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Borehole Water Filters and Filtration Systems

There is no single borehole water filter. Each stage treats one kind of problem, and the problem is found by a laboratory test, not by looking at the water. This page matches what you see, or what your lab report says, to the treatment that works, and is honest about what each one cannot do.

Last reviewed . Prices are indicative, from published prices, checked on 2 October 2026. They are not quotes.

For a short overview of borehole water, see the borehole water guide.

Test first, then choose the filter

Choose treatment from a laboratory report, not from the colour of the water. A report written against SANS 241 tells you which limits are exceeded and by how much. Many things that matter to health have no visible sign, taste or smell, so a filter bought for staining will not touch them.

Treatment is also not a substitute for finding the cause. Minnesota's health department advises removing the source of contamination first where you can, and notes that units which are not maintained lose their effectiveness and can make water quality worse.

Get your water testedIs borehole water safe to drink?

Borehole filters: what treats what

Find the problem you can see, or the one your lab report flags, and read across. Limits are those in SANS 241-1:2015, the edition most lab reports still quote (see the note on editions on the safe-to-drink guide).

ProblemWhat you may seeLimit to look forWhat treats itWhat does not, and limitsCheck on the lab report
SedimentCloudy, sandy or silty water, grit in a glass.Turbidity: 1 NTU operational limit, 5 NTU aesthetic limit.A sediment cartridge, or a backwashing media filter for heavier loads. It is normally the first stage, because it protects UV and RO downstream.Dissolved iron, nitrate, fluoride, salts and germs pass straight through a sediment filter. Sand can also lock a pump, so tell your pump installer if the water is sandy.Turbidity on the lab report, plus how fast cartridges clog.
Iron and manganese stainingOrange or brown stains (iron), black or brown-black stains (manganese), a metallic taste.Iron 0.3 mg/L and manganese 0.1 mg/L (aesthetic). The 2015 edition also lists chronic health limits of 2 and 0.4 mg/L.An oxidising media filter (Birm, Katalox and manganese greensand types) for moderate levels, up to a combined 1 mg/L in the Nebraska Extension guide. Aeration followed by filtration for higher levels, roughly 5 to 10 mg/L combined.UV, carbon and a plain cartridge do not remove dissolved iron. A softener copes only with low levels (below about 5 mg/L iron and 0.5 mg/L manganese). Oxidising media also need the right water: one supplier lists pH 6.8 to 9.0 for a Birm unit, so acidic water may need correcting first.Iron, manganese, pH and alkalinity on the lab report.
Hardness and scaleScale in the kettle and geyser, soap that will not lather.Reported as hardness, calcium and magnesium. The SANS 241 limits table does not list a hardness limit.An ion-exchange water softener, which removes calcium and magnesium.A softener does not remove germs, and it does not make unsafe water safe. It tolerates only limited iron and manganese.Hardness, calcium and magnesium, plus iron and manganese.
Bad smellRotten egg smell (hydrogen sulphide).No SANS 241 health limit. The smell alone says little about whether the water is microbiologically safe.Aeration followed by filtration, an oxidising media filter (works up to about 6 mg/L), activated carbon for low levels (below about 1 mg/L), or continuous chlorination plus filtration.A sediment cartridge or a softener. If only the hot tap smells, the geyser can be the cause: the anode in a water heater can turn sulphate into hydrogen sulphide.Does the cold tap smell too? Test for E. coli as well. A fuel, solvent or sewage smell is a different matter: do not drink the water.
BacteriaNothing. Contaminated water can look and taste fine.E. coli: not detected in 100 mL (acute health). Total coliforms 10 per 100 mL and plate count 1,000 per mL (operational).UV disinfection on clear water, or chlorination with proper dosing and contact time. Boiling is a stopgap for drinking water, not a fix.Sediment filters, carbon, softeners and iron filters do not disinfect. A household RO unit should not be your germ barrier: the NSF/ANSI 58 claims list covers chemical reduction and cysts, with no bacteria or virus claim.E. coli on the lab report. Also check the borehole cap, seal and any sewage source nearby: treating the water does not fix a leaking wellhead.
High salts or TDSA salty or brackish taste.TDS 1,200 mg/L, conductivity 170 mS/m, sodium 200 mg/L, chloride 300 mg/L (all aesthetic, 2015 edition).Reverse osmosis (or distillation). RO removes sodium and chloride.Carbon, sediment cartridges, softeners and UV. RO also sends part of the water to drain as a reject stream, and it rejects a smaller share as the feed water gets saltier.TDS or conductivity, sodium, chloride and sulphate on the lab report.
NitrateNothing. It has no visible sign.Nitrate 11 mg/L as N (roughly 50 mg/L as nitrate) and nitrite 0.9 mg/L as N, both acute health.Reverse osmosis with a thin-film composite membrane (reduces nitrate by 60 to 95 percent), a nitrate-selective anion exchange resin, or distillation.Boiling raises nitrate, because water evaporates and the nitrate stays. Carbon, sediment filters and UV do not treat it, and a softener uses a different resin from nitrate exchange.Nitrate, nitrite, sulphate, TDS and hardness. A line-pressure RO unit needs feed pressure above 40 psi and nitrate no higher than 30 mg/L as N, and ion exchange is upset by high sulphate, TDS or hardness.
FluorideNothing. Children may show mottled teeth over time.Fluoride 1.5 mg/L (chronic health).Reverse osmosis (80 to 95 percent depending on the membrane), activated alumina (works best at pH 5.5 to 6.5), bone char, strong-base anion exchange or distillation.Standard carbon, sediment cartridges and UV. Activated alumina needs regenerating or exchanging. WHO notes that in some areas with naturally high fluoride, the guideline can be hard to reach with available technology.Fluoride and pH on the lab report. Siloam in Limpopo measured 3.92 to 4.95 mg/L, so some boreholes are far over the limit.
ArsenicNothing. Long-term exposure harms health.Arsenic 10 micrograms per litre (chronic health).WHO lists oxidation, coagulation and precipitation, adsorption, ion exchange and membrane techniques. This is specialist design. RO may reduce it, but NSF/ANSI 58 lists arsenic reduction and pentavalent arsenic reduction as separate claims, so the form of arsenic matters.Carbon, sediment cartridges, UV and softeners are not arsenic treatments. Do not buy on a general label: ask the supplier for evidence against your own result.Many standard packages leave arsenic out, so ask the lab for it. WHO's list of ways to cut exposure starts with substituting a high-arsenic source with a low-arsenic, microbiologically safe one.
Acidic waterCorrosion of metal pipes and fittings.pH 5 to 9.7 (operational).A calcite neutraliser, which is calcium carbonate media that reduces the corrosiveness of acidic water. A DWS review of one Table Mountain Group spring in Cape Town recorded pH below 6 and said low pH water that reacts with metal pipes can be corrected by adding lime.A neutraliser fixes pH. It does not remove germs, nitrate, fluoride or salts.pH, alkalinity and iron. Correct pH before an oxidising iron filter, which needs a workable pH range.

