The updated SANS 241 (the South African National Standard for Drinking Water) marks a decisive shift from checklist compliance to system-wide risk management, requiring water providers to understand, monitor and actively control water quality from catchment to consumer.

Mariette Swart, water quality specialist at Rand Water, cautions that systems previously deemed compliant under SANS 241:2015 may no longer meet the requirements of SANS 241:2025. She was part of the South African Bureau of Standards (SABS) national committee – SABS/TC147, Water – that prepared the standard. “It is no longer sufficient to simply monitor a set of parameters, collect results, and compare them with the standard to demonstrate compliance.”

An integrated system

The new approach embraces an integrated system in which monitoring is only one element. In practice, compliance is demonstrating that the water supply system is understood, risks have been assessed, monitoring is targeted, and appropriate action is taken when results indicate a potential risk.”

Compliance is no longer viewed as a once-off or point-in-time result. Instead, SANS 241: 2025 requires an ongoing, system-specific risk assessment process to sit at the centre of drinking water quality management, continuously informing monitoring, operational decisions and risk mitigation measures.

SANS 241: 2015 consisted of two parts; the first stipulated the parameters and numerical limits for drinking water quality, while the second outlined the processes required to achieve compliance. “This created a fragmented approach where there was little integration between testing, reporting and risk management,” explains Swart.

SANS 241: 2025 replaces this with a single integrated framework, where numerical limits, risk assessments, monitoring programmes, verification, incident response and corrective actions are all linked within one system. This means compliance is no longer treated as a standalone laboratory result, but as the outcome of an ongoing, risk-based management process designed to demonstrate that water quality is being actively understood, monitored and controlled throughout the entire supply system.

Demonstrating compliance with the numerical limits prescribed in the standard is only one part of compliance; equal importance is placed on demonstrating that the systems, processes and controls required to manage drinking water quality are effective and fit for purpose. The standard therefore requires water providers to show that they understand the hazards and risks that could affect the quality of the water they supply, and that appropriate monitoring and management measures are in place to control these risks. As Swart notes, SANS 241:2025 is also explicit that insufficient monitoring data to demonstrate compliance is, in itself, an indication of non-compliance, reinforcing the principle that confidence in water quality depends not only on acceptable results, but also on adequate evidence that quality is being consistently managed and verified.

From catchment to tap

At the core of SANS 241 is the principle that drinking water must remain safe at the point of consumption. “A key misconception under SANS 241:2015 was that compliance could effectively be demonstrated at the treatment plant. In practice, this created a narrow focus on treated water leaving the works, rather than on the quality of water as it moves through reservoirs, pipelines and ultimately reaches the consumer,” explains Swart.

The new SANS 241 standard deliberately avoids using the terms water services provider and water services authority. “This is to move away from a siloed view of responsibilities. The standard is not intended to govern how different entities relate or contract with one another – that must be set out in separate agreements. Instead, SANS 241 focuses on the outcome: all parties involved in the supply chain share responsibility for ensuring that the water delivered to consumers is safe,” she adds.

Managing non-compliant parameters

Under the previous SANS 241:2015 framework, there was often inconsistency across the sector in how non-compliant results were handled. The revised standard now provides a clearer direction on what entities are expected to do once a water quality result falls outside the prescribed limits.

Clause 8: Management of drinking water quality non-compliant results recognises that a non-compliant result is not simply a laboratory issue or a reporting exercise. It must trigger an appropriate management response. The standard requires entities to investigate non-compliant results, assess the potential risk posed to consumers, determine the need for corrective actions, and verify whether the non-compliance indicates a broader water quality risk. The objective is not only to restore compliance, but also to understand the underlying cause of the non-compliance and prevent its recurrence.

It is also important to realise that non-compliant results cannot  be excluded from compliance reporting following a compliant re-sample. “The management clause links directly to the risk-based philosophy of the revised standard. A failed result is treated as evidence of a potentially unmanaged risk. The standard also emphasises that compliance can only be demonstrated where sufficient monitoring data is available. Where required monitoring information is unavailable, compliance cannot be confidently demonstrated and the associated risk remains unmanaged.,” says Swart.

