Start here: which water do you have?
Brown stains, blocked drippers, brak water, stock that will not drink. Choose your water and the three steps below change to match it: what is usually wrong, what to test, and what fixes it.
Borehole water
In one line: test it once a year, filter the sand, treat iron before it stains, soften only the house and the dairy, and disinfect anything people or stock drink.
Borehole water is untreated groundwater. It is usually clear at the pump and changes as it meets air, and it changes again in a dry year when the water table drops. Four things account for most borehole complaints in South Africa: iron and manganese, hardness, salt, and sand.
What is usually wrong
Match what you see on the farm to what is happening in the water.
- Brown or orange stains on troughs, walls and washing; clear water goes rusty in the tank
- Dissolved iron, invisible at the pump, drops out when it meets air. Black stains are manganese.
- Iron and manganese filter
- White crust on kettles, geysers, drippers and spray nozzles
- Hardness: calcium and magnesium that drop out as lime when the water is heated or its pH rises.
- Water softener
- Water tastes salty; leaf edges burn; stock drink less
- Salinity, mostly sodium chloride. Read the EC line first, then sodium and chloride.
- Reverse osmosis for brak water
- Sand or grit in the water; pump and valves wear; drippers block
- Fine sand from the aquifer or a failing well screen.
- Sediment filter
- Rotten-egg smell at the tap
- Hydrogen sulphide from bacteria in the borehole. It oxidises away with air or chlorine, usually in the same step as the iron.
- Iron and manganese filter
- Blue-green stains, sour taste, copper pipes pitting
- Low pH: sour water that dissolves copper and steel.
- pH correction
- Nitrate on the certificate; a kraal, feedlot or septic tank nearby
- Nitrate seeps in from manure, fertiliser and septic tanks. It is a health number for babies and pregnant stock, and a sign the borehole is poorly protected.
- Reverse osmosis for brak water
What to test, and what the numbers mean
One laboratory analysis answers most questions. These are the lines to read first for this water, with the South African guideline numbers in plain words.
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| EC or TDS (the salt) | How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak. | Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only. | Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly. | Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that. |
| Hardness (the lime) | Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles. | Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water. | Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows). | SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb). |
| Iron | Dissolved iron is invisible at the pump and turns brown or orange when it meets air. | Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5. | Stains troughs and puts stock off the taste; not toxic at farm levels. | Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings. |
| Manganese | Iron's cousin. Black or purple stains and a metallic taste. | Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging. | Taste and staining only. | Under 0.1 mg/L (SANS 241). |
| Nitrate | Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4. | A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected. | Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first. | Under 11 mg/L as N (SANS 241). Babies are the reason. |
| Sulphate | A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium. | Not a crop problem at farm levels; it counts toward the EC. | Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first. | Under 250 mg/L for taste, 500 for health (SANS 241). |
| pH (sour or alkaline) | Below 7 the water is acidic and eats metal; above 8 it drops lime scale. | 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale. | Rarely a problem for stock on its own. | 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode. |
Read these first for this water
EC or TDS (the salt)
How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak.
- Irrigation
- Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only.
- Livestock
- Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly.
- House and dairy
- Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that.
Hardness (the lime)
Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles.
- Irrigation
- Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water.
- Livestock
- Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows).
- House and dairy
- SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb).
Iron
Dissolved iron is invisible at the pump and turns brown or orange when it meets air.
- Irrigation
- Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5.
- Livestock
- Stains troughs and puts stock off the taste; not toxic at farm levels.
- House and dairy
- Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings.
Manganese
Iron's cousin. Black or purple stains and a metallic taste.
- Irrigation
- Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging.
- Livestock
- Taste and staining only.
- House and dairy
- Under 0.1 mg/L (SANS 241).
Nitrate
Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4.
- Irrigation
- A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected.
- Livestock
- Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first.
- House and dairy
- Under 11 mg/L as N (SANS 241). Babies are the reason.
Sulphate
A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium.
- Irrigation
- Not a crop problem at farm levels; it counts toward the EC.
- Livestock
- Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first.
- House and dairy
- Under 250 mg/L for taste, 500 for health (SANS 241).
pH (sour or alkaline)
Below 7 the water is acidic and eats metal; above 8 it drops lime scale.
- Irrigation
- 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale.
- Livestock
- Rarely a problem for stock on its own.
- House and dairy
- 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode.
