Background
Methods
Data sources
Statistical analysis
Trends in perceived drinking water safety
Modelling perception of drinking water safety
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Water taste, colour and odour: Previous studies of bottled water use by consumers in developed countries have found such organoleptic water characteristics to be important [27], whilst in India, rural respondents cited clarity, lack of odours, and an unsalty taste as being characteristics of safe water [21].
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Water supply type: Water supply type provides contextual grounds for households to assess drinking water safety, as evidenced by respondents reported in Banda et al. (2007) who considered boreholes to be associated with safe water. We therefore distinguished piped supplies from boreholes, rainwater and tanked water, and surface waters, springs and wells by grouping together the relevant GHS source types. Since perceived control of supply systems has sometimes also been associated with water safety [28], we further distinguished public / communal taps and neighbours’ taps from piped water on a household’s premises.
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Water interruptions: These provide a further contextual indicator of drinking water safety and there is some evidence from South Africa that dissatisfaction with supply interruptions could extend to other aspects of service delivery such as water quality [29].
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Information deprivation: Since there is some evidence that complaints to South African water providers increase in response to media coverage of the water sector [18], we examined information access in shaping perceptions of drinking water safety. Gordon et al. [30] have developed a composite measure of information deprivation, which is based on access to newspapers, radio, television, and telephone, and we used a similar metric here, counting the number of such information sources a household had access to.
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Residence in a cholera-affected province: The South African government initiated public health campaigns to promote home water treatment in cholera-affected areas [31], which may have raised awareness of unsafe drinking water. We therefore examined residence in a cholera-affected province as a possible influence on perceived drinking water safety. Over 97% of the 17,902 cholera cases reported between August 2001 and July 2002 (the date of the GHS) were in KwaZulu-Natal and Eastern Cape Provinces [32], so we generated a dummy variable to represent these provinces. Although a cholera outbreak also took place in 2008 centred on Limpopo and Mpumulanga Provinces, cases were only reported in November and December, after the GHS took place in July [33]. We therefore did not use a provincial dummy variable in this year.
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Household expenditure: As a measure of socio-economic status, we focused on household expenditure rather than income, since such measures are much more reliable and are easier to collect than income, especially in most rural settings [34].
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Ethnicity, educational level, and gender of household head: Ethnicity was considered fundamental by Maharaj and Pietersen [35] when consulting South Africa’s population over water sector policy, whilst Anderson et al. [9] found attitudes to water pollution varied between African and other ethnic groups in South Africa. Pradhan [36] describes the proportion of households linking contaminated water with disease as varying by educational level and gender, independent of ethnicity.
Result
Trends in public perceptions of drinking water safety
Factors influencing perceived drinking water safety
Percentage of households (observations unweighted to adjust for sample design) | ||
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2002 | 2008 | |
No. households | 26,243 | 24,222 |
Variable | ||
Water supply characteristics | ||
Water free from odours | 88.85 | 91.08 |
Water clear | 90.52 | 91.29 |
Water tastes good | 89.22 | 90.72 |
Private piped supply | 67.56 | 70.46 |
Public or communal taps / neighbour’s piped supply | 16.19 | 18.09 |
Borehole | 4.41 | 3.14 |
Rainwater or water carrier | 1.24 | 1.54 |
Other sources (e.g. river, stream, dam, well, spring) | 10.54 | 6.43 |
Supply interruptions | ||
Daily | 2.50 | 3.79 |
Weekly | 5.45 | 8.08 |
Monthly | 8.72 | 11.22 |
6-monthly | 8.62 | 8.35 |
Yearly | 3.80 | 4.17 |
Almost never | 54.03 | 37.87 |
Household characteristics | ||
Household head male | 62.18 | 60.90 |
Household head ethnic group: | ||
Black African | 77.12 | 76.47 |
Coloured | 7.91 | 8.29 |
Indian or Asian | 2.40 | 2.63 |
White | 12.57 | 12.61 |
Household head educational level | ||
No education | 16.16 | 14.17 |
Attended primary education | 28.70 | 24.43 |
Attended secondary education or higher | 53.73 | 55.12 |
Household monthly expenditure (South African Rand) | ||
< 400 | 31.29 | 9.38 |
400 – 799 | 27.17 | 23.13 |
800 – 1199 | 11.94 | 19.12 |
1200 – 1800 | 7.08 | 12.42 |
1800 – 2500 | 5.54 | 8.57 |
2500 – 5000 | 7.17 | 11.44 |
5000 – 10000 | 4.69 | 7.99 |
>10000 | 1.66 | 5.33 |
Characteristic | 2008 | 2002 | ||||
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Odds ratio | T statistic | P value | Odds ratio | T statistic | P value | |
Water clear | 10.44 | 11.49 | 0 | 22.60 | 13.4 | 0 |
Water tastes good | 14.08 | 15.58 | 0 | 8.24 | 9.19 | 0 |
Water free from odours | 2.47 | 5.15 | 0 | 4.07 | 6.15 | 0 |
Borehole | 0.35 | −3.48 | 0.001 | 0.20 | −6.07 | 0 |
Rainwater or tanker water | 0.24 | −4.44 | 0 | 0.13 | −6.3 | 0 |
Other non-piped water sources (i.e. wells, rivers, dams, springs, stream, etc.) | 0.25 | −6.5 | 0 | 0.10 | −9.23 | 0 |
Water clear and free from odours | 3.85 | 5.39 | 0 | 2.22 | 3.01 | 0.003 |
Clear water from other non-piped sources | 0.23 | −5.07 | 0 | 0.44 | −3.1 | 0.002 |
Water from other non-piped sources tastes good | 0.42 | −3.42 | 0.001 | 0.43 | −2.9 | 0.004 |
Water from other non-piped sources free from odours | 0.34 | −3.92 | 0 | |||
Head of household ethnicity - coloured | 3.70 | 3.39 | 0.001 | |||
Public or neighbour’s tap | 0.52 | −2.92 | 0.004 |
Free from odour | Good taste | Clear | Supply type | % Households perceiving water safe | No. households |
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N | N | N | Other (i.e. surface waters, Wells, and springs) | 3.9 | 727 |
Y | N | N | Other (i.e. surface waters, Wells, and springs) | 9.0 | 122 |
N | N | N | Piped supplies | 14.3 | 479 |
Y | N | N | Piped supplies | 29.2 | 174 |
N | N | Y | Piped supplies | 63.5 | 138 |
Y | Y | Y | Other (i.e. surface waters, Wells, and springs) | 84.6 | 406 |
Y | Y | N | Piped supplies | 85.3 | 309 |
Y | N | Y | Piped supplies | 94.3 | 333 |
N | Y | Y | Piped supplies | 96.1 | 310 |
Y | Y | Y | rain / tanker water | 98.3 | 280 |
Y | Y | Y | Boreholes | 98.8 | 628 |
Y | Y | Y | Piped supplies | 99.6 | 19413 |
Discussion
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Many potential sources of water quality data are not restricted to the point-of-use, but also entail sampling of untreated source water or water within distribution systems.
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Professional assessments of drinking water safety often rely on both testing of multiple water quality parameters and sanitary risk inspection. However, many data sources only include a subset of these parameters and may omit risk inspections altogether. Not only is there a problem of partial coverage of drinking water safety parameters in some data sets, but finding an appropriate way of integrating these measurements into a single composite metric of water safety (for example, by choosing the lowest water safety band across all measured parameters) is also potentially difficult.
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Whilst there are monitoring systems and sample surveys available, few are designed to provide nationally or provincially representative estimates.