Our Ref: DWI/2/10 Event 30/10 Date: 9 June ... - Derry City Council

5.3.4 The PHA advised NI Water on 31 December 2010 that there should be increased
monitoring at Clay Lake WTWs and enhanced monitoring in the distribution systems
and this was also to apply to other WTWs receiving tankered water. After this date,
Carran Hill WTWs was sampled daily and Clay Lake WTWs was sampled daily except
for 4 January 2011. However, Camlough WTWs was not sampled on the 1, 2 or 3
January 2011 and there were no additional distribution samples taken. The
Inspectorate requested an explanation as to why these additional samples were not
taken.
5.4 Regulation 15 Sampling: new sources
NI Water has a responsibility to ensure it has taken adequate precautions before
bringing sources into supply which are not currently in use. Regulation 15 requires NI
Water to put in place appropriate monitoring of any new source, either before bringing
in the source, or as soon as practicable afterwards. NI Water may, however, bring in
new sources as a matter of urgency in order to prevent an unexpected interruption in
supply, but this may only be done in circumstances where a regulation 27 risk
assessment has been carried out.
In bringing in the Cabragh and Glarryford boreholes, as these supplies had not been in
use for the preceding 6 months, NI Water was required to have undertaken monitoring
and a risk assessment. Appropriate monitoring was undertaken for these boreholes to
enable these supplies to be brought into service.
5.5 Regulation 16 Collection and analysis of samples
This regulation details specific requirements for the collection and analysis of samples.
The Inspectorate requires an assurance from NI Water that all personnel, including
contractors, who were taking samples during the incident, had been accredited to
undertake sampling or had undergone appropriate training, and that samples were
taken, handled and transported appropriately in compliance with this regulation.
5.6 Regulation 17 and 18 Investigations
Where NI Water has reason to believe that the water supplied fails, or is likely to fail,
to meet the standards of wholesomeness specified in the regulations, it is required to
investigate the cause of that failure or likely failure. Normal reporting and assessment
procedures apply to investigations of all contraventions. 34 contraventions were
notified to the Inspectorate under these regulations.
5.7 Regulation 26 Disinfection and other treatment arrangements
5.7.1 Regulation 26 requires NI Water to ensure that any disinfection process carried out at
any site is effective and that there is documented evidence to demonstrate verification
of the performance of the disinfection process. The regulation also requires that all
water supplied for Regulation 4(1) purposes (Wholesomeness) is disinfected.
5.7.2 No documentation was provided by NI Water to demonstrate verification of
disinfection. NI Water is required to meet the requirements regarding verification of
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