SUPERMARKET shelves were cleared of bottled water as United Utilities urged residents to continue to boil water from their taps.

Engineers are continuing to flush out the pipe network surrounding Franklaw water treatment works in Preston, where routine tests found parasites in the water.

Samples were yesterday improving, but the water board’s advice to boil water as a precautionary measure for all drinking, food preparation and brushing of teeth will remain in place all weekend.

Water should also be boiled and cooled before being given to pets, while dishwashers should be set to 65 degrees or above.

Confusion arose in East Lancashire after United Utilities said those living in Blackpool, Chorley, Fylde, Preston, South Ribble and Fylde all needed to boil their water before using it.

However, it later emerged five areas across Blackburn and Darwen were also covered by the warning.

They are Roman Road Industrial Estate, Stockclough Lane, Finnington Lane, and Finnington Trading Estate in Feniscowles, Knott Street, Skelton Street, Parkdale Gardens, and St Albans Road, all in Darwen, and Oakenhurst Farm in Lower Darwen.

Water board employees were yesterday due to post cards through letterboxes at homes affected, in addition to communicating advice through social media, newspapers, radio, and TV. Martin Padley, at United Utilities, said: “The advice is being given purely as a precautionary measure as we carry out additional tests today.”

Despite United Utilities’ advice water taken from taps can be made safe by boiling, supermarkets in the affected areas faced a surge in demand for bottled water. And public health lawyers called for an investigation into how and why the parasite – microscopic bug Cryptosporidium – ended up in the water.

Amandeep Dhillop, from Irwin Mitchell, said: “Cryptosporidium can have serious health implications for those affected and in our work we have seen first-hand the long-term issues that it can cause. Protecting the general public from outbreaks of this nature is the main priority and it is vital that a thorough investigation is carried out, and that steps are taken to attempt to reduce the likelihood of further contamination occurring in the future.”