Show every line on the certificateShow only the lines for this water
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| Sodium | Half of table salt. Burns leaves under sprinklers and seals the soil over time. | Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops. | Under 2 000 mg/L. | Under 200 mg/L (SANS 241). |
| Chloride | The other half of table salt. Leaf-edge burn on sensitive crops. | Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones. | Under 1 500 mg/L. | Under 250 mg/L (SANS 241). |
| Fluoride | Natural in some aquifers. Mottled teeth in children and stock. | Under 2 mg/L for long-term irrigation. | Under 2 mg/L. Above 4, lameness in ruminants. | Under 1.5 mg/L (SANS 241). |
| E. coli and coliforms (the germs) | Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in. | Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only. | Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry. | No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions. |
| Turbidity and solids (the mud) | Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine. | Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless. | Stock drink muddy water; the problem is what grows in it. | Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass. |
The rest of the certificate
Sodium
Half of table salt. Burns leaves under sprinklers and seals the soil over time.
- Irrigation
- Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops.
- Livestock
- Under 2 000 mg/L.
- House and dairy
- Under 200 mg/L (SANS 241).
Chloride
The other half of table salt. Leaf-edge burn on sensitive crops.
- Irrigation
- Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones.
- Livestock
- Under 1 500 mg/L.
- House and dairy
- Under 250 mg/L (SANS 241).
Fluoride
Natural in some aquifers. Mottled teeth in children and stock.
- Irrigation
- Under 2 mg/L for long-term irrigation.
- Livestock
- Under 2 mg/L. Above 4, lameness in ruminants.
- House and dairy
- Under 1.5 mg/L (SANS 241).
E. coli and coliforms (the germs)
Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in.
- Irrigation
- Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only.
- Livestock
- Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry.
- House and dairy
- No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions.
Turbidity and solids (the mud)
Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine.
- Irrigation
- Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless.
- Livestock
- Stock drink muddy water; the problem is what grows in it.
- House and dairy
- Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass.
Sources: SANS 241:2025 for the house; DWAF 1996 South African Water Quality Guidelines vol. 4 (irrigation) and vol. 5 (livestock); FAO 29 where the guideline is silent. Rules of thumb are marked.
What fixes it
In the order the water goes through them. Every fix links to a plain-language guide and, where it helps, a calculator.
Sediment filter
Sand, grit, silt; anything ahead of drippers, UV or a membrane.
A backwashing sand or glass filter for volume, a disc filter for drip lines, a cartridge for the house. Filter to a tenth of the smallest passage downstream.
Iron and manganese filter
Brown or black staining, rusty tank water, rotten-egg smell, iron slime in drippers.
Oxidise the iron on purpose, with air or a little chlorine, then trap it on a catalytic media bed that backwashes itself. The same bed handles manganese and the smell.
pH correction
Sour water that eats copper, steel and concrete; rain tanks; sandy-country boreholes.
The water runs through a bed of crushed limestone that dissolves just enough to bring the pH up. No chemicals, no dosing.
Water softener
Hard water in the house, the dairy, the boiler or the poultry line. Never for irrigation.
Swaps the calcium and magnesium for sodium on a resin bed and regenerates with salt. Sized on hardness and daily use, with a meter so it regenerates on use, not on the clock.
Acid dosing for drip lines
Lime scale in drippers and nozzles from hard, alkaline water.
A small metering pump brings the pH down to about 6.5 so the lime stays dissolved. This is the right answer for irrigation; a softener is not, because it adds sodium to the soil.
Reverse osmosis for brak water
Salty water for the house, the dairy, poultry or pigs, or to blend down a brak irrigation supply for high-value crops.
Pushes the water through a membrane that holds the salt back. Part of the water goes to waste, so it is sized on how much you need, not how much you pump, and the permeate is blended back so the water is not too pure for soil or pipes.
UV or chlorine
E. coli or coliforms on the certificate; any dam or river water for people, the dairy or the drinking lines.
UV kills what passes through it and adds nothing; chlorine keeps working down the pipe and into the tank. Both need clear, filtered water first, and a dairy or drinking line usually wants both.
Dam and river water
In one line: settle and filter it, disinfect it, and test it in the hot months; clear water is not the same as clean water.
Surface water is weather you can pump. Clear one week and mud the next; warm and still in autumn it grows algae, and every animal upstream contributes. It needs three things in order: settling and filtering, disinfection, and a test in the hot months.
What is usually wrong
Match what you see on the farm to what is happening in the water.
- Muddy water after rain; filters and drippers block; pumps wear
- Silt and clay so fine it never settles on its own.
