Ms AnnMarie Farrelly:

The period of poor water quality was shorter than the gap that has been discussed at the committee in terms of the 3 p.m. commencement of the debris accumulation. The water quality had deteriorated by 6.15 p.m. and reached critical level at 7.50 p.m. It was identified at 9 o’clock.

That said, there was a failure in our monitoring system on that day. That is subject to investigation and includes a disciplinary process which is under way.

In reaction to that, I can strengthen the systems that are there. That strengthening has already happened which is evidenced in terms of the prompt reaction taken on Sunday to this current incident. This includes a level of automation. Alerts are sent automatically to the on-call duty manager, for example. It also includes increased requirements from the on-call duty manager. I want to introduce increased out-of-hours site visits.

The SCADA, supervisory control and data acquisition system, which helped us identify the problem from 21 October, can be monitored remotely or on-site. Increased monitoring and reviewing of that system is important to understand if it is working well or if there is a problem we can address. It is not just a reliance on alarms. It is that plus regular auditing and review of what the reports tell us. Bringing in these improvements is under way and will help prevent this type of incident happening again.

The overriding shutdown of the system, which is now in place, would have prevented the incident in any event. Many improvements have been introduced in the past two weeks. Some are ongoing over the next couple of days. However, they will help to prevent this type of incident.

The ongoing incident is different as the committee has recognised. That relates to the quality of the raw water. We would be hopeful that the treatment will return to normal later this evening, provided there is no further deterioration in the raw water supply. That then instigates a process, outlined by the Environmental Protection Agency, EPA, earlier, which leaves it in a position to commence its audit. There are several steps to go through once the water returns to normal.

We are not in a position to give a precise timeline for the next day or so.