Involving the Consumer in Drinking Water Quality Testing - eWISA

INVOLVING THE CONSUMER IN DRINKING WATER
QUALITY TESTING
Fiona Hendry
Rand Water, PO Box 1127, Johannesburg, 2000. Tel: (011) 682 0911. E-mail: Fhendry@randwater.co.za
ABSTRACT
Consumers are becoming increasingly conscious of the quality of their tap water, this is due to an
increase in water quality issues in the media. There have been numerous articles comparing tap
water to bottled water which have heightened concerns of the consumer. Because of this Rand
Water decided to introduce the Tap Analysis Programme (TAP). The programme is aimed at
informing consumers about the quality of water in their own homes.
Monthly samples are taken by both internal (Rand Water staff) and external participants. These
results have enabled Rand Water to build up a data base of tap water results for various regions
within Rand Water’s area of supply. In this way Rand Water is capable of monitoring changes that
may occur in the water quality form the purification works right up to the end point. The data allows
for effective maintenance programmes to be put in place.
INTRODUCTION
Rand Water
For the last century Rand Water has been the bulk potable water supplier in an area of
approximately 18 000km 2 which extends into five provinces (Figure1). Rand Water draws its raw
water from the Vaal Dam, once purified, this water is pumped to various reservoirs (55) located in
the area of supply. On average 3200 million litres of water is supplied to more than 12 million
people and 50% of the countries industries on a daily basis.
THE TAP ANALYSIS PROGRAMME (TAP)
Consumers are becoming increasingly conscious of the quality of their tap water. This is due to an
increase in aggressive marketing of bottled water, home treatment devices and water quality
issues in the media. There have been numerous articles comparing tap water to bottled water
which have heightened concerns of the consumer. Because of this Rand Water decided to
introduce the Tap Analysis Programme (TAP). This programme is aimed at ensuring that drinking
water quality is maintained to the point of consumption and at informing consumers about the
quality of water in their own homes, thereby creating awareness based on the correct information.
TAP began in March 1998 and involved Rand Water employees as well as a few external
participants collecting samples, on a regular basis, from their taps at home. These samples were
submitted to a laboratory (initially Rand Water’s laboratory and later to an external laboratory as a
self audit process) for both chemical and microbiological testing. The participants bring in samples
on a voluntary basis and all interpreted results of the analysis are given to them.
The existing TAP programme supplies valuable information pertaining to water quality of Rand
Water and the end consumer. Rand Water has the data to prove that the water supplied to the
municipalities is of an excellent standard. The data collected through the TAP programme indicates
whether or not the standard is maintained through out the system, while simultaneously monitoring
the effectiveness of the municipalities’ infrastructure.
Proceedings of the 2004 Water Institute of Southern Africa (WISA) Biennial Conference 2 –6 May 2004
ISBN: 1-920-01728-3 Cape Town, South Africa
Produced by: Document Transformation Technologies Organised by Event Dynamics

Figure 1. Rand Waters area of supply.
Figure 2. Water supply route.
Rand Water supplies potable water to 16 municipal areas. The programme currently concentrates
on the more densely populated regions where the bulk of potable water is consumed. There are
plans to include the other municipal area into the programme, however, the routine sampling is
dependent on the interest of the participant.
Table 1. Municipal areas/ Current number of TAP participants.
Municipal Area Current Number of Municipal Area Current Number of
TAP Participants
TAP Participants
Delmas NONE Midvaal 3
Ekurhuleni 9 Mogale NONE
Emfuleni 3 Ngwathe NONE
Highveld East NONE Randfontien NONE
Johannesburg 12 Rustenburg NONE
Kungwini NONE Tshwane 3
Lesedi NONE Westonaria NONE
Metsimaholo NONE

RESULTS
All samples taken for the TAP programme are analysed by an accredited laboratory. Twenty five
variables are monitored on a monthly basis, these variables include:
• Chemical and Physical properties
Alkalinity, Colour, Conductivity, Turbidity, Hardness, pH, pHs and Calcium Carbonate
Precipitation Potential(CCPP).
• Micro Elements
Cadmium and Lead
• Macro Elements and Miscellaneous Determinants
Aluminium, Manganese, Calcium, Copper, Fluoride, Magnesium, Iron, Nitrate, Sulphate and
Zinc.
• Microbiological
Total Chlorine, Standard Plate Count, Total Coliforms, Faecal Coliforms and Confirmed E.coli.
Of the twenty five variables monitored Alkalinity, Hardness, pHs, CCPP and Total Chlorine do NOT
have specified standards set out in the SABS 241:2001 recommended drinking water standards.
These variables are measured against internal standards, however, due to the fact that there are
no external standards they will not be discussed further.
All but three of the remaining twenty variables comply with SABS standards, the three that have
not complied with the standards during 2003 are discussed in more detail below.
Turbidity
According to the SABS standards the recommended value for turbidity should be less than 1 NTU
for 95% of the time to comply with class 1. The results below show that the water in Rand Waters
distribution network (Distribution) complies with this standard completely. The water tested at the
end consumer (TAP) does not always comply with the recommended standard.
Figure 3. Compliance level of turbidity.
Iron
The SABS standards recommend that the iron value be less than 0.2 mg/ℓ for 95% of the time to
comply with class 1. It is clearly illustrated in the graph below that the water in the distribution
network fully complies with the recommended standard. Although the iron values for the samples
taken at the end consumer comply with the standard for the most part it is clearly seen that the iron
content in the water can change quite considerably from the purification station to the end
consumer.

Figure 4. Compliance level of iron.
Standard Plate Counts
The SABS standards state that the number of Heterotrophic Bacteria per 1mℓ (cfu per 1ℓ) should
not exceed 1000 for 96% of the time to comply with the class 1 standard. The water monitored in
the distribution network complies with this completely, however, the water monitored at the end
consumer shows a decrease in bacteriological quality.
CONCLUSION
Figure 5. Compliance level of the standard plate count.
The results of the monthly samples taken indicate that the water that reaches the end consumer is
still of potable quality. The three variables that do show deterioration do not have a negative health
impact. The increase in turbidity could indicate the need to clean the municipal reservoirs in certain
areas. In the past Rand Water used the turbidity values to determine the need for cleaning the
reservoirs, the information that is collected through this programme could be used by the
municipalities to develop their reservoir maintenance programmes. The increase in iron values
gives an indication of deterioration of pipe lines, this may also be useful information to consider
when pipeline renovation programmes are implemented. Although there is a remarkable increase
in the SPC results at the end consumer, there is still no indication that the water quality is worse as
no total or faecal coliforms are detected. The SPC values could be lowered by decentralised
dosing with chlorine within the municipal distribution networks. This would further ensure that
chlorine related taste and odour complaints are limited.