Irish Water has lifted a "do not use" notice for 1,200 customers west of Dunboyne in Co Meath.
The "do not drink, do not use for food preparation or do not wash" advice had been in place for Kilcloon, Moygaddy, Killeany, Kilgraigue, Harristown, Brownstown, Ballynare, Butlerstown, Staffordstown, Brownrath, Blackhall Little, Waynestown, Harlockstown and Ballymacoll.
The notice was issued yesterday after customers noticed high levels of chlorine in the water supply.
Irish Water said it worked with Meath County Council to carry out a programme of flushing of the network to return the chlorine levels to the correct drinking water standards and liaised with the Health Service Executive on sampling results.
Irish Water said the notice was lifted this evening when the HSE was confident the water was safe to use again.