Kirkmichael Distribution System - March 2009

In 2005, Scottish Water's contractors laid 5 km of new pipe from Kirkmichael village to Straloch primary school to connect it and other local properties onto the public water supply system. This area, including the school, was on a private water supply system at that time. However, the new pipe was not connected into the public system at this time since there was insufficient capacity at the treatment works to cater for it.

In April 2008, work commenced to increase the capacity of the works to allow the connection to Straloch to take place. Work on connecting the pipeline started in September 2008 with an expected completion date of December 2008. However, the work stalled due to a lack of water. A decision was made on 6 October 2008 to use water from the nearby river to flush the main. This action was at variance to Scottish Water's (SW) procedures which are in place to prevent the distribution system from being contaminated and hence protect the quality of the water supplied to customers. Flushing with river water should never have been allowed to happen. In addition, when the pipe was originally laid in 2005, precautions were not taken to protect it from contamination until it was connected into the public water supply system. This includes not protecting the open ends of the pipeline from contamination. Again this is contrary to procedures that SW has in place, so should not have been allowed. However, as soon as SW was made aware by their contractors that river water was being used to flush the main on 10 October, they gave an instruction to stop the activity immediately.

Flushing of the pipeline using potable water from tankers subsequently took place on 24 November 2008 with samples being taken both before and after flushing. Results of this sampling discovered that contamination had taken place and that additional flushing would be required. A number of leaks were also found at the same time. It was not until 16 February 2009 that the leaks had been fixed and further water samples taken following another flush. Analysis of these samples found the pipe to still be contaminated so even more flushing was scheduled for late in March 2009 with the hope of finally connecting the pipeline into the public system by the end of March 2009.

DWQR notes the lessons learned from this incident and the actions being taken by SW to prevent a recurrence. Namely, the actions are (1) for SW to communicate with its contractors to confirm the requirements to use potable water for pressure testing, (2) arrange attendance at procedures training event for Contracts Manager and (3) circulate incident report to SW Regional Managers and procedures working group to ensure learning points are disseminated.

This incident reinforces the need for SW to ensure that all staff and contractors involved in working on the distribution system are fully versed with the relevant procedures. It also highlights the need for closer supervision of work on the distribution system to ensure that the procedures are followed.

The Executive Summary from SW's report along with this assessment will be placed on the DWQR web site. The relevant Consultant in Public Health Medicine and Environmental Health Officer will be notified of this and DWQR will be monitoring SW's actions to ensure that they are discharged.