Dr. Michelle Minihan:

It is disappointing to be adding five supplies to the remedial action list for persistent THM exceedances. By persistent, we mean three or more months where we have seen this occur. The Clareville treatment plant, because of its size, has caused those numbers to jump to 114,000 people. We have had persistent THM exceedances there for six months of this year. It is a persistent and ongoing problem, unfortunately, because of the way THMs form when organic matter reacts with the chlorine in the water that is used to disinfect it. We cannot compromise disinfection, so we must add the chlorine. What is key, however, is that the treatment processes at the plant are optimised and the network managed appropriately to ensure there is no additional THM formation as the water moves through the network. For example, if it takes four days for water to move from the plant to the extremity of the networks, then for all that time there is potential for THMs to form. It is key therefore to optimise the plant and to install whatever treatment processes are needed to remove THMs. Equally important, though, is ensuring the distribution network is managed appropriately and that it is compliant as well. I say this because it is compliance at consumers' taps that is the point of compliance.