Thousands of people in Cavan have been told not to drink their tap water.
It comes after high levels of manganese was found in the Bailieborough public water supply.
Up to 7,785 homes and businesses are affected in Bailieborough, Killinkere, Virginia, Crossbane, and Mullagh.
People are also being warned that boiling the water will not make it safe, and not to use it to feed babies.
Irish Water said they will put water tankers in place from 1pm today for customers.
- Water tankers will be located in the following areas: