The aeration system that had the potential to significantly reduce the level of trihalomethanes (THMs) in Tottenham’s drinking water is struggling to make much of a difference. The Town of New Tecumseth hired engineering consultant R.V. Anderson Associates Limited to conduct a year-long review of the effectiveness of the $800,000 aeration system activated at the Mill Street reservoir in October 2019. The report concluded that the annual running average level of THMs declined 10 per cent compared to prior sample data from 2019. The report also found the variability of THM levels has been reduced by six to 10 per cent within the distribution system.