The amount of Covid-19 detected in the country's wastewater has been increasing at least 10-fold each week for the last couple of weeks.
Scientists have been sampling wastewater since 2020; with positive detections of Covid providing an early warning that someone in the community was infected.
The virus is now being picked up in nearly every community.
Dr Brent Gilpin, from the Institute of Environmental Science and Research, spoke to Corin Dann.
