The 'viral load' has seen a rise of between 10% and 50%.
Higher levels of the Covid-19 virus have been found in wastewater in recent weeks.
The latest report from the HPSC, shows higher levels of the virus in the majority of samples taken at the start of the month.
The 'viral load' increased by between 10% and 50% in 23 of 29 locations around the country.
The presence of the Covid-19 in wastewater is linked with the circulation of the virus among the population.
The HPSC's latest report shows there were 46 cases of the virus reported in the midlands last week - 24 of those were in Westmeath, followed by 15 in Offaly, and seven in Laois.
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