Percentages and ranges come from the WQA and extension sources listed below. Devices on the market differ widely in how well they treat a given contaminant, so the WQA advises choosing one only on validated test results for that contaminant, and checking the treated water afterwards.

The borehole filters in plain words

Sediment filter

Catches particles. The first stage and a cheap one, but it only treats what you can filter out.

Oxidising media filter

Turns dissolved iron, manganese and hydrogen sulphide into particles and traps them, then cleans itself by backwashing.

Water softener

An ion-exchange resin that swaps hardness minerals for something else. It is about scale, not safety.

Activated carbon

Good for taste, odour and many organic chemicals. It is not a treatment for nitrate, fluoride, arsenic, salts, hardness or germs.

UV steriliser

Disinfects clear water as it passes the lamp. See the limits below.

Chlorination

Chemical disinfection. It needs correct dosing and contact time, and the SANS 241 limit for free chlorine is 5 mg/L, so it is a specialist job.

Reverse osmosis (RO)

A membrane that holds back dissolved salts and many chemicals. See the limits below.

Two limits people miss: UV and RO

These two are sold as if they purify everything. Each does one job well and has real limits.

UV steriliser

  • It inactivates bacteria, viruses and parasites. CDC is clear that UV does not remove chemicals.
  • It only works if the light reaches the microbes. Higher turbidity lowers penetration, and a film or mineral deposit on the lamp or sleeve blocks the light, so supplier guidance places UV after the mechanical and other filters, with a small sediment filter in front.
  • Mineral build-up is how a sleeve gets coated, and one supplier lists feed iron below 0.3 ppm as a condition for its unit, so treat iron and hardness before UV.
  • Contact time falls as flow rises, so choose the unit by your maximum flow, not your average.
  • Suppliers list a lamp change every 12 months.

Reverse osmosis

  • It reduces dissolved salts and many chemicals: CDC lists chloride, sodium, lead, copper and chromium, and says it may also reduce arsenic, fluoride and sulphate.
  • Reduction is a percentage, not 100 percent: 60 to 95 percent for nitrate and 80 to 95 percent for fluoride in the WQA sheets, depending on the membrane. A very high result can still leave a result above the limit.
  • NSF/ANSI 58 claims cover total dissolved solids (required) and optional ones such as fluoride, nitrate, arsenic and cysts. There is no bacteria or virus claim in the list, so do not use a household RO unit as your germ barrier.
  • It sends a share of the water to drain as a reject stream, and it needs pre-filtration and adequate feed pressure. An under-sink unit treats one tap, not the house.

What a borehole water purification system really is

A "borehole water purification system" is not one device. It is a train of stages chosen for your lab result, and the order matters. A common arrangement is a sediment pre-filter first, then the stage that answers your main problem (iron filter, softener or pH neutraliser), then UV for germs, with a small RO unit at the kitchen tap if a dissolved chemical such as nitrate or fluoride is the issue.

