Is Tap Water Safe to Drink in South Africa? What the Blue Drop Data Shows and What Home Filters Remove

What is the Blue Drop report?

Blue Drop is DWS’s regulation programme for municipal drinking water. Each water supply system (the treatment works, pipes and reservoirs that serve a town or part of a city) is audited and given a Blue Drop score out of 100. The score reflects how well the system is run, from water quality monitoring to treatment and staffing. Systems scoring above 95% qualify for Blue Drop certification, and DWS classes systems scoring below 31% as being in a critical state (DWS, Blue Drop Report 2023).

Separately, DWS gives each system a Blue Drop Risk Rating. This works the other way round: a higher percentage means a higher risk.

Full audits of every system are published as a full report; the latest came out in December 2023. In between, DWS publishes shorter progress assessments. The most recent was released on 31 March 2026, and the next full report is due in 2027 (PMG, 9 June 2026).

What did the latest Blue Drop reports find?

The 2023 full report

DWS assessed all 958 water supply systems run by 144 water services authorities (the municipalities responsible for water) (DWS media statement, 5 Dec 2023). Its main findings:

• Microbiological quality. Based on municipalities’ own tests in 2021/22, 54% of systems had excellent or good microbiological compliance and 46% had poor or bad compliance. In 2014 the poor-or-bad figure was 5%.
• Critical systems. 277 systems (29%), in 62 municipalities, were in a critical state, up from 174 systems in 33 municipalities in 2014.
• Certification. 26 systems scored above 95% and earned Blue Drop certification, against 44 in 2014.
• Metros. DWS stated that “drinking water systems in the major metropolitan areas are generally performing well.”

Those percentages count systems, not people. A small town’s system and a metro’s system each count as one, so the 46% figure does not mean that 46% of South Africans drink water of poor quality.

The 2025 progress assessment

The 2025 assessment covered 1,006 systems in all 144 water services authorities, using data from July 2023 to June 2024. It was a limited, risk-based check rather than a full audit (DWS presentation, 9 June 2026).

Blue Drop Risk Rating	Systems in 2025	Share in 2025	Share in 2023
Low (below 50%)	622	62%	60%
Medium (50% to under 70%)	199	20%	19%
High (70% to under 90%)	106	10%	11%
Critical (90% to 100%)	79	8%	10%

Source: DWS presentation to the Portfolio Committee on Water and Sanitation, 9 June 2026. The four groups add up to 1,006 systems. Shares are as DWS rounded them (106 of 1,006 is 10.5%).

DWS described the risk picture as having “stabilised, albeit at a high level” since 2023 and again said metro systems were generally performing well. By province, the Western Cape had the lowest average risk rating (31%), followed by Gauteng (35%) and North West (36%), and Gauteng and the Western Cape had no systems in the critical band. The Northern Cape had the highest average risk rating (68%), and the Free State, Limpopo and Northern Cape each had more than 10% of their systems in the critical band.

What is SANS 241?

SANS 241 is the South African National Standard for drinking water, published by the South African Bureau of Standards (SABS). The current edition, SANS 241:2015, sets limits for microbiological, physical, aesthetic and chemical properties of water. Water that meets it is considered an acceptable health risk for a lifetime of drinking, which the standard defines as 2 litres a day for 70 years by a 60 kg person. The standard is sold by SABS rather than published free; the limits below are the ones in the 2015 edition and are unchanged in the 2024 public draft of the next edition (linked below).

The standard groups its limits by the kind of risk:

• Acute health: things that can make you ill quickly. The best known is E. coli, which must not be detected in a 100 ml sample.
• Chronic health: things that matter over years of drinking, such as lead and arsenic (both limited to 10 micrograms per litre) and fluoride (1.5 mg per litre). These match the World Health Organization’s guideline values for the same substances (provisional ones, for lead and arsenic) (WHO, lead; arsenic; fluoride).
• Aesthetic: taste, smell and colour.
• Operational: measures that show whether treatment is working, such as turbidity (cloudiness).

