Dr. Michelle Minihan:

As of last Friday, the total population with persistent THMs in their water supply is 243,137 across 24 water supplies. Given that between 4 million and 4.2 million people are on public water supplies, it is probable that less than 10% of people are affected. Nonetheless, it is a significant issue. Unfortunately, we have seen a increase in the number of water supplies where we are detecting THMs. Some 58 public water supplies failed to meet the standard in 2021, which was an increase on 35 public water supplies in 2020. The good progress we had seen was reversed in 2021. For THMs, the problem is persistence. Irish Water needs to install treatment to remove the THMs and prevent them from forming, or optimise the plant to ensure they cannot form as water moves through the network to get to consumer's taps because that is where the point of compliance is. Water does not just need to be compliant leaving the plant; it also needs to be compliant at consumer's taps in their homes.