The "do not consume" notice for water on Achill Island and some parts of the Co Mayo mainland was introduced due to a swell in numbers from people on 'staycations', Irish Water has said.
The bar on using water entered its fifth day on Tuesday.
Irish Water’s head of asset Management Séan Laffey said levels of demand are 50 per cent higher than this time last year, which has led to higher aluminium levels.
“This is not a boil water notice. This does not make it safe to drink,” he told RTÉ Radio. “ This water should not be made for drinks or washing food or brushing teeth.”
However, water on the island can be used for bathing, flushing toilets and washing utensils.
Mr Laffey said that an unexpected consequence of the Covid-19 crisis was that more people were holidaying in Ireland and visiting places like Achill. The water treatment plant at Achill has a capacity for 3,000 people and for 98 per cent of the year this works adequately, he added.
Irish Water, in consultation with the Health Service Executive, issued the advice not to consume the water, whether from public supply or group water schemes, on any part of the island or parts of the mainland due to increased levels of aluminium and turbidity – the solid particles that cause cloudy water.
Almost 2,500 residents of the island have been warned that while nobody should consume the water or wash food with the water, it was especially important it was not consumed by babies or infants.
“Everyone on the island, whether supplied by the Achill Public Water Supply Scheme or any of the group water schemes and parts of the adjacent mainland, are affected by this notice,” Irish Water said in a notice on Monday which extended the initial “do not consume” notice issued last Friday.
“Irish Water would like to remind customers that the notice remains in place and that water should not be consumed or used to wash foods.”
Tankers were supplying water at 29 locations on the island, including from schools and churches. Residents and tourists have been told to present at those locations with their own containers to receive their supplies of drinking water.
Irish Water said the water supplied by tanker should be boiled before consumption as a precautionary measure. It added it was working with Mayo County Council to resolve the problems and also to supply bottled water to its "vulnerable customers".