A municipality’s results are graded by the share of samples that meet these limits. On DWS’s water quality dashboard, for example, a system’s microbiological results are rated excellent above 99% compliance, good from 97% to 99%, poor from 95% to 97% and bad below 95% (DWS IRIS Potable Overview).

A revised edition went out as a draft for public comment in July 2024 (draft SANS 241, edition 7); DWS’s dashboards still measure results against the 2015 edition.

How do you check your own municipality’s water quality?

1. Use DWS’s My Water page. Go to ws.dws.gov.za/IRIS/mywater.aspx, type your town or suburb into the “Search By” box and click Go. The results show your municipality, the supply system that serves the area and the sites where samples are taken. The map rates systems as excellent, acceptable, poor or bad, using microbiological results from the past three months and other results from the past year, measured against SANS 241:2015. If the map doesn’t load (it didn’t when we checked in early November 2026), the search results still tell you which supply system you are on. Check the municipality named above each result, because a search can also return places with similar names in other provinces.

2. Look at the Potable Overview dashboard. On the same site, the Dashboards menu has a “Potable Overview” page with this year’s compliance figures, split into microbiological, chemical, operational and disinfectant results.

3. Read your municipality’s own reports. Many municipalities publish water quality results. The City of Cape Town, for example, posts quarterly figures and an annual report (City of Cape Town, Water quality). If yours doesn’t, ask its water department for the latest SANS 241 results for your supply system.

4. Check the Blue Drop report. The 2023 full report is arranged by province, with a section for each water services authority, and DWS says it includes data on the performance of each supply system (DWS, Blue Drop Report 2023). It runs to more than 500 pages, so use the contents list to find your municipality.

Is tap water safe to drink in South Africa’s main cities?

• Cape Town. The City reports compliance of between 99.0% and 99.6% in every quarter from July 2021 to June 2025 (City of Cape Town). Its metro supply system earned Blue Drop certification in 2023 (Western Cape Government, 7 Dec 2023), and its 2025 annual report states that the water is “tested, treated and safe to drink” (City of Cape Town annual report, 2024/25).
• Johannesburg, Tshwane and Ekurhuleni. No Gauteng system was in the critical-risk band in the 2025 assessment, and DWS says metro systems generally perform well. Gauteng’s recurring problem is supply interruptions, which DWS linked in 2023 to demand sometimes exceeding the supply of treated water (DWS, 5 Dec 2023). The next section covers what to do when the water comes back.

Even a well-run system can issue a local boil-water notice, and a notice takes priority over any annual figure.

What should you do after an outage or a boil-water notice?

When water comes back after an interruption

The City of Cape Town’s advice after restoring supply is that water may look discoloured at first, which is normal: let it run until it is clear, and trapped air in the pipes will clear as the water flows (City of Cape Town, 10 July 2025). Use the first, discoloured water for flushing toilets or watering the garden.

When there is a boil-water notice

• Boil it. The World Health Organization says bringing water to a rolling boil is enough to kill or inactivate disease-causing bacteria, viruses and protozoa (WHO, 2015). The City of Cape Town’s notices ask residents to boil tap water for one minute and let it cool naturally (City of Cape Town, 8 March 2023). The US Centers for Disease Control and Prevention (CDC) also advises one minute at a rolling boil, or three minutes above about 2,000 m (CDC).
• Or use bleach. If you can’t boil, the City of Cape Town advises mixing 1 teaspoon (5 ml) of unperfumed household bleach into 20 to 25 litres of water and letting it stand for at least two hours before use (same notice).
• Cloudy water first. If the water is cloudy, the CDC suggests filtering it through a clean cloth, paper towel or coffee filter, or letting it settle and drawing off the clear water, before you treat it.
• Store it clean. Keep treated water in clean, covered containers.

The City of Cape Town’s notice covers water for drinking and for washing fruit and vegetables eaten raw; the CDC adds cooking and personal hygiene. Keep going until your municipality lifts the notice.

Boiling does not remove chemicals. The CDC states that water containing fuel, toxic chemicals or radioactive material cannot be made safe by boiling or disinfecting it. If the problem is chemical, follow your municipality’s instructions.

