Water Supply Infrastructure And Reliability - Definitions And Information

This brief sets out information relating to water supply infrastructure and the reliability of service.
Water Supply Infrastructure And Reliability - Definitions And Information


From a policy point of view, it is desirable to know the extent to which water supply is adequate and where it requires development. Where water supply is adequate, the issues are those of maintenance and operation to ensure that water supply interruptions are minimised and that the quality of water does not endanger health. Where development is needed, capital expenditure is required, the nature and extent of which will depend on context.

Rational policy requires an information system. There is no system which furnishes all the relevant information, but there are four data sources which supply some of it. They are:

  1. The Department of Water and Sanitation’s (DWS) National Water Services Knowledge System (WSKS)
  2. The DWS’s National Integrated Water Information System (NIWIS)
  3. The DWS’s Integrated Regulatory Information System (IRIS)
  4. Statistics South Africa’s Community Survey 2016

The relevant information in each source is summarized in the Appendix.

The basic and RDP water standards

Adequacy of water supply is a normative issue. One may approach it by considering government specifications[1].

The basic water standard has the following components:

  1. A minimum volume of 6 000 litres (or 25 litre per person per day) of potable water shall be made available to a household per month.
  2. The water provided shall comply with the SANS 241 quality standards.
  3. The access/delivery point shall be at least a yard connection.
  4. The water shall be made available for at least 350 days per year, and not interrupted for longer than 48 consecutive hours.

Requirement 3 of at least a yard connection is relatively new. The older standard was that the source should be piped water within 200 metres of the dwelling. The new standard is referred to here as the ‘basic standard’ and the older standard will be called the ‘RDP standard’. Existing measurement still uses the RDP standard.

This specification needs unpacking, and some parts of it are unclear, especially when it comes to the type of supply and identity of the supplier. For instance, what is a yard connection? It may often be to a municipal water supply. But does the definition extend to connection to community water schemes, or own sources on the property, such as boreholes and rain water tanks? Further issues arise when the access standard is that water should be available within 200 metres of the dwelling. Here piped water to a community stand would be eligible, but this could be supplied by a municipality or a community water scheme. Is access to a neighbour’s tap within 200 metres adequate?

Similarly, the SANS 241 requirements are complex. It identifies three categories of risk:

  1. Health risks, where water quality may cause acute or chronic health problems in individuals. 
  2. Aesthetic risks, where water is visually, aromatically or palatably unacceptable.
  3. Operational risks, where water quality indicates that operational procedures to ensure water quality standards are met may have failed.

Water consumers are likely to perceive the quality of water supply as poor on aesthetic grounds, or whether consumption causes acute health problems. But some health risks are undetectable by consumers, and not all aesthetic risks are health risks. Operational risks are essentially diagnostic for suppliers of water through treatment plans, and they indicate a need for attention to operational procedures.

Health risks can be divided into the following subcategories:

  1. Microbiological risks. These are indicated by the presence of E. coli and faecal and other coliforms as well as parasites (cytosporidium and giardia)
  2. Disinfectant residual risks. Key disinfectants are chlorine and monochloramine. In appropriate concentrations they help disinfect water, but beyond a certain level, they pose a health risk.
  3. Chemical risks. Upper limits are specified for a range of chemicals: nitrates, nitrites, fluoride, antimony, arsenic, barium, boron, cadmium, chromium, cobalt, copper, cyanide, iron, lead, manganese, mercury, nickel, selenium, uranium, vanadium, aluminium, and carbon, as well as for some organic chemicals

Aesthetic risks include colour, total dissolved solids, turbidity, pH (acidity or alkalinity), sulphates, ammonia, chloride, sodium, zinc, iron, manganese and phenols. Operational problems are indicated by turbidity, pH and a high concentration of aluminium.

Charles Simkins
Head of Research

Appendix – Information on water infrastructure and reliability

In all cases, the household rather than the individual is regarded as the consumption entity.

The dates for which items of information are indicated in square brackets.

1. The Water Services Knowledge System.

WSKS provides tables of the following variables by Water Service Authority:

  • Households with no access to water [April 2018]
  • Households below the RDP infrastructure standard [April 2018]
  • Households with water reliability problems [April 2018]
  • Households by water service levels (known as ‘water sources’ by the Community Survey). [April 2018]

2. The National Integrated Water Information System.

NIWIS provides tables of the following variables by Water Service Authority:

  • Households with access to water infrastructure, divided into urban and rural [March 2019]
  • Households with a reliable water supply, divided into urban and rural [March 2019]
  • Drinking water quality compliance [Year ending 31 January 2019]

3. The Integrated Regulatory Information System

IRIS provides data on water quality at a number of points within each Water Service Authority

4. The Community Survey 2016

The following variables are reported within the household file:

  • Rating of water quality service
  • Water source
  • Distance to water sources
  • Access to safe drinking water service
  • Water supplier
  • Whether there has been an interruption in municipal supply in the last three months, excluding scheduled water shedding and interrupted water supply as a result of non-payment. If so, what has been the aggregate period of interruption, has there been an interruption of more than two consecutive days, and what alternative water source was used during the interruption.
  • Main dwelling type
  • Municipality
  • Geographical type (urban, traditional or farm)

[1] The most recent specification of standards is contained in Department of Water Affairs, National Water Act (36/1998): National Norms and Standards for Domestic Water and Sanitation Service, Government Gazette 41100, 8 September 2017