then iron and manganese. In Table Mountain Group sandstone areas expect low pH, iron and manganese. We have not confirmed coastal salinity, so include chloride and TDS.
KwaZulu-Natal
Microbiology first. Fluoride is reported in groundwater in most parts of South Africa, so include it. Coastal salinity from sea-water intrusion is possible but we found no source, so include chloride and TDS.
Mpumalanga and Eastern Cape
We have not researched province-specific priorities. A full SANS 241 panel covers the main health parameters.
Common Contamination Sources
Septic Tanks and Pit Latrines
Contaminants: E. coli, nitrates, phosphates
Prevention: Keep the borehole as far as practicable from septic tanks, soakaways and pit latrines. The safe distance depends on soil and rock, and we could not find an authoritative figure, so do not rely on a rule of thumb: ask your hydrogeologist. Fit a proper sanitary seal on the borehole. The DWS brochure notes that pit latrines have introduced high nitrate into dolomitic aquifers.
Agricultural Runoff
Contaminants: Nitrates, pesticides, herbicides
Prevention: Avoid siting a borehole near fertilised fields or kraals, and test for nitrate regularly.
Natural Geology
Contaminants: Iron, manganese, fluoride, arsenic
Prevention: These occur naturally in some rocks. Fluoride is reported in groundwater in most parts of South Africa, and iron and manganese are a feature of Table Mountain Group sandstone. Treatment is needed if levels exceed SANS 241, and the right treatment depends on the contaminant.
Mining and Industry
Contaminants: Heavy metals, acid mine drainage, sulphate
Prevention: The DWS Johannesburg brochure says the contribution of mining activities to the degradation of water quality is substantial. Get a professional assessment near mining and test comprehensively.
Surface Contamination
Contaminants: Bacteria, fuel, chemicals
Prevention: A sealed cap and headworks and a grouted seal around the casing keep surface water out. Keep chemicals and fuel away from the borehole head.
Recommended Testing Schedule
This is recommended practice, not a legal requirement. We found no South African rule that sets a testing schedule for a private borehole. SANS 241 says what to test, not how often a household must.
Full SANS 241 (chemical and microbiological)
A baseline: know what you are dealing with
Microbiological (E. coli, coliforms), if you drink the water
Catches changes your senses cannot
Full SANS 241 chemical and microbiological
A yearly check against the standard
Full test
Flooding, construction or digging nearby, repairs, or a change in taste, colour or smell
After the Test: Match Treatment to the Result
Most borehole water can be treated to meet SANS 241, but treatment has to be matched to the lab result and the water re-tested afterwards. Some problems, such as high fluoride, arsenic or salinity, need specific technology. Our borehole water filters guide and borehole water page explain the options and their limits.
Get Your Water Tested
Send one request and testing labs and service companies in your area can quote. Ask whether the lab is SANAS accredited for the tests you need.
Sources
- SANS 241-1:2015 drinking water limits (SANAS-accredited lab transcription) (all limits and categories in the table; check SABS for the current edition)
- DWS Johannesburg 1:500 000 hydrogeological map brochure (dolomite vulnerability, nitrate sources, mining effects)
- WISA 2000: the increasing nitrate hazard in groundwater in rural areas (nitrate band from the Northern Cape to Limpopo)
- Fluoride in groundwater and fluorosis at Siloam, Limpopo (Scientific Reports) (fluoride in South African groundwater)
- UWC thesis on Table Mountain Group groundwater quality (iron, manganese and acidity)
- DWS Cape Flats Aquifer report (shallow sandy aquifer)
- Water Research Commission: Karoo aquifers (report 487/1/98) (Karoo groundwater TDS)