Four thousand premises in Kerry, including households and tourism sites, have been left without water today after a major mains linked to the county's largest water treatment plant near Killarney burst overnight.
High temperatures have been a factor in previous pipe bursts in the area.
Irish Water said crews from Kerry County Council are working to repair the burst on the mains pipe from Lough Guitane treatment plant to Sheheree Reservoir in Muckross, Killarney.
The lake supplies customers in Killarney and Tralee, Castleisland, Castlemaine and areas of east Kerry.
Irish Water says it hopes supply will return in the afternoon, but warns there may be further interruptions.
Regional Asset Operations Lead at Irish Water Oliver Harney said "as the network refills it can be put under additional strain, so repair crews are on standby in case of further issues or bursts. As supply returns, we would also like to remind customers to continue to conserve water".
A customer care helpline is open 24/7 on 1800 278 278 and customers can also contact Irish Water on Twitter @IWCare with any queries.
Last week, overnight water conservation measures were put in place in order to guarantee supply to Killorglin town and environs where thousands gathered for the annual three-day Puck Fair Festival.
High temperatures combined with high demand meant water reservoirs supplying areas west of Killarney as well as Milltown and the Killorglin region were running low.