Treat that as an outline, not a design. Ask any installer to show you which line of your lab report each stage answers, and to explain why it sits where it does. If a stage cannot be tied to a result, you may be paying for something you do not need. A packaged "complete" borehole system can still fall short: one supplier's own page says its sediment and iron system does not independently confirm the water as safe to drink.

Sizing a borehole filtration system

Sizing goes wrong when the filter is chosen first and the borehole second. Work in this order.

1. Start from what the borehole yields

A yield test tells you what the borehole can supply. A pump supplier's guide says to size the pump below the tested yield, so the flow reaching your filters is the pump's flow at your depth, not the pump's headline figure. See the borehole pump guide.

2. Match flow ratings in litres per hour

Supplier listings rate household media vessels at about 1,000 to 3,000 litres per hour, and UV units at 448 litres an hour (16 W), 1,360 (25 W) and 2,720 (55 W). Compare each to the peak flow at the point where it sits, usually after the tank and any booster pump.

3. Allow for backwash

Media filters clean themselves by backwashing at a high flow to drain. One supplier lists a backwash rate of 10 to 12 US gallons a minute per square foot of bed for a 10 inch vessel. Worked out from that, it is about 21 to 25 litres per minute (our calculation). Check the pump and tank can supply it for the whole cycle without drawing the borehole down.

4. Protect the stages that foul

Put the pre-filter in front of UV and RO. A line-pressure RO unit also needs adequate feed pressure (the WQA gives above 40 psi for nitrate reduction), and versions with a booster pump exist.

Ask your installer for three numbers in writing: the design flow, the pump's flow at your depth, and the backwash flow.

Looking after the system

  • Follow the schedule. Minnesota's health department says all treatment units need regular maintenance (changing filters, disinfecting the unit, backwashing, cleaning out scale), and that neglected units can make water quality worse.
  • Carbon does not disinfect itself. Wet carbon can grow bacteria if left idle. Flush after long periods without use and replace cartridges on schedule.
  • UV needs a new lamp every 12 months and a clean sleeve. Expect about R310 to R665 for the lamp.
  • Retest after installation and then regularly. The WQA says system performance should be checked by water analysis at installation and monitored periodically afterwards. See the maintenance guide and the water quality guide.

What borehole water filters cost

Indicative, from published prices on South African supplier sites, checked on 2 October 2026. These are supply prices for the equipment. We found no published installation prices we could rely on, so ask for an itemised quote that lists installation, plumbing and any pump or tank changes separately.

ItemIndicative supply priceNote
Sediment housing, 20 inch, with a 5 micron cartridge and bracketAbout R1,190Housing alone about R565. Replacement cartridges from about R150.
Iron and manganese filter, household size, automatic backwashAbout R9,400 to R24,000Complete vessel with media and backwash head, supply only.
Water softener, complete automatic systemAbout R9,000 to R18,200Complete system with resin and brine tank, supply only.
UV steriliser unitAbout R900 to R2,200For 448 to 2,720 litres per hour. A lamp costs about R310 to R665 a year.
Under-sink RO unit, 5 or 6 stageAbout R1,900 to R4,100Treats one tap. Versions with a booster pump cost more.

Many listings are on sale and prices change. For comparison, a SANS 241 laboratory test costs about R895 to R2,200 (see the safe-to-drink guide). Test before you spend on treatment.

Borehole filter questions

What is the best borehole water filter?

There is no best one in general, only the right one for your lab result. A filter for iron staining does nothing for nitrate, and a UV unit does nothing for fluoride. Get the test first, then choose stages to match the results, and test again after installation.

Is a sediment filter enough for borehole water?

Only if the water is merely cloudy or sandy and the lab result is otherwise clean. A sediment filter holds back particles, so dissolved iron, nitrate, fluoride, salts and germs go straight through.

Does a UV filter make borehole water safe to drink?

It deals with germs, and only when the water is clear enough for the light to reach them. It does not remove chemicals, so it will not touch nitrate, fluoride or arsenic. Iron and hardness can coat the lamp sleeve and block the light, so those are treated first.

Does reverse osmosis remove everything?

No. RO reduces many dissolved chemicals by a percentage, not by 100 percent, and the rate depends on the membrane and the water. It sends some water to drain, and the NSF/ANSI 58 standard for household RO lists no bacteria or virus claim, so do not count on one as a germ barrier. Pair it with disinfection if bacteria are a risk, and retest the treated water.

How much does a borehole filtration system cost?

It depends entirely on what the lab finds. Supply prices in the table above run from about R1,190 for a sediment housing to R9,400 or more for an iron filter, and installation is extra. One supplier lists a packaged sediment and iron system at R18,500 and says itself that it does not confirm the water is safe to drink. Ask for an itemised quote.

How often must I service a UV unit?

Suppliers list a lamp change every 12 months, plus cleaning of the quartz sleeve and replacement of the protective filter cartridge. A lamp that is still lit can be past its useful life, so keep to the schedule.

Start with a laboratory test

A SANS 241 report tells you which limits you exceed. Every treatment decision on this page follows from it.

Water testing guideRequest a quote

Sources