- Settling and filtering dam water
- Green water, slime in the pipes, a scum on the dam
- Algae. Blue-green algae in a warm, still dam make toxins that can kill stock overnight. Keep stock off a blooming dam and do not pump from it.
- Settling and filtering dam water
- Runny stomachs in the house; E. coli or coliforms on the certificate
- Stock, birds and a river upstream. Surface water is never safe to drink without disinfection.
- UV or chlorine
- Brown but clear water that tastes of the veld
- Dissolved organics from peat and leaves. Colour and taste, and they use up chlorine.
- Activated carbon
What to test, and what the numbers mean
One laboratory analysis answers most questions. These are the lines to read first for this water, with the South African guideline numbers in plain words.
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| Turbidity and solids (the mud) | Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine. | Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless. | Stock drink muddy water; the problem is what grows in it. | Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass. |
| E. coli and coliforms (the germs) | Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in. | Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only. | Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry. | No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions. |
| pH (sour or alkaline) | Below 7 the water is acidic and eats metal; above 8 it drops lime scale. | 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale. | Rarely a problem for stock on its own. | 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode. |
| EC or TDS (the salt) | How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak. | Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only. | Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly. | Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that. |
| Iron | Dissolved iron is invisible at the pump and turns brown or orange when it meets air. | Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5. | Stains troughs and puts stock off the taste; not toxic at farm levels. | Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings. |
Read these first for this water
Turbidity and solids (the mud)
Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine.
- Irrigation
- Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless.
- Livestock
- Stock drink muddy water; the problem is what grows in it.
- House and dairy
- Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass.
E. coli and coliforms (the germs)
Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in.
- Irrigation
- Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only.
- Livestock
- Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry.
- House and dairy
- No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions.
pH (sour or alkaline)
Below 7 the water is acidic and eats metal; above 8 it drops lime scale.
- Irrigation
- 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale.
- Livestock
- Rarely a problem for stock on its own.
- House and dairy
- 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode.
EC or TDS (the salt)
How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak.
- Irrigation
- Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only.
- Livestock
- Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly.
- House and dairy
- Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that.
Iron
Dissolved iron is invisible at the pump and turns brown or orange when it meets air.
- Irrigation
- Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5.
- Livestock
- Stains troughs and puts stock off the taste; not toxic at farm levels.
- House and dairy
- Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings.
Show every line on the certificateShow only the lines for this water
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| Hardness (the lime) | Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles. | Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water. | Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows). | SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb). |
| Manganese | Iron's cousin. Black or purple stains and a metallic taste. | Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging. | Taste and staining only. | Under 0.1 mg/L (SANS 241). |
| Sodium | Half of table salt. Burns leaves under sprinklers and seals the soil over time. | Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops. | Under 2 000 mg/L. | Under 200 mg/L (SANS 241). |
| Chloride | The other half of table salt. Leaf-edge burn on sensitive crops. | Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones. | Under 1 500 mg/L. | Under 250 mg/L (SANS 241). |
| Sulphate | A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium. | Not a crop problem at farm levels; it counts toward the EC. | Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first. | Under 250 mg/L for taste, 500 for health (SANS 241). |
| Nitrate | Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4. | A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected. | Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first. | Under 11 mg/L as N (SANS 241). Babies are the reason. |
| Fluoride | Natural in some aquifers. Mottled teeth in children and stock. | Under 2 mg/L for long-term irrigation. | Under 2 mg/L. Above 4, lameness in ruminants. | Under 1.5 mg/L (SANS 241). |
The rest of the certificate
Hardness (the lime)
Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles.
- Irrigation
- Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water.
- Livestock
- Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows).
- House and dairy
- SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb).
Manganese
Iron's cousin. Black or purple stains and a metallic taste.
- Irrigation
- Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging.
- Livestock
- Taste and staining only.
- House and dairy
- Under 0.1 mg/L (SANS 241).
Sodium
Half of table salt. Burns leaves under sprinklers and seals the soil over time.
- Irrigation
- Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops.
- Livestock
- Under 2 000 mg/L.
- House and dairy
- Under 200 mg/L (SANS 241).
Chloride
The other half of table salt. Leaf-edge burn on sensitive crops.
- Irrigation
- Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones.
- Livestock
- Under 1 500 mg/L.
- House and dairy
- Under 250 mg/L (SANS 241).
Sulphate
A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium.
- Irrigation
- Not a crop problem at farm levels; it counts toward the EC.
- Livestock
- Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first.
- House and dairy
- Under 250 mg/L for taste, 500 for health (SANS 241).