Babies, pregnancy and weakened immunity. If you are pregnant, are preparing formula for a baby, or you or someone in your home has a weakened immune system, ask your doctor or clinic how to handle drinking water, both under a notice and in general.

What do home water filters remove?

A home filter only removes what it is designed and certified to remove. Common certifications for household systems come from NSF, an independent standards and certification organisation, and each covers a different job. NSF itself says that certification “does not mean that a filter, purifier or treatment system will reduce all possible contaminants” (NSF). Before buying, check which standards and which specific contaminants the maker’s certificate lists.

Treatment	What it does	Relevant certification	What it doesn’t do
Sediment filter	Traps sand, rust and silt; usually the first stage in a larger system	NSF/ANSI 42 (nominal particulate reduction)	Doesn’t remove dissolved chemicals, taste or smell, and isn’t a disinfection step
Activated carbon (jug, tap or under-sink)	Reduces chlorine taste and smell	NSF/ANSI 42 (aesthetic); some carbon filters are also certified to NSF/ANSI 53 for named health-related contaminants	Not a disinfection step unless certified for microbes; reduces only the contaminants on its listing
Reverse osmosis (RO)	Forces water through a semi-permeable membrane, reducing many dissolved substances	NSF/ANSI 58; NSF/ANSI 401 for systems verified against named “emerging contaminants”	Sends part of the water to the drain (see below); the membrane and pre-filters need regular replacement
Ultraviolet (UV)	Inactivates microbes as water passes a UV lamp	NSF/ANSI 55: Class A for bacteria, viruses and cysts in contaminated water; Class B only for non-disease bacteria in water that is already disinfected	Removes nothing: no chemicals, no sediment, no taste. Light has to reach the microbes, so cloudy water needs pre-filtering
Ceramic or gravity filter	Strains particles and microbes through fine pores; some gravity units add a carbon stage	NSF/ANSI 42 or 53 depending on the claim; for parasites such as Cryptosporidium, the CDC advises a filter certified to NSF/ANSI 53 or 58 for cyst reduction or removal	The CDC notes that portable filters don’t remove viruses; bacteria removal needs an absolute pore size of 0.3 microns or smaller
Distillation	Boils water and collects the condensed steam	NSF/ANSI 62	NSF notes that some volatile organic chemicals can carry over with the steam; needs heat, so it uses energy

Sources: NSF, Standards for Water Treatment Systems; particulate-reduction claims from NSF’s NSF/ANSI 42 listings; cyst reduction from CDC, About Choosing Home Water Filters; pore sizes and viruses from CDC.

How to read a filter’s claims

• Look for the standard number and the contaminant. A certificate naming a standard and the contaminants it covers can be checked. “Removes 99% of impurities” can’t.
• Match the filter to the problem. If your tap water tastes of chlorine but passes SANS 241, a carbon filter certified to NSF/ANSI 42 addresses the taste. If you want a system for microbial reduction, look for NSF/ANSI 55 Class A UV or a filter certified for cyst or microbial reduction, and still follow any boil-water notice. If your concern is dissolved salts in borehole water, look at RO.

What a filter can’t fix

• The wrong filter for the problem. A carbon jug won’t disinfect water under a boil-water notice, and a UV lamp won’t remove a chemical. During a notice, boil or treat the water as the notice says, whatever filter you have.
• Skipped maintenance. A cartridge’s claims apply within the capacity the maker states, in litres or months. UV lamps, RO membranes and pre-filters all have replacement schedules. Keep a note of when each part was last changed.
• Water wasted by RO. The US Environmental Protection Agency says a typical point-of-use RO system sends 5 litres or more to the drain for every litre of treated water it produces, and some send up to 10. Systems carrying the EPA’s WaterSense label send no more than 2.3 litres per litre (US EPA WaterSense).

Is borehole water safe to drink?