In practice, the management clause requires entities to:

• investigate non-compliant results to determine the actual risk posed to consumers;
• assess the seriousness and urgency of the incident;
• implement corrective actions;
• conduct follow-up monitoring where necessary;
• document decisions and responses;
• communicate risks or advisories where public health may be affected; and
• demonstrate that the incident was properly controlled and managed.

Expanded and clarified microbiological requirements – key changes

Aspect	SANS 241: 2015	SANS 241: 2025
E. coli	Included	Still primary indicator
Intestinal enterococci	Not required	Mandatory only for saline/brackish systems
Protozoan parasites	Listed	More explicit turbidity linkage. Must be monitored at the final water, monthly.
Somatic coliphages	Included	Elevated role as viral indicator
Molecular methods (PCR)	Not addressed	Recognised (with limits)

Under SANS 241:2025, turbidity is treated as a critical operational risk parameter rather than just a compliance value. Elevated turbidity can reduce the effectiveness of disinfection and may indicate inadequate removal of particulate matter, creating conditions where microorganisms can be protected from disinfectants and increasing the risk of microbiological contamination. Swart emphasises that turbidity, together with residual disinfectant and pH, are among the most important operational control parameters at a treatment works.

“These are rapid, instrument-based measurements that provide immediate feedback on whether treatment processes are functioning as intended. Frequent monitoring allows operators to identify process deterioration early and take corrective action before water quality is compromised. Without reliable turbidity data, it becomes difficult to demonstrate that treatment barriers are consistently performing as required.”

Under the previous edition of SANS 241, turbidity was regulated through both aesthetic and operational limits, with 5 NTU considered acceptable for aesthetic purposes and 1 NTU serving as the operational limit. SANS 241:2025 now requires turbidity to remain below 1 NTU, reinforcing its role as a key indicator of treatment performance. Results exceeding 1 NTU constitute a non-compliance that must be investigated and managed in accordance with the requirements of the standard.

“Municipalities should not simply aim to achieve compliance at 1 NTU” says Swart. Good practice is to maintain final water turbidity well below the limit, typically around 0.5 NTU or lower, to provide an operational safety margin and reduce the likelihood of non-compliant results.”

The revised standard also strengthens the link between protozoan parasite risk and turbidity performance. Protozoan parasites are included as mandatory process risk parameters, and their monitoring forms part of the routine monitoring programme. SANS 241:2025 recognises that consistently low turbidity, monitored at an appropriately high frequency and supported by documented process control, provides important operational evidence that treatment processes are functioning effectively and reducing the likelihood of protozoan breakthrough. However, turbidity monitoring does not replace the requirement to manage and verify protozoan risk; rather, it serves as an important operational indicator of treatment performance and process control.

Parameters most likely to trigger non compliances

Mariette Swart notes that failures relating to disinfectant residuals are expected to become one of the most common reasons why systems may fail compliance under SANS 241:2025.

The minimum residual disinfectant requirement is now clearly defined. For systems using chlorine as the disinfectant, water leaving the treatment plant should maintain a minimum free chlorine residual of 0.5 mg/ℓ, while a minimum residual of 0.1 mg/ℓ should be maintained throughout the distribution network. These minimum values are intended to ensure that disinfectant protection remains active throughout the reticulation system, particularly where there is a risk of recontamination, long retention times, or chlorine decay.

There is also a tighter limit to aluminium, which has been reduced from 300 µg/ℓ to 200 µg/ℓ. The parameter is no longer viewed purely as an aesthetic concern, but also as an important indicator of treatment performance.  Elevated aluminium concentrations in final water may indicate inadequate optimisation of coagulation, flocculation, clarification or filtration processes, particularly where aluminium-based coagulants are used, although aluminium concentrations may also be influenced by source water quality. The stricter limit is therefore expected to place greater emphasis on process optimisation, including coagulant dosing, pH control and sludge management, to ensure consistent compliance.