Nitrate
Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4.
- Irrigation
- A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected.
- Livestock
- Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first.
- House and dairy
- Under 11 mg/L as N (SANS 241). Babies are the reason.
Fluoride
Natural in some aquifers. Mottled teeth in children and stock.
- Irrigation
- Under 2 mg/L for long-term irrigation.
- Livestock
- Under 2 mg/L. Above 4, lameness in ruminants.
- House and dairy
- Under 1.5 mg/L (SANS 241).
Sources: SANS 241:2025 for the house; DWAF 1996 South African Water Quality Guidelines vol. 4 (irrigation) and vol. 5 (livestock); FAO 29 where the guideline is silent. Rules of thumb are marked.
What fixes it
In the order the water goes through them. Every fix links to a plain-language guide and, where it helps, a calculator.
Sediment filter
Sand, grit, silt; anything ahead of drippers, UV or a membrane.
A backwashing sand or glass filter for volume, a disc filter for drip lines, a cartridge for the house. Filter to a tenth of the smallest passage downstream.
Settling and filtering dam water
Muddy, coloured or green water from a dam or river.
A coagulant makes the fine clay and algae clump so a media filter can catch it; carbon takes the colour and taste. Only then does disinfection work.
Activated carbon
Taste, smell and colour; chlorine before a membrane or a resin.
Adsorbs organics and chlorine on a bed of carbon. It does not remove salt, hardness or germs.
UV or chlorine
E. coli or coliforms on the certificate; any dam or river water for people, the dairy or the drinking lines.
UV kills what passes through it and adds nothing; chlorine keeps working down the pipe and into the tank. Both need clear, filtered water first, and a dairy or drinking line usually wants both.
Rain and backup water
In one line: keep the roof out of the tank, keep the light out, and treat what comes out with a cartridge, carbon and UV before anyone drinks it.
Rain off a clean roof is soft, slightly sour and nearly salt-free. What it carries is whatever was on the roof and in the gutters: dust, bird droppings, leaves. Backup water, whether from the municipal line or a tanker, is only as good as the tank it sits in.
What is usually wrong
Match what you see on the farm to what is happening in the water.
- Runny stomachs; a musty smell from the tank
- Bird droppings and leaf litter washed off the roof; germs and organics in the tank.
- Tank and roof hygiene
- Sour water; green stains on the sink; a geyser element that does not last
- Rainwater has no lime to buffer it, so its pH sits low and it dissolves copper and steel.
- pH correction
- Chlorine smell gone; the backup tank goes off after a week
- Municipal chlorine fades in a warm tank. Re-treat at the tap.
- UV or chlorine
- Brown water after a tanker fill
- Sediment stirred up in the tank, or rust from the truck.
- Sediment filter
What to test, and what the numbers mean
One laboratory analysis answers most questions. These are the lines to read first for this water, with the South African guideline numbers in plain words.
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| E. coli and coliforms (the germs) | Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in. | Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only. | Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry. | No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions. |
| pH (sour or alkaline) | Below 7 the water is acidic and eats metal; above 8 it drops lime scale. | 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale. | Rarely a problem for stock on its own. | 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode. |
| Turbidity and solids (the mud) | Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine. | Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless. | Stock drink muddy water; the problem is what grows in it. | Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass. |
Read these first for this water
E. coli and coliforms (the germs)
Faecal contamination: stock, birds, a septic tank, a dam upstream. E. coli means faeces and must be absent from drinking water; coliforms on their own still mean something is getting in.
- Irrigation
- Under 1 per 100 mL for anything eaten raw. 1 to 1 000 only on crops not eaten raw, with the fruit kept dry. Above that, fodder only.
- Livestock
- Under 200 faecal coliforms per 100 mL. 200 to 1 000 is a real risk to young stock, pigs and poultry.
- House and dairy
- No E. coli in 100 mL and total coliforms under 10 (SANS 241). No exceptions.
pH (sour or alkaline)
Below 7 the water is acidic and eats metal; above 8 it drops lime scale.
- Irrigation
- 6.5 to 8.4. Below, fittings corrode and leaves burn; above, nutrients lock up and drippers scale.
- Livestock
- Rarely a problem for stock on its own.
- House and dairy
- 5 to 9.7 is within SANS 241, but below about 6.5 copper and steel pipes corrode.
Turbidity and solids (the mud)
Sand, silt, clay and algae that block filters and drippers and shield germs from UV and chlorine.