Don’t assume it is. Borehole and wellpoint water isn’t treated by the municipality and is not covered by your municipality’s SANS 241 monitoring. A WWF guide published on the Western Cape Government’s website advises assuming that borehole and wellpoint water in Cape Town needs treatment before drinking, notes that local groundwater can carry high iron or salt or microbes from leaking sewage systems, and says the only way to know whether it is safe to drink is a test at a registered laboratory against SANS 241 (WWF Water File, 2018).

To test it, use a laboratory accredited by the South African National Accreditation System (SANAS), whose website has a search for accredited facilities (SANAS). Ask for a test against SANS 241 that covers microbiological and chemical results, and retest if the taste, smell or colour changes. Once you know what’s in the water, you can choose treatment that targets it.

Frequently asked questions

Is Cape Town tap water safe to drink?

The City reports 99.0% to 99.6% compliance with SANS 241 in every quarter from July 2021 to June 2025, and its metro system was Blue Drop certified in 2023. Follow any local boil-water notice.

Is Johannesburg tap water safe to drink?

DWS says metro systems generally perform well, and no Gauteng system was in the critical-risk band in the 2025 assessment. Check your own supply system on My Water.

Does boiling make tap water safe?

Boiling kills or inactivates disease-causing bacteria, viruses and protozoa, which is why WHO recommends bringing water to a rolling boil. It doesn’t remove chemicals, metals or salts.

How much bleach do you add to purify water?

The City of Cape Town advises 1 teaspoon (5 ml) of unperfumed household bleach in 20 to 25 litres of water, left to stand for at least two hours. Use bleach only if you can’t boil the water, and follow your own municipality’s notice if it differs.

Does a jug filter make tap water safe to drink?

Jug filters are usually activated carbon, aimed at chlorine taste and smell. A jug filter isn’t a substitute for boiling during a notice.

Why does my tap water smell of chlorine?

Municipalities disinfect drinking water, often with chlorine, and the DWS dashboard tracks disinfectant results as a separate category. SANS 241 allows up to 5 mg per litre of free chlorine. A carbon filter certified to NSF/ANSI 42 reduces the taste and smell.

Why is my water brown after an outage?

The City of Cape Town says discoloured water after supply is restored is normal, that trapped air clears as the water flows, and advises letting the tap run until the water is clear.

Do I need a water filter in South Africa?

Not necessarily. If your supply system’s results are good and you’re happy with the taste, there’s no need. A filter makes sense for a specific problem, such as chlorine taste or borehole water, when it is certified for that problem.

Sources

All opened and checked on 2 Nov 2026 unless noted.