Similarly, ammonia is considered an operational parameter because it provides information on the effectiveness of disinfection processes and the stability of disinfectant residuals. In chloraminated systems, ammonia monitoring is particularly important for controlling chloramine formation and preventing nitrification within the distribution network.

The cost

“Knowing your system will ultimately reduce the cost of monitoring. I cannot over emphasize the importance of knowing what parameters must be tested, why they are being tested, where they should be tested and when they should be tested,” adds Swart.

The revised standard is ultimately designed to support more targeted and cost-effective monitoring. Instead of routinely testing every possible parameter, the risk-based approach focuses resources on the parameters that pose a credible risk to a specific supply system.

This means that entities with a strong understanding of their systems and good historical data may not see a significant increase in monitoring costs over the long term. In some cases, costs could even decrease as unnecessary or repetitive testing is reduced. However, systems with limited data, weak monitoring programmes or poor operational control may initially face increased expenditure as additional sampling, risk assessments and monitoring programmes are implemented to close information gaps.

The revised standard also recognises South Africa’s practical constraints, including limited laboratory capacity and municipal budget pressures. As a result, the technical committee attempted to balance public health protection with what is realistically achievable on the ground. Expensive analyses for contaminants such as protozoan parasites or emerging organic compounds are therefore approached through a risk-based lens, with entities expected to prioritise monitoring where there is a credible likelihood of contamination rather than applying blanket testing requirements across all systems.

Importantly, the standard shifts the conversation around cost from one of simple compliance to one of risk prevention. Poorly targeted monitoring programmes that fail to identify emerging problems can ultimately become far more expensive through operational failures, water quality incidents, emergency interventions and reputational damage.

The intention of the revised framework is therefore not necessarily to increase testing, but to ensure that monitoring programmes are defensible, relevant and capable of protecting public health. Ultimately, the revised SANS 241 reflects a more mature approach to water quality management.

Important terms, definitions and clauses

Definitions and key clauses determine how requirements are interpreted, applied and enforced across different types of supply systems. “The definitions are explained once at the start of the standard and, thereafter, the document only refers back to those terms, on the assumption that you already understand what each definition means,” explains Swart.

A water supply system (WSS): is an asset system that includes the raw water abstraction point, the water treatment plant (WTP) up to the final water, and the distribution network up to the point of delivery to consumers. Within the same supply area, water quality can vary due to factors such as geographical location, infrastructure age, distance from the WTP, supply from multiple WTPs, or a combination of these. Each distinct water quality zone should therefore be managed as a separate WSS, with distribution network sample points selected to accurately represent each system.

A borehole system: is an asset system that utilises groundwater of low water quality variability, where disinfection is practised, serving a maximum population of 5 000 people. Sampling points in a borehole system include the final water and a limited number of distribution network sample points. Systems that utilise groundwater where water quality varies, or serve populations exceeding 5 000 people, should meet the requirements for a water supply system.

Raw water: untreated surface water, groundwater, or water effluent entering a WTP for treatment.

• Final water: drinking water after treatment supplied from the WTP.
• Distribution network sample point: sample point within the distribution network after the final water where water quality is monitored to ensure complete representation of the entire geographical distribution network and weighted according to population density. A distribution network sample point can be a reservoir, a dead end, a point of delivery, points of consumption such as a high occupancy building, a hospital, or a school.
• Critical distribution network sample point: subset comprising 20% of the distribution network sample points that provide the most information on spatial and temporal risks and where a noticeable deterioration in water quality or increased risk is anticipated. Critical distribution network sample points can include reservoirs, dead-ends, points of delivery, points of consumption such as high occupancy buildings, hospitals, or schools. During the risk analysis, critical distribution network sample points in supply systems are analysed for all the parameters listed in table 2. Monitoring of confirmed risks will continue at the critical distribution network sample points as part of the routine monitoring programme.