People in the Athlone area of Westmeath face water restrictions tonight due to low levels in Annagh Reservoir following a pollution incident.
Water intake at the treatment plant was affected by the incident at the weekend.
Irish Water and Westmeath County Council have said that in order to allow water supplies to build back up, a water restriction will be in place from 10pm tonight until 6am on Wednesday morning.
The restrictions will impact customers in Baylin, Mount Temple, The Ories, Garrycastle, Dublin Road, Ardnaglug, Fardrum, Moydrum, Blyry, Killyon Hill, Bonavalley, Athlone and surrounds in Co Westmeath.
Meanwhile, people in the Mullingar area are being asked to conserve water due to low levels in Lough Owel.
The lake supplies water to 50,00 homes and business on the Mullingar Water Supply Scheme.
Irish Water says levels in the lake have reached critically low levels.
In a statement, they said there has been just a quarter of average expected rainfall up to 24 January.
As a result the normal expected rise in water levels has not materialised.
Irish Water say they are "working to proactively manage the water level in the lake in order to reduce the risk of water outages in the coming summer and autumn."