- Irrigation
- Drip: under 50 mg/L suspended solids is practically no clogging; 50 to 100 slight to moderate; above 100 severe. Filter drip water regardless.
- Livestock
- Stock drink muddy water; the problem is what grows in it.
- House and dairy
- Under 1 NTU (SANS 241). Below 5 it still looks clear in a glass.
Show every line on the certificateShow only the lines for this water
| The line on the certificate | What it tells you | Irrigation | Livestock | House and dairy |
|---|---|---|---|---|
| EC or TDS (the salt) | How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak. | Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only. | Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly. | Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that. |
| Hardness (the lime) | Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles. | Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water. | Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows). | SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb). |
| Iron | Dissolved iron is invisible at the pump and turns brown or orange when it meets air. | Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5. | Stains troughs and puts stock off the taste; not toxic at farm levels. | Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings. |
| Manganese | Iron's cousin. Black or purple stains and a metallic taste. | Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging. | Taste and staining only. | Under 0.1 mg/L (SANS 241). |
| Sodium | Half of table salt. Burns leaves under sprinklers and seals the soil over time. | Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops. | Under 2 000 mg/L. | Under 200 mg/L (SANS 241). |
| Chloride | The other half of table salt. Leaf-edge burn on sensitive crops. | Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones. | Under 1 500 mg/L. | Under 250 mg/L (SANS 241). |
| Sulphate | A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium. | Not a crop problem at farm levels; it counts toward the EC. | Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first. | Under 250 mg/L for taste, 500 for health (SANS 241). |
| Nitrate | Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4. | A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected. | Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first. | Under 11 mg/L as N (SANS 241). Babies are the reason. |
| Fluoride | Natural in some aquifers. Mottled teeth in children and stock. | Under 2 mg/L for long-term irrigation. | Under 2 mg/L. Above 4, lameness in ruminants. | Under 1.5 mg/L (SANS 241). |
The rest of the certificate
EC or TDS (the salt)
How much dissolved salt the water carries. EC in mS/m times 6.5 is roughly TDS in mg/L. This is what farmers call brak.
- Irrigation
- Under 40 mS/m no yield loss, even for salt-sensitive crops. 40 to 90 fine for most crops. 90 to 270 for tolerant crops with extra water to leach. Above that, selected crops only.
- Livestock
- Dairy cows, pigs and poultry under 1 000 mg/L. Beef cattle and horses under 2 000. Sheep under 3 000. Above these, stock drink less; adapted sheep and cattle cope higher, but never switch them suddenly.
- House and dairy
- Under 170 mS/m, about 1 200 mg/L (SANS 241). It tastes salty well before that.
Hardness (the lime)
Calcium and magnesium, as mg/L CaCO₃. The white crust on kettles, geysers and nozzles.
- Irrigation
- Not a crop problem. Above about 150 mg/L with a pH over 7.5, drippers and nozzles scale (rule of thumb). Never soften irrigation water.
- Livestock
- Not a problem. Calcium up to 1 000 mg/L and magnesium up to 500 are within the guideline (250 for poultry, pigs, horses and dairy cows).
- House and dairy
- SANS 241 sets no limit. Scale shows from about 120 mg/L and a softener pays for itself from about 200 (rule of thumb).
Iron
Dissolved iron is invisible at the pump and turns brown or orange when it meets air.
- Irrigation
- Drip: under 0.2 mg/L minor, 0.2 to 1.5 moderate, above 1.5 severe clogging. Crops themselves tolerate up to 5.
- Livestock
- Stains troughs and puts stock off the taste; not toxic at farm levels.
- House and dairy
- Under 0.3 mg/L (SANS 241). Above it, stained washing and fittings.
Manganese
Iron's cousin. Black or purple stains and a metallic taste.
- Irrigation
- Drip: under 0.1 mg/L minor, 0.1 to 1.5 moderate, above 1.5 severe clogging.
- Livestock
- Taste and staining only.
- House and dairy
- Under 0.1 mg/L (SANS 241).
Sodium
Half of table salt. Burns leaves under sprinklers and seals the soil over time.
- Irrigation
- Sprinklers and pivots (leaves wetted): under 70 mg/L. Drip and flood: judged on SAR, under 2 for sensitive crops.
- Livestock
- Under 2 000 mg/L.
- House and dairy
- Under 200 mg/L (SANS 241).
Chloride
The other half of table salt. Leaf-edge burn on sensitive crops.
- Irrigation
- Under 100 mg/L for all crops. 100 to 175 injures sensitive crops under sprinklers; 175 to 350 moderately sensitive ones.
- Livestock
- Under 1 500 mg/L.
- House and dairy
- Under 250 mg/L (SANS 241).
Sulphate
A bitter salt that runs stock's stomachs and ties up their copper, zinc and selenium.
- Irrigation
- Not a crop problem at farm levels; it counts toward the EC.
- Livestock
- Under 1 000 mg/L. 1 000 to 1 500 gives diarrhoea and puts stock off the water; young stock first.
- House and dairy
- Under 250 mg/L for taste, 500 for health (SANS 241).
Nitrate
Comes from manure, fertiliser and septic tanks. Invisible, tasteless, and a real health number. Check the unit: labs report it as N or as nitrate, and the two differ by a factor of 4.4.
- Irrigation
- A fertiliser credit, not a problem, until about 30 mg/L as N, where most crops are affected.
- Livestock
- Under 100 mg/L as nitrate (22 as N). Above it, pregnant animals are at risk first.
- House and dairy
- Under 11 mg/L as N (SANS 241). Babies are the reason.
Fluoride
Natural in some aquifers. Mottled teeth in children and stock.
- Irrigation
- Under 2 mg/L for long-term irrigation.
- Livestock
- Under 2 mg/L. Above 4, lameness in ruminants.
- House and dairy
- Under 1.5 mg/L (SANS 241).
Sources: SANS 241:2025 for the house; DWAF 1996 South African Water Quality Guidelines vol. 4 (irrigation) and vol. 5 (livestock); FAO 29 where the guideline is silent. Rules of thumb are marked.
What fixes it
In the order the water goes through them. Every fix links to a plain-language guide and, where it helps, a calculator.
Tank and roof hygiene
Rain tanks, backup tanks and any tank that goes green.
Gutter screens and a first-flush diverter keep the roof out of the tank; an opaque, covered tank keeps the light out; a cartridge and UV or a little chlorine at the tap make it drinkable. Clean the tank.
Sediment filter
Sand, grit, silt; anything ahead of drippers, UV or a membrane.
A backwashing sand or glass filter for volume, a disc filter for drip lines, a cartridge for the house. Filter to a tenth of the smallest passage downstream.
pH correction
Sour water that eats copper, steel and concrete; rain tanks; sandy-country boreholes.
The water runs through a bed of crushed limestone that dissolves just enough to bring the pH up. No chemicals, no dosing.
UV or chlorine
E. coli or coliforms on the certificate; any dam or river water for people, the dairy or the drinking lines.
UV kills what passes through it and adds nothing; chlorine keeps working down the pipe and into the tank. Both need clear, filtered water first, and a dairy or drinking line usually wants both.
Keeping it working between service visits
Farm water equipment usually fails quietly, and the first sign is a stained bath, a blocked dripper or a sick animal rather than an alarm. A few readings written down turn that into something you can act on early.
Have this to hand
- The last water analysis, and where and when the sample was taken.
- What each vessel contains and how old the media is: sand, glass, catalytic media and resin all have different lives.
- Pump pressure and the pressure either side of the filters, written down at the same time each week.
- The valve settings as they were commissioned, so you can tell later whether somebody changed them.
What a change usually means
- Drippers blocking faster than they used to
- The filter ahead of them is past its useful life, the media bed is fouled, or the water itself has changed with the season. Check the filter first; it is the cheapest of the three to fix.
- Orange staining that was not there last season
- Iron rising as the water table drops, or a catalytic bed that has lost its coating. Boreholes change through a dry year, which is why a single old analysis is not an answer.
- Pump running longer for the same job
- Something downstream is restricting: blocked cartridges, a fouled bed, or a valve stuck part-way through its cycle. It also costs electricity every day it goes unnoticed.
- UV on a drinking line with a lamp older than a year
- Replace it on the manufacturer's schedule and clean the sleeve at the same time. A glowing lamp is not evidence of a working dose, and on stock and household water that matters.
What to send us
- Which supply and which line: borehole, dam, rain tank, house, dairy or irrigation.
- What changed and when, including the season and any recent rain.
- Your pressure readings and how they compare with a few months ago.
- The last analysis, and a photograph of the installation.
Service intervals, cleaning methods and replacement parts come from the manufacturer's instructions for your actual equipment. What is here helps you notice a change and describe it accurately; it does not replace that documentation, and it is not a substitute for the installer where the work needs one.
Things people hear that are not true
The ones we correct most often.
It looks clear and tastes fine, so it is safe.
Bacteria, nitrate and fluoride have no look, taste or smell. Only the laboratory sees them.
It passed the drinking-water test, so it is fine for the pivot and the sheep.
Different guidelines. Drinking water may carry 200 mg/L sodium; a sprinkler wants under 70. And sheep drink happily above the household salt limit.
Hard water and brak water are the same thing.
Hardness is lime (calcium and magnesium); brak is total salt. A softener does nothing for brak water.
Boil it and the salt goes.
Boiling concentrates salt. Only reverse osmosis or distillation takes it out.
A filter will sort out the iron and the smell.
A cartridge or sand filter only catches iron that has already turned to rust. Dissolved iron and the smell need oxidising first, then a filter that backwashes.
Softened water is fine for the garden.
A softener swaps calcium for sodium, and sodium seals soil. Keep softened water in the house.
One test is enough.
Water changes with drought, storms, over-pumping and the season. Test yearly and when anything changes.
If the animals are not dying, the water is fine.
Stock drink less and produce less long before they die. The guideline is written around intake, not mortality.
The questions we get asked
Short answers. Every one ends in a next step.
Can I drink my borehole water?
Only after a laboratory test. A clear, good-tasting borehole can still fail on bacteria or nitrate, which you cannot see or taste. Test against SANS 241 once a year and again after a drought.
Why does my clear borehole water turn brown in the tank?
Dissolved iron. It is invisible under the ground and turns to rust the moment it meets air. The fix is to oxidise it on purpose and filter it out before the tank, not to scrub the tank.
Can I use a household softener on my irrigation water?
No. A softener swaps calcium for sodium, and sodium is what seals soil and burns leaves. For scale in drippers, dose acid; for brak water, blend or use reverse osmosis on the part that needs it.
How brak can the water be for my cattle and sheep?
The South African guideline gives sheep up to 3 000 mg/L total dissolved salts, beef cattle and horses 2 000, and dairy cows, pigs and poultry 1 000, provided sulphate and magnesium are also in range. Above these, animals drink less and the young and pregnant suffer first.
My drippers block every season. What is it?
One of four things: sand (filter finer), lime scale from hard alkaline water (dose acid), iron slime from water above 0.2 mg/L iron (oxidise and filter), or algae from a dam (filter and chlorinate). The certificate tells you which.
What is the difference between EC and TDS?
The same salt, measured two ways. EC is how well the water conducts electricity, in mS/m; TDS is the weight of dissolved salt in mg/L. Multiply EC in mS/m by about 6.5 to get TDS.
Does the water change in a drought?
Yes. As the water table drops the borehole draws from deeper, older water that is usually saltier and harder, and iron often changes with it. Last year's certificate may not describe this year's water.
The water smells of rotten eggs. Can that be fixed?
Yes. The smell is hydrogen sulphide from bacteria in the borehole. Aeration or a small chlorine dose oxidises it away, and the same filter that handles iron takes the rest.
Is reverse osmosis worth it on a farm?
For drinking water in the house, the dairy or the poultry and pig lines, often yes. For whole-field irrigation the volume and the reject water make it rare; blending a brak supply with better water usually wins.
Blue-green algae in my dam: is it dangerous for stock?
Very. The toxins kill cattle and sheep, sometimes overnight. Fence stock off a blooming dam, do not pump from it for drinking lines, and treat the cause: warm, still, nutrient-rich water.
Can I drink water from my rain tank?
With a first-flush diverter, a fine filter and UV or a little chlorine at the tap, yes. Have it tested once, keep the tank covered and dark, and clean it.
How often should I test?
A full analysis when the borehole is commissioned, then once a year, and again whenever something changes: after a drought, after big storms, when the taste or colour shifts, or when you have over-pumped. Poultry, pigs and dairy lines: every six months, at the source and at the last drinker.
Can I just use a hand-held EC or pH meter?
For tracking change between lab tests, yes; it is the best money a farmer spends on water. It cannot see bacteria, nitrate, fluoride, iron or the sodium hazard, so it does not replace the laboratory.
The borehole yield has dropped and the water is red and slimy. What is that?
Iron bacteria. They move in when oxygen gets into an iron-rich aquifer, usually because the borehole is over-pumped. Ease the pumping (a smaller pump and a bigger tank), have the borehole shock-chlorinated and brushed early, then treat the iron continuously. Left alone it can seal the borehole for good.
My animals drink less since the new borehole, and some have runny stomachs.
