Irish Water has said that around 1,200 customers in Co Meath have been told not to use their tap water for drinking, washing or preparing food because of dangerous levels of chlorine in the supply.
The homes and businesses affected are in the Kilcloon, Moygaddy, Killeany, Kilgraigue, Harristown, Brownstown, Ballynare, Butlerstown, Staffordstown, Brownrath, Blackhall Little, Waynestown, Harlockstown, Ballymacoll areas.
A spokeswoman for the company said it had received no direct reports of children suffering rashes because of the problem but had seen some reports on social media.
She said that anyone experiencing any ill effects should contact their GP.
Irish Water said it is flushing the excess chlorine out of the system and hopes to restore a safe supply later tonight, but added it could not say for sure when the no drink/no wash notice will be lifted.
It said it is monitoring the chlorine levels in the water and working with the HSE.
The company said that for now, the tap water in the affected areas should not be used for any purpose except for flushing toilets and flushing internal house plumbing systems.
Irish Water said bottled water will continue to be available for collection from the Kilcloon Church and Kilcloon School today.
Manned water tankers will be in place from 5.30pm at the Kilcloon Church and Kilcloon School and will remain in place until tomorrow afternoon.
Customers are reminded to use their own containers when taking water from the tankers and to boil water before consumption as a precautionary measure.
Anyone looking for more information can contact the Irish Water's 24-hour customer care line on 1850 278 278.