The water supply in parts of Co Louth is being examined after high levels of lead were detected in a number of samples.
The County Council says it is working closely with the Environmental Protection Agency and the HSE to address the matter.
The council was informed by the EPA on Tuesday that safe limits for lead had been breached in several samples from commercial and residential premises.
Ten separate locations in older parts of Dundalk and Drogheda, as well as in rural areas, are believed to have been identified as having unsafe levels of lead.
The news follows widely publicised problems with lead in the water supply in parts of Galway city.