1. Department of Water and Sanitation. “Release of the Full Blue and No Drop Reports, and the Green Drop Progress Assessment Report.” Media statement, 5 Dec 2023. https://www.gov.za/node/825720
2. Department of Water and Sanitation. “Water and Sanitation releases 2023 full Blue Drop Report.” Media statement, 5 Dec 2023. https://www.gov.za/news/media-statements/water-and-sanitation-releases-2023-full-blue-drop-report-05-dec-2023
3. Department of Water and Sanitation. Blue Drop Report 2023 (national report), copy hosted by Ugu District Municipality. https://ugu.gov.za/wp-content/uploads/2024/09/BDN_2023_Report.pdf (only the opening sections, to p. 16, could be read through web fetch: score bands, risk-rating bands and the contents list with a section per water services authority)
4. Department of Water and Sanitation. “Water Services Drop Programmes: overall findings,” presentation to the Portfolio Committee on Water and Sanitation, 9 June 2026 (includes the 2025 Blue Drop progress assessment). https://static.pmg.org.za/260609_GD_BD_ND_overall_findings_PC_9_June_26.pdf
5. Parliamentary Monitoring Group. “Green, Blue and No Drop Reports 2025: Ministry briefing,” 9 June 2026. https://pmg.org.za/committee-meeting/43264/
6. Department of Water and Sanitation, IRIS. “My Water.” https://ws.dws.gov.za/IRIS/mywater.aspx (opened in a browser; map panel did not load)
7. Department of Water and Sanitation, IRIS. “Potable Overview” dashboard. https://ws.dws.gov.za/IRIS/dashboard_status.aspx (opened in a browser)
8. SABS. SANS 241-1:2015 Drinking water, Part 1: Microbiological, physical, aesthetic and chemical determinands, edition 2, and SANS 241-2:2015. Paid standard; read from an unofficial copy found online, not linked. The limits quoted in the article were cross-checked against the official public draft (source 9) and WHO guideline values (sources 23 to 25).
9. SABS. Draft SANS 241 edition 7 (public enquiry draft, circulated 11 July 2024, comments closed 11 Sept 2024), copy hosted by Umgeni-uThukela Water. https://umgeni.co.za/wp-content/uploads/2024/07/SANS241ED7_TC147_DSS_2.pdf
10. City of Cape Town. “Water quality” (quarterly compliance table). https://www.capetown.gov.za/Work%20and%20business/Commercial-utility-services/Commercial-water-and-sanitation-services/Water-quality
11. City of Cape Town. Annual Drinking Water Quality Report, July 2024 to June 2025. https://www.capetown.gov.za/_documents/resource.capetown.gov.za/documentcentre/Documents/City%20research%20reports%20and%20review/Annual_Tap_Water_Quality_Analysis_2025_English.pdf
12. Western Cape Government (MEC Anton Bredell). “Western Cape municipalities making progress with safe drinking water,” 7 Dec 2023. https://www.gov.za/news/media-statements/mec-anton-bredell-western-cape-municipalities-progress-safe-drinking-water
13. City of Cape Town. “Precautionary notice: residents of the deep south advised to boil water before drinking,” 8 March 2023. https://www.capetown.gov.za/Media-and-news/PRECAUTIONARY%20NOTICE%20Residents%20of%20the%20deep%20south%20advised%20to%20boil%20water%20before%20drinking
14. City of Cape Town. “Water restored in Khayelitsha,” 10 July 2025. https://www.capetown.gov.za/Media-and-news/Water%20restored%20in%20Khayelitsha
15. World Health Organization. Boil water (technical brief WHO/FWC/WSH/15.02), 14 Jan 2015. https://www.who.int/publications/i/item/WHO-FWC-WSH-15.02 (publication page read; the PDF itself would not open)
16. US Centers for Disease Control and Prevention. “How to Make Water Safe in an Emergency.” https://www.cdc.gov/water-emergency/about/
17. NSF. “NSF Standards for Water Treatment Systems.” https://www.nsf.org/knowledge-library/standards-water-treatment-systems
18. US Centers for Disease Control and Prevention. “About Choosing Home Water Filters.” https://www.cdc.gov/parasites/crypto/gen_info/filters.html
19. US Environmental Protection Agency, WaterSense. “Point-of-Use Reverse Osmosis Systems.” https://www.epa.gov/watersense/point-use-reverse-osmosis-systems
20. WWF South Africa. “How to secure safe drinking water,” Wednesday Water File #3, 31 Jan 2018, hosted by the Western Cape Government. https://www.westerncape.gov.za/110green/files/atoms/files/WWFWaterFile_%233drinking_water.pdf
21. South African National Accreditation System (SANAS). https://www.sanas.co.za/
22. NSF. Certified product listings, NSF/ANSI 42 (claim names incl. “Nominal Particulate Reduction”). https://info.nsf.org/Certified/dwtu/listings.asp?Standard=042
23. World Health Organization. Lead in drinking-water chemical fact sheet, 2022 (provisional guideline value 10 µg/L). https://cdn.who.int/media/docs/default-source/wash-documents/water-safety-and-quality/chemical-fact-sheets-2022/lead-fact-sheet-2022.pdf
24. World Health Organization. “Arsenic” fact sheet (provisional guideline value 10 µg/L). https://www.who.int/news-room/fact-sheets/detail/arsenic
25. World Health Organization. Fluoride chemical fact sheet (guideline value 1.5 mg/L). https://www.who.int/docs/default-source/wash-documents/wash-chemicals/fluoride-chemical-fact-sheet.pdf