Riddell Road Tank Incident, 20 Feb 2014 (Sunbury locality)

Issue

Routine sampling at the Riddell Road tank resulted in an E.coli detection of 2 orgs/100ml.

Actions

An incident was declared at a minor level 1 level due to the possible impact. The tank was spot dosed and an integrity inspection carried out with no obvious issues found.

A network trace was conducted to identify the impacted supply area and Western Water’s communications team were engaged to organise the logistics around a potential boil water alert should the follow up sampling return positive results.

Resampling was conducted at the tank and two reticulation sites downstream in an effort to increase the data set, with three sets of samples collected at each site for three
consecutive day. All resampling was clear.

A key learning from this incident is comprehending the logistics involved in delivering a boil water notice when the impacted number of properties is large (in this instance 1,825).