Ed Walker of Blog Preston writes the reason why Prestonians couldn’t drink their water without boiling it for a month has finally been revealed.

United Utilities has been fined after a cryptosporidium outbreak at its Franklaw treatment plants to the north of Preston,

The Drinking Water Inspectorate found the problems came from the Franklaw works using a different reservoir to source water

Rainwater running off agricultural land was able to access an underground water tank at Barnacre.

A ‘planned change in operations’ allowed the entry of the contaminated water into the treatment process.

Traces of cryptosporidium were detected in the water at Franklaw triggering a shut off of supplies for 700,000 people across Lancashire.

Supplies for many were knocked out for a month during the summer of 2015 as engineers worked to fix the issue.

At Preston Crown Court the hearing fined United Utilities £300,000 and additional costs of £150,000 were also agreed. The firm had pleaded guilty to supplying water unfit for human consumption.

United Utilities was criticised for not acting fast enough to issue the boil water warning to households and businesses.

It has since paid out £20million in compensation to customers through reduced water bills.

The fine was branded ‘pathetic’ by Preston MP Mark Hendrick.