Residents in the Nidderdale area of ​​North Yorkshire have been advised not to drink tap water under any circumstances, even after boiling, after water samples were found to be contaminated.

According to a spokesperson for Yorkshire Water, unusual chemical and physical changes have been detected in the water in 34 homes near Harrogate, with the affected areas including Darley, Maynooth Hill, Bristoth, High Bristoth, Forest Moor, Fellscliffe and Lofthouse.

A further 43 homes are still under boil-and-drink advice, the company said, but residents of the 34 homes have been told not to drink tap water under any circumstances, nor use it for cooking, brushing teeth or watering pets, although the water has been declared safe for washing clothes, cleaning dishes, bathing and toilet use.

A local resident said he had been supplied with bottled water by the company.

He said he received a call from Yorkshire Water on Friday night, saying the water was no longer drinkable even after boiling it. By the end of the week, about 64 litres of water had been supplied so he could wash vegetables and drink it, but he has not yet been told what the real problem was.

A Yorkshire Water spokesman said that routine sampling on October 10 found low levels of coliform bacteria in the water, the same group of bacteria that includes E. coli, which can cause serious illness in the elderly, children and the vulnerable.

“We have taken steps such as flushing the network, testing private supplies and installing protective barriers,” the spokesman said. Additional tests have now revealed chemical imbalances in some areas, after which affected households have been advised not to drink the water.

The company said investigations were ongoing and it was likely the issue was related to rural areas where homes had private borehole supplies in addition to Yorkshire Water.

They added that they understood the situation was frustrating for customers and they were grateful for their patience and cooperation.