Reluctance to drink is the first sign that the salt, sulphate or magnesium is above the guideline for that class of animal, and diarrhoea follows sulphate above about 1 000 mg/L. Production drops long before anything dies. Introduce a new water gradually, mixed with the old, over a week or more. And if the result is fine but they still will not drink, taste the trough: slime and algae in the tank and pipes put stock off long before the chemistry does.
Can I put copper sulphate in the troughs to stop the slime?
Not where sheep or Jersey cattle drink: copper builds up in the liver and poisons them slowly. Shade the trough, scrub it, and use a low dose of chlorine or a peroxide product made for stock water.
Is my borehole fine for the broilers and the drinker lines?
Poultry and pigs are the least salt-tolerant animals on the farm: under 1 000 mg/L dissolved salts, low nitrate, and clean lines. Test at the source and at the last nipple, keep a chlorine residual to the end of the line, and descale the lines between flocks.
The export inspector wants water tests. What do they look for?
A yearly risk assessment with samples from a SANAS lab, E. coli as the indicator, no wetting of the fruit near harvest, and drinking-quality water in the pack-house. The audit schemes also check the water your workers drink.
Does that magnetic or catalytic descaler pipe really work?
We have not seen independent proof, and the Landbou experts warn against wonder cures for the same reason. Ion-exchange softening and reverse osmosis are the proven routes for the house. Whatever anyone sells you, ask for a before-and-after analysis from a laboratory.
Two boreholes 80 m apart, one full of lime and the other not. How?
They are drawing from different water: a different depth, a different rock, sometimes a different aquifer altogether. Test each borehole on its own and treat or blend per source; one certificate does not describe the farm.
My herbicide does not work like it used to. Can it be the water?
Often. Hard, alkaline or brak water ties up glyphosate and several other chemicals in the tank before they reach the leaf. Test the spray water for hardness, pH and bicarbonate, and use a buffer or water conditioner where the label allows.
How much water do my animals actually drink?
Enough to size a treatment system on. Sheep two to six litres a day and up to twelve on saltbush; cattle 25 to 140 litres depending on size, heat and lactation; a dairy cow about five litres for every litre of milk on top of her own maintenance drinking. Heat and salt in the water push all of these up, and parlour washing is a separate demand again.
Do I need a permit to use my borehole?
Household use and stock watering within your grazing capacity are Schedule 1 use under the National Water Act and need no licence. Above about 10 m³ a day you register the use with the Department of Water and Sanitation, the General Authorisation caps irrigation from groundwater in your area, and commercial irrigation beyond it, feedlots and dairies need a water use licence. Your catchment management agency is the place to check.
What does treatment cost?
It depends on the water and on how much of it you need each day, so we do not publish prices. Send the branch your certificate and your daily volume and you get a quote with lead times.
Talk to a person
Phone or WhatsApp the branch nearest you. Send a photo of your water certificate and we will tell you what we see. We quote from your analysis and your flow, and we do not publish prices.
Cape Town
5 Firgrove Way, Firgrove Industrial Estate, Macassar, 7134
Mon to Thu 08:30 to 16:30, Fri 08:30 to 16:00
sales@definitivewater.co.zaJohannesburg
Unit 067, Inospace Allandale Exchange, 917 Morkels Close, Halfway House, Midrand, 1685
Mon to Thu 08:30 to 16:30, Fri 08:30 to 16:00
salesjhb@definitivewater.co.zaGuides, episodes and calculators
Eleven plain-language guides on farm water, each with a podcast episode, in English and Afrikaans.
- Borehole water in drought
- Reading an irrigation water analysis
- Livestock drinking water
- Why drippers block
- Farm dams and rivers
- Spray water quality
- Fertigation
- Dairy water
- Poultry and piggery drinking lines
- Pack-house wash water
- Drought-proofing the farm supply
Treatment train designersoon
Type in your certificate and get a suggested treatment train. Opening soon, as a calculator, not a guarantee.
/designThis page is general guidance for South African farm water. Guideline numbers are indicative; a laboratory analysis and a branch conversation come before any purchase.
These guides are general information, compiled from published standards, manufacturer data and our own experience, and we keep them as accurate as we can. They are not a design, a specification or advice for a particular site. Whoever specifies, installs or operates a system, whether an engineer, an installer, a farmer or a plant manager, remains responsible for checking that what is written here applies to their water and their installation, and for the work itself. Definitive Water Technologies accepts no liability for errors in these pages or for work done on the strength of them. When in doubt, send us the analysis and talk to the branch.