Fed-up residents claim a change in their water supply has left them with itchy skin, mouth ulcers, upset stomachs and being unable to drink from the tap.
Since United Utilities blended soft water from Ennerdale with harder water from Egremont boreholes a few weeks ago, people say they've noticed a huge difference.
Many say they're forced to buy bottled water to drink as the tap water tastes "disgusting" and is giving them upset stomachs, with one mother even using it to make her baby's feeds.
However, the water company said the change would not cause these problems, insisting that the water is safe.
Catherine Dodgson's four-month-old daughter Olivia had sickness and diarrhoea when she made her milk formula using the water, so has now switched to bottled.
"She hasn't had sickness and diarrhoea since I started using bottled water," said the Cleator Moor mum. "I have went back and tried the tap water a few times and the same thing happens. I'm buying bottled water which is wrong when I'm paying rates."
There are claims the water is also leaving stains on cups, which can only be removed with bleach, and is making people still feel "dirty" after showering and bathing.
Chris de Cordova, who lives at Thornton Road, in Whitehaven, said at first, she thought recent problems she's had with dry smeary eyes and an exceptionally dry mouth was due to her getting older.
"I now think it could well be my body reacting to going from very pure water to what we have now," she said.
"I have also noticed the lack of lather with shampoo, shower gel, washing up liquid, handwash etc. Also random itching!
We have started to use bottled water in the kettle and for drinking but can't avoid it for showers and other washing purposes. In the few days since we started this I have noticed an improvement."
People were first made aware of the change a few weeks ago when their kettles began popping.
The water supplies properties in Workington, Whitehaven, Distington, Cleator Moor, Moresby, Egremont, Frizington, Seascale, Gosforth, Bootle, St Bees, Ennerdale Bridge and the smaller villages in between.
Steve Carr, who lives at Loop Road, said his kettle began popping around a month ago, but since then, he has discovered a raised, spotty rash on his skin.
"It seemed to get worse the day after a bath," he said. "I also had dry skin around my mouth until I stopped drinking water from the tap."
He added that after hearing about other people having similar issues, it's hard to believe it's a coincidence.
United Utilities water and scientific services director Martin Padley said: “I can reassure residents in West Cumbria that the detailed analysis we carry out regularly on the water supply shows there is nothing amiss.
“Although the supply contains more minerals now that we are blending water from Ennerdale Lake with borehole water from Egremont, it still meets all the very strict UK water quality standards.
“If anyone has concerns or they would like to ask any questions I hope they will come along and discuss it at one of our drop-in sessions.”
The sessions are being held on Thursday, July 13, The Beacon, West Strand, Whitehaven, 1pm - 8pm. Another session in Egremont is still to be confirmed.
Abstracting water from Ennerdale will cease once the new £300m pipeline linking West Cumbria to Thirlmere Reservoir is complete, United Utilities said. The work is expected to be completed by